tag:theconversation.com,2011:/us/topics/wind-3872/articlesWind – The Conversation2017-08-03T21:10:42Ztag:theconversation.com,2011:article/766672017-08-03T21:10:42Z2017-08-03T21:10:42ZIf we keep subsidizing wind, will the cost of wind energy go down?<figure><img src="https://images.theconversation.com/files/180044/original/file-20170727-22996-166jcmh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">As more wind turbines have been put in place, the cost of wind energy has gone down. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/130749842@N07/16328618272/">Dad of T&S</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span></figcaption></figure><p>There are high hopes for renewable energy to help society by providing a more stable climate, better energy security and less pollution. Government actions reflect these hopes through policies to promote renewable energy. In the U.S. since 1992 there’s been a <a href="https://energy.gov/savings/renewable-electricity-production-tax-credit-ptc">federal subsidy</a> to promote wind energy, and many states require electricity utilities to use <a href="http://www.nrel.gov/tech_deployment/state_local_governments/basics_portfolio_standards.html">some renewable energy</a>. </p>
<p>But when is the right time to stop government support for an energy technology? </p>
<p>This is a timely question: Rick Perry’s Department of Energy is currently working on a <a href="https://theconversation.com/are-solar-and-wind-really-killing-coal-nuclear-and-grid-reliability-76741">grid reliability report</a> that many expect to argue that wind and solar cause reliability problems because they don’t supply power continually. A conclusion like this can be used to justify removal of government subsidies or regulations favoring other sources of energy. </p>
<p>Subsidies need not last forever – there can come a time when its objective has been achieved or experience suggests the subsidy is not working as intended. </p>
<p>Is it time to end subsidies for wind? A big part of the answer to this question lies in whether subsidies are actually making wind cheaper. </p>
<h2>Why subsidize energy technology</h2>
<p>The justification for subsidizing a given technology is that it delivers public benefits that outweigh the subsidy cost. If a technology shows promise to become cheap enough, the subsidy can be viewed as a temporary stimulus to bring it a point where it can stand on its own. </p>
<p>For example, in the early days of the semiconductor industry, integrated circuits were too expensive for consumer markets. Government demand for military applications provided a critical bridge to bring down costs and activate broader markets. </p>
<p>On the other hand, subsidizing an emerging technology that has trouble bringing down costs may be inefficient. For decades, the U.S. government has subsidized or mandated production of corn ethanol. <a href="https://www.greentechmedia.com/articles/read/the-true-cost-of-corn-ethanol">Yet ethanol is still not market-competitive</a>, at least not with recent crude oil prices. </p>
<h2>Wind power’s ‘learning curve’</h2>
<p>The price for wind power has gone down over the years, but how cheap is it getting? There is a surprisingly diverse set of answers to this question. There are over 100 existing studies of wind cost trends, with results ranging from wind power becoming more expensive over time to becoming cheaper so quickly that it will soon be cheaper than fossil fuels. Curiously enough, while researchers have <a href="http://www.sciencedirect.com/science/article/pii/S0301421515002293">recently started to note disparities between studies</a>, no one has yet grappled with explaining and reducing such variability. This is, unfortunately, a common situation in many research domains: Various groups get conflicting results from similar analyses, but no one works on understanding why these differences arise. </p>
<p><a href="http://www.sciencedirect.com/science/article/pii/S0301421517301763">In a recent paper</a>, we sought to better understand cost reductions in wind power by finding patterns in historical trends. </p>
<p>Wind costs follow what economists call a learning curve: For every doubling of wind production, the cost goes down by a fixed percentage. For example, if the price of electricity from wind is 10 cents per kilowatt-hour with a given number of wind farms, a 10 percent “learning rate” means that wind electricity would cost 10 percent less, or 9 cents per kilowatt-hour, if one doubles the number of wind farms. </p>
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<p>Our main finding was that the learning rate for wind power is in the range of 7.7 percent to 11 percent. That means if more wind power is installed and the cost of energy continues to decline as it has in recent years, the cost of generating electricity with wind will fall from 5.5 cents/kilowatt-hour today to 4.1–4.5 cents/kilowatt-hour in 2030.</p>
<p>Previous studies obtained learning rates from -3 percent to +33 percent, the minus sign indicating wind becoming more, rather than less, expensive over time. Why are the results so different? We showed that one can get very different outcomes depending on the method and data range used. </p>
<p>First, we believe it is important to account for wind power costs in terms of the total cost to generate electricity. Many prior studies measured wind cost as the price to build the capacity to make electricity at peak wind times. But this is a poor measure because much of the progress in wind technology in recent years has been to generate more power when the wind is weaker. </p>
<p>Secondly, it is important to treat wind power as a global industry. The adoption of wind in one country helps the industry develop and grow so that wind becomes cheaper in other countries. Modeling wind adoption in only one nation can skew results. </p>
<p>Finally, results depend strongly on the date range of data used. Even with an identical method, the estimated learning rate can change up to 10 percent depending on which years of data you use.</p>
<h2>To subsidize or not to subsidize?</h2>
<p>So if wind costs will fall to 4.1–4.5 cents/kilowatt-hour in 2030, as we found, what does this mean for wind subsidies? The <a href="https://www.eia.gov/outlooks/aeo/">U.S. Energy Information Agency</a> projects the cost of natural gas and coal power in 2030 will be 4.5 and 5 cents per kilowatt-hour respectively. Taking these numbers at face value, wind is on track to become cheaper than fossil fuels as a source of electricity. </p>
<p>One must be cautious, however, in feeling too sure of forecasts. Technologies and fuel prices can go in unpredictable directions. Also, wind is an intermittent resource, meaning it can’t provide round-the-clock power as fossil fuels can. There is an additional cost to this intermittency, which is very difficult to predict.</p>
<p>Also, being cheap doesn’t mean we will soon be able to switch to 100 percent wind. To meet electricity demand continually, we will need a combination of energy storage, lowering power consumption at certain times (known as demand response) and traditional “firm” power production. </p>
<p>This said, the past suggests a trajectory in which wind becomes economically competitive with fossil fuels. Our study shows that support policies, such as the current Production Tax Credit, are contributing to lowering wind costs. As such, continued subsidies are expected to enable a smoother and cheaper transition to a sustainable energy system.</p><img src="https://counter.theconversation.com/content/76667/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eric Williams receives funding from the U.S. National Science Foundation.</span></em></p><p class="fine-print"><em><span>Eric Hittinger receives funding from the US National Science Foundation. </span></em></p>If history is a guide, policies that promote wind power expansion will lead to lower prices – potentially beating fossil fuels in the US by 2030.Eric Williams, Associate Professor of Sustainability, Rochester Institute of TechnologyEric Hittinger, Assistant Professor of Public Policy, Rochester Institute of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/798342017-06-23T01:15:02Z2017-06-23T01:15:02ZEnergy wonks have a meltdown over the US going 100 percent renewable. Why?<figure><img src="https://images.theconversation.com/files/175277/original/file-20170622-26496-1xygj4m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">You may agree the U.S. should move to renewables, but how quickly can we do it and how? </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/dukeenergy/5187449971/in/photolist-8Up39B-r7MGKr-Sd73np-r3ek5k-TrWpez-4vmCJ8-qaM6G9-r7GKg5-r7GGYu-qKDkg9-r39wqy-q6risB-9XCZ1t-SRXbNQ-8Us2aC-8XgMPk-dQwbHp-r7MFEF-qQmQKT-Td66Ww-4c1MqY-r35dQF-r5upKw-qQcCF1-8F1rdR-dQwbWD-7R6P1h-cxN7i-cCg8bm-8Up26i-8Us2Pm-dQBN2S-6bswdb-fg37Qz-dQBMNw-q6dCNY-dQurxt-TR4aUA-dQBMUE-dpJCTD-TrWnLV-b7ZQQP-a89Zsh-dQBMWA-a8779z-8q4Uqn-nizNcC-4b9QEu-eLfYKs-qKDgZj">Duke Energy/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Science is messy, but it doesn’t have to be dirty. </p>
<p>On June 19, a group of respected energy researchers released a <a href="http://www.pnas.org/content/early/2017/06/16/1610381114.full">paper in the journal Proceedings of the National Academy of Sciences</a> (PNAS) that critiqued a widely cited <a href="http://www.pnas.org/content/112/49/15060.abstract">study</a> on how to power the U.S. using only renewable energy sources. This new paper, authored by former <a href="https://theconversation.com/profiles/christopher-clack-222048">NOAA researcher Christopher Clack</a> and a small army of academics, said that the initial 2015 study had “errors, inappropriate methods and implausible assumptions,” about using only the sun, wind and water to fuel the U.S. </p>
<p>What followed was a storm of debate as energy wonks of all stripes weighed in on the merits of the PNAS analysis. Mark Z. Jacobson, a Stanford University professor who was the lead author of the 2015 study, shot back with <a href="http://www.pnas.org/content/early/2017/06/16/1708069114.full">detailed</a> <a href="https://www.ecowatch.com/pnas-jacobson-renewable-energy-2444465393.html">rebuttals</a>, in one calling his fellow researchers “fossil fuel and nuclear supporters.” </p>
<p>Why the big kerfuffle? As an energy researcher who studies the technologies and policies for <a href="https://theconversation.com/the-old-dirty-creaky-us-electric-grid-would-cost-5-trillion-to-replace-where-should-infrastructure-spending-go-68290?sr=2">modernizing our energy system</a>, I will try to explain. </p>
<p>In general, getting to a clean energy system – even if it’s 80 percent renewable – is a well agreed-upon goal and one that can be achieved; it’s that last 20 percent – and how to get there – that forms the main point of contention here.</p>
<h2>‘Energy Twitter’ on fire</h2>
<p>Jacobson’s seminal <a href="http://www.pnas.org/content/112/49/15060.full">paper</a>, which was also published in PNAS, tied together a significant amount of work of his own and others showing that all energy used for all purposes in the U.S. could come from with wind, water and solar (WWS) by 2050. </p>
<p>What about when the sun doesn’t shine, the wind doesn’t blow or water is unavailable? His findings postulated that significant amounts of energy storage would be needed, mostly in the form of heat and hydrogen, to meet energy demand when there isn’t enough renewable energy and to store it when there’s too much. They also concluded this scenario would be cheaper than a world that relies on other technologies such as nuclear, <a href="http://www.ccsassociation.org/what-is-ccs/">carbon capture</a> and other methods of reducing carbon emissions. </p>
<p>The Clack rebuttal was blunt and cut deep at the assumptions that underlie the work of Jacobson and colleagues. The same PNAS issue also included a <a href="http://www.pnas.org/content/early/2017/06/16/1708069114.full">counter-rebuttal</a> to Clack from Jacobson. </p>
<p>Energy Twitter – that is, energy wonks like me on Twitter – <a href="https://twitter.com/search?q=clack%20et%20al&src=typd">exploded</a>. </p>
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<p>So why all the fuss?</p>
<p>Much of the heat from this debate seems to stem from Jacobson making some pretty bold claims in and about his paper, going so far as to tell MIT Technology Review that “<a href="https://www.technologyreview.com/s/608126/in-sharp-rebuttal-scientists-squash-hopes-for-100-percent-renewables/">there is not a single error in our paper</a>.” That is a very, very bold claim and, depending on how it is interpreted, could be read to say that the study authors’ model is perfect, which of course it is not, as none are. </p>
<p>This debate may seem arcane, but it has significant political and societal implications. </p>
<p>Some <a href="https://twitter.com/MarkRuffalo/status/246371451790319616">celebrities</a> have signed on to Jacobson’s vision and have pressed for policies formed around his analyses of the feasibility of an entire energy system that runs 100 percent off of wind, water and solar. If policymakers buy into the technical and economic assumptions in the paper, it has big implications for the direction of state, local and national policies.</p>
<p>Detractors, meanwhile, have raised a number of concerns. In particular, they argue that decisions made based on Jacobson’s analyses alone could lead to <a href="https://www.nytimes.com/2017/06/20/business/energy-environment/renewable-energy-national-academy-matt-jacobson.html">serious overinvestment in only the technologies considered</a>, which could possibly backfire if the costs turn out to be higher than expected.</p>
<h2>The nitty-gritty</h2>
<p>To make projections around how the future energy system will work, researchers create computer-based models, input assumptions and then run simulations. </p>
<p>The rebuttal from Clack and co-authors focused on <a href="http://www.vibrantcleanenergy.com/wp-content/uploads/2017/06/Backgrounder_Clacketal_June2017.pdf">four major issues</a> they saw with the WWS paper: 1) modeling errors, 2) implausible assumptions, 3) insufficient power system modeling and 4) inadequate scrutiny of the input climate model, which informs how much solar and wind power are available for power generation. Here are some highlights with my own thoughts sprinkled in.</p>
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<a href="https://images.theconversation.com/files/175279/original/file-20170622-11971-1dxl12i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/175279/original/file-20170622-11971-1dxl12i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/175279/original/file-20170622-11971-1dxl12i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=228&fit=crop&dpr=1 600w, https://images.theconversation.com/files/175279/original/file-20170622-11971-1dxl12i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=228&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/175279/original/file-20170622-11971-1dxl12i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=228&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/175279/original/file-20170622-11971-1dxl12i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=287&fit=crop&dpr=1 754w, https://images.theconversation.com/files/175279/original/file-20170622-11971-1dxl12i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=287&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/175279/original/file-20170622-11971-1dxl12i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=287&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Up for debate: hydropower can provide steady power when solar and wind sources are not available, but can they be expanded without much economic and environmental cost?</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/briarcraft/26271598323/">BriarCraft/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>Clack takes issue with the amount of hydroelectric power that Jacobson assumes is available. In their rebuttals, they spar over the exact numbers, but Jacobson assumes there is about the same amount of total energy produced from hydropower in 2050 as today, although when, and at what rate, that energy is produced is a crucial question. </p>
<p>In Jacobson’s model, there is a significant increase in hydropower capacity – up to 1,300 gigawatts (or about 10 times current capacity), which appears to run for at least 12 hours straight in some days of the model output. Jacobson says this is possible by installing more turbines and generators at existing dams, just not using them very often. </p>
<p>But dams are built with specific maximum flow rates because if you let too much water flow through a dam, you can flood areas downriver. Jacobson has since admitted that providing this much extra power from existing dams <a href="https://twitter.com/mzjacobson/status/877340327601815554">would be hard</a>. </p>
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<p>I recently took a tour of Hoover Dam. One of the first things they tell you is that the dam was built for irrigation and flood control, and that electricity production is a nice side product. So expecting that dams in the country could boost their output might be harder than the analysis implies. </p>
<h2>Implausible assumptions</h2>
<p>Clack questions a long list of input assumptions of Jacobson’s model. A number are related to how quickly technologies can mature and be used at large scale, including underground thermal energy storage, phase change materials to store solar thermal energy, and hydrogen as a usable fuel. Other critiques focus on assumptions around how flexible the demand for energy can be – a key consideration when dealing with variable sun and wind power. Then there’s the amount of electric transmission power infrastructure needed, the costs of all the capital required, the pace of investment needed and land use issues.</p>
<p>Some criticisms are probably fair. I tend to be bullish on the potential of technology to advance rapidly, but having worked in residential energy use, and energy retrofits in particular, I find the amount of <a href="http://large.stanford.edu/courses/2013/ph240/lim1/">geothermal energy storage retrofits</a> for heating and air-conditioning in buildings Jacobson assumed hard to fathom. </p>
<p>I have some reservations on the ability of 67 percent of demand to be flexible. I also have some questions on the pace of investment required in Jacobson’s scenario.</p>
<h2>Insufficient power system modeling</h2>
<p>Clack attacks LOADMATCH, the power system model in Jacobson’s analysis, as being too simplistic. The main criticism of LOADMATCH is that it does not consider <a href="https://en.wikipedia.org/wiki/Utility_frequency">frequency regulation</a> – the need to keep the frequency of the power grid steady at 60 Hz, which is a very important aspect of keeping the power supply reliable. </p>
<p>One piece of anecdotal information: Jacobson states in the paper Supplementary Information that it takes LOADMATCH about three to four minutes to simulate an entire year. Our simulations of just the Texas electricity market can take hours to run, and can take significantly longer for simulations of high levels of renewables. </p>
<p>After reading both papers, both supplementary information sections, the counter-rebuttal, a lot of news articles and tweetstorms (from other energy folks I trust), I find myself thinking that the burden of proof is still in Jacobson’s court. There are many lessons to learn here.</p>
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<p>But, in the end, my view is that the body of scientific understanding will be stronger for it. The peer review process is slow, uses imperfect human volunteers and doesn’t always get it exactly right the first time. The list of authors on the Clack rebuttal is impressive, and should be paid attention to. However, if Jacobson’s work can survive this challenge, I figure it will stand the test of time.</p><img src="https://counter.theconversation.com/content/79834/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joshua Rhodes abides by the disclosure policies of the University of Texas at Austin. The University of Texas at Austin is committed to transparency and disclosure of all potential conflicts of interest. He has filed all required financial disclosure forms with the university. Joshua Rhodes has not received any research funding that would create a conflict of interest or the appearance of such a conflict. In addition to research work on topics generally related to energy systems at the University of Texas at Austin, Joshua Rhodes is an equity partner in IdeaSmiths LLC, which consults on topics in the same areas of interests. The terms of this arrangement have been reviewed and approved by the University of Texas at Austin in accordance with its policy on objectivity in research.</span></em></p>How fast can the US transition to clean energy and with what energy sources? Here’s why an impassioned debate among energy wonks matters to the rest of us.Joshua D. Rhodes, Postdoctoral Researcher of Energy, The University of Texas at AustinLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/524842017-03-21T01:03:44Z2017-03-21T01:03:44ZDoes ‘green energy’ have hidden health and environmental costs?<figure><img src="https://images.theconversation.com/files/159210/original/image-20170302-14690-o29d4o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Wind turbines require massive structures that are polluting to produce and can harm ecosystems, but these impacts compare favorably with those of fossil alternatives.</span> <span class="attribution"><span class="source">www.shutterstock.com</span></span></figcaption></figure><p>There are a number of available low-carbon technologies to generate electricity. But are they really better than fossil fuels and nuclear power? </p>
<p>To answer that question, one needs to compare not just the emissions of different power sources but also the <a href="https://doi.org/10.1088/1748-9326/aa6047">health benefits and the threats to ecosystems</a> of <a href="http://www.resourcepanel.org/reports/green-energy-choices-benefits-risks-and-trade-offs-low-carbon-technologies-electricity">green energy</a>.</p>
<p>Production of electricity is responsible for about <a href="https://www.epa.gov/ghgemissions/global-greenhouse-gas-emissions-data">a quarter</a> of global greenhouse gas emissions, and demand is poised to rise as <a href="http://iopscience.iop.org/article/10.1088/1748-9326/8/2/024015">underserved populations connect to the grid</a>, and electronics and <a href="http://www.conservationmagazine.org/2016/09/evs-will-green-despite-increasing-power-demand/">electric vehicles</a> proliferate. So stopping global warming will require a transformation of electricity production. </p>
<p>But it is important to avoid various environmental pitfalls in this transition, such as disrupting ecosystems and wildlife or causing <a href="https://www.nytimes.com/2017/02/14/world/asia/indias-air-pollution-rivals-china-as-worlds-deadliest.html?ref=world">air pollution</a>.</p>
<p>In a <a href="http://dx.doi.org/10.1088/1748-9326/aa6047">research paper</a>, we analyzed the impact of electricity generation from renewable sources, <a href="https://en.wikipedia.org/wiki/Nuclear_power">nuclear fission</a> power plants and fossil fuels, with and without <a href="https://en.wikipedia.org/wiki/Carbon_capture_and_storage">CO₂ capture and storage</a> (CCS) technology for separating CO₂ and storing it underground. We accounted for the environmental effects associated with the production, operation and dismantling of facilities, as well as the production, transport and combustion of fuels. We then compared a baseline scenario to a <a href="http://www.iea.org/publications/scenariosandprojections/">low-carbon electricity scenario</a> that would prevent global average temperatures from rising more than two degrees Celsius above preindustrial levels by 2050 – the <a href="http://newsroom.unfccc.int/unfccc-newsroom/under-2-mou-a-subnational-global-climate-leadership/">point</a> climate scientists say will avoid dangerous climate change. </p>
<p>Our study emphatically confirms that fossil fuels – mainly coal – <a href="https://theconversation.com/why-coal-fired-power-stations-need-to-shut-on-health-grounds-68809">place a heavy burden on the environment</a> and that most renewable power projects have lower pollution-related impacts on ecosystems and human health. Nonetheless, no energy source is without adverse environmental side effects. Power plant siting, project design and technology choice are critical issues that investors and governments should consider very carefully.</p>
<h2>Solar shines</h2>
<p>Replacing fossil fuel power plants with renewable energy sources, including solar, wind, hydropower and geothermal power, would reduce diverse types of pollution. The magnitude of difference in pollution between fossil and some renewable energy options is stunning. For example, we found that the entire process of manufacturing, setting up and operating photovoltaic panels causes less pollution than only delivering fuel to a coal-fired power plant when mining is included.</p>
<p>What about the environmental footprint of actually making renewable energy systems?</p>
<p>Photovoltaics (PV) comes out very well in our analysis. Today, the production of PV cells uses much less energy than previously. The carbon emissions per unit of PV electricity is one-tenth or less of even the most efficient natural gas power plants. Human health problems, such as respiratory disease from particulate matter exposure, are around one-tenth of those of modern coal-fired power plants with advanced pollution control equipment. Similar conclusions hold for water and soil pollution on ecosystems, we found.</p>
<p>But solar panels require much more space to generate the same amount of power as fossil fuel or nuclear power generators. Shouldn’t covering huge areas with solar panels be a problem? Not necessarily. The amount of land needed to generate a kilowatt-hour from PV is comparable to that of coal power, when the land associated with mining coal is accounted for. And about half of the PV installations in our future scenario in 2050 could be placed on rooftops. </p>
<p>Producing PV panels does require various metals, many of which are produced only in <a href="http://e360.yale.edu/features/a_scarcity_of_rare_metals_is_hindering_green_technologies">limited locations</a>. Some of those metals are highly toxic. Waste treatment and recycling, which we did not include in our assessment, are therefore important. </p>
<p>PV, of course, delivers electricity only when the sun shines. However, a different solar technology – <a href="http://www.eia.gov/energyexplained/?page=solar_thermal_power_plants">concentrating solar-thermal power</a>, which concentrates light to make heat – may be a viable way forward as it delivers a similar performance in terms of pollution reduction yet offers the option to store heat and thus generate electricity in the evening. We assumed CSP technology, which currently has very low adoption compared to PV, would provide one quarter of solar electricity in our low-emissions scenario.</p>
<p>Environmental effects from hydropower vary widely, we found. <a href="https://www.washingtonpost.com/news/energy-environment/wp/2016/09/28/scientists-just-found-yet-another-way-that-humans-are-creating-greenhouse-gases/?utm_term=.80b2d0eb8462">Some dams cause significant climate impacts</a> through the emissions of methane from the decomposition of biomass in reservoirs. Other dams <a href="http://theconversation.com/chinese-hydropower-electrifies-southeast-asia-but-at-a-cost-20275">cause equally serious ecological problems</a> through habitat destruction. They can also block the migration of aquatic species and reduce sediment flow and nutrient transport, which affects floodplains and deltas. On the other hand, reservoirs form new habitats for birds and other species. </p>
<p>Hydropower offers a good illustration of the importance of site selection and project design. Some projects may be economically viable but ultimately should not be realized if society considers the environmental degradation they can cause. For other projects, the impacts can be limited by mitigation strategies such as <a href="https://en.wikipedia.org/wiki/Environmental_flow">environmental stream flow</a> and <a href="http://adventure.howstuffworks.com/outdoor-activities/fishing/fish-conservation/fish-populations/fish-ladder.htm">fish ladders</a>, which provide a detour for migrating fish around a dam.</p>
<p>Similar lessons hold for wind power, where habitat destruction during construction should be minimized and operations adjusted in order to reduce <a href="http://theconversation.com/what-can-be-done-to-make-sure-that-wind-energy-and-africas-vultures-co-exist-43677">collisions with raptors and bats</a>. Also, wind power resources vary widely across locations, which argues for choosing locations where wind resources are more abundant.</p>
<h2>Bioenergy threatens biodiversity</h2>
<p><a href="https://theconversation.com/does-bioenergy-have-a-green-energy-future-in-the-us-46921">Biomass</a> energy, or burning plant material for power generation, plays a central role in most plans to limit global warming to 2°C above preindustrial levels. Contrary to PV and wind, it provides on-demand renewable power. </p>
<p>When combined with CO₂ capture and storage, it can <a href="http://roadtoparis.info/2015/03/30/will-negative-emissions-technology-get-us-to-2-degrees/">scrub carbon from the atmosphere</a> and place it underground. Burning short-rotation coppice, such as <a href="https://en.wikipedia.org/wiki/Willow">willow</a> and <a href="https://en.wikipedia.org/wiki/Miscanthus">miscanthus</a>, to produce power can also lower the net greenhouse gas emissions of biopower. In these ways, the health effects of burning biomass can be reduced. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/159649/original/image-20170306-20739-ndp41q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/159649/original/image-20170306-20739-ndp41q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/159649/original/image-20170306-20739-ndp41q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=464&fit=crop&dpr=1 600w, https://images.theconversation.com/files/159649/original/image-20170306-20739-ndp41q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=464&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/159649/original/image-20170306-20739-ndp41q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=464&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/159649/original/image-20170306-20739-ndp41q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=583&fit=crop&dpr=1 754w, https://images.theconversation.com/files/159649/original/image-20170306-20739-ndp41q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=583&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/159649/original/image-20170306-20739-ndp41q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=583&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Making power from bioenergy, such as wood chips, has carbon emissions and other air pollutants. Capturing carbon and pumping it underground improves its environmental footprint.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/oregondepartmentofforestry/14492838086/in/photolist-o5FzQJ-6nMQsW-qwseB3-cdkAAA-jyk1zr-5EyEX5-eQcjHd-9zfV7t-uTTQbQ-uMzvr-4U6RhP-pi2dzd-b7qmzi-65BCRS-4hSLAU-5PgquD-5Eun9i-5Eun8p-wRJo5b-4nc9yY-4wGdak-5Eunaz-aFH8GZ-gZkD9y-65Q7Uj-gZkCjs-da7GXg-ntxXWi-6HLrvg-dGRmwy-khJSXc-asqZKX-dn3KpF-gZkqEN-GWQS5-7Jf5TG-adHke6-6ExLU7-ppYB1B-sdRq54-5ZoWAR-9cjB84-pPMK2a-9Vx44H-6baKir-8cgdFs-7gZnwu-q2DvZU-ebxED4-oNTPC">Oregon Department of Forestry</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Yet, the land use required to grow even these fast-growing plants dwarfs the land use of other power sources. This has significant ecological implications. As measured by species lost per kilowatt-hour generated, we found that the ecological damages of biomass are comparable to that of coal and gas. </p>
<p>So while it does deliver benefits from reduced greenhouse gas emissions, biomass power becomes more favorable to ecosystems only when used <a href="https://en.wikipedia.org/wiki/Bio-energy_with_carbon_capture_and_storage">with carbon capture and storage</a>, we concluded.</p>
<p>Climate mitigation strategies can provide a rare opportunity to reduce not only carbon emissions but also a wide range of environmental problems. However, deployment of low-carbon technologies should avoid sensitive habitats in order to fully realize their environmental benefits without triggering unintended consequences. </p>
<p>While most people recognize that solar and wind are low-carbon energy sources, bioenergy and carbon capture and storage also have an indispensable role in basically all scenarios where countries rapidly reduce carbon emissions. Our results indicate that we need to search for ways to use these technologies while minimizing the harm to ecosystems. It is not just about whether we employ clean energy, but what technologies, where and how. </p>
<p><em>This article was updated on May 2, 2022 to remove an image that infringed on copyright.</em></p><img src="https://counter.theconversation.com/content/52484/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Edgar Hertwich has received funding from the Research Council of Norway and United Nations Environment Programme. He is a member of the International Resource Panel and president of the International Society for Industrial Ecology. </span></em></p><p class="fine-print"><em><span>Anders Arvesen receives funding from the Research Council of Norway. </span></em></p><p class="fine-print"><em><span>Thomas Gibon received funding from the Research Council of Norway to carry out his doctoral thesis. </span></em></p><p class="fine-print"><em><span>Sangwon Suh does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>No energy source is perfect, but solar and wind have a much lower health and environmental footprint than fossil fuels, a study finds. Biopower, though, is a mixed bag.Edgar Hertwich, Professor in Industrial Ecology, Norwegian University of Science and TechnologyAnders Arvesen, Researcher in Energy and Process Engineering, Norwegian University of Science and TechnologySangwon Suh, Professor in Industrial Ecology, University of California, Santa BarbaraThomas Gibon, Research and Technology Associate, Norwegian University of Science and TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/661112016-10-19T01:02:35Z2016-10-19T01:02:35ZClinton says the ‘clean energy economy’ will create millions of jobs. Can it?<p>Job growth is a prime topic in the U.S. presidential race, but Donald Trump and Hillary Clinton have very different takes on the role clean energy could play in creating employment. </p>
<p>Democratic hopeful Hillary Clinton says the U.S. can be the world’s “clean energy superpower.” Her plan, <a href="https://www.hillaryclinton.com/briefing/factsheets/2016/10/10/hillary-clintons-plan-for-combatting-climate-change-and-making-america-the-clean-energy-superpower-of-the-21st-century/">spelled out in detail online</a>, would create millions of jobs and spur billions of dollars in public and private investment, while making infrastructure more resilient and lowering emissions. </p>
<p>Republican candidate Donald Trump says he’s a “great believer in all forms of energy” but that the country’s energy policies are a “<a href="https://www.washingtonpost.com/news/the-fix/wp/2016/09/26/the-first-trump-clinton-presidential-debate-transcript-annotated/">disaster</a>.” In a 2015 <a href="http://www.cnn.com/2015/09/24/politics/donald-trump-pope-francis-immigration-climate-change/">interview with CNN</a>, Trump said policies to support clean energy and reduce carbon emissions would “imperil jobs” and “the middle class and lower classes.” </p>
<p>Like many critics of the federal government’s efforts to promote clean energy, he points to the failure of Solyndra as a waste of taxpayer money. Solyndra, you may recall, was a solar company that received a partial loan guarantee from the U.S. government but went bankrupt in 2011, defaulting on a US$535 million loan.</p>
<p>What does economic research say about the potential of government-led industrial policy to promote clean energy and create jobs? Looking at the American Recovery and Reinvestment Act (ARRA) of 2009, or what came to be known as the “stimulus package,” provides us some insights. What clearly emerges is that the expansion of renewable energy is an opportunity to create jobs in manufacturing and construction, as well as in other industries.</p>
<h2>Ghosts of Solyndra</h2>
<p>I was a coauthor of the 2014 <a href="http://www.peri.umass.edu/236/hash/fe657f2845f6a5b56a37f3cb8bed92e8/publication/626/">“Green Growth”</a> study by the Political Economy Research Institute (PERI) at the University of Massachusetts Amherst. The Brookings Institution did its own study in 2011, <a href="https://www.brookings.edu/research/sizing-the-clean-economy-a-national-and-regional-green-jobs-assessment/">“Sizing the Clean Energy Economy.”</a> Both of these studies find that renewable energy and energy efficiency industries are engines of job growth, and that public support for these industries catalyzes private investments and spurs economic growth overall.</p>
<p>Yet the academic research is often overlooked or pushed aside in the public discourse, as so-called “failures” such as Solyndra’s bankruptcy are held up as examples of failed clean energy policies. In fact, public policies for clean energy have largely been effective in stimulating the growth of this sector, as well as the creation of new jobs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/142072/original/image-20161017-12447-1q09jgj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/142072/original/image-20161017-12447-1q09jgj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/142072/original/image-20161017-12447-1q09jgj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=390&fit=crop&dpr=1 600w, https://images.theconversation.com/files/142072/original/image-20161017-12447-1q09jgj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=390&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/142072/original/image-20161017-12447-1q09jgj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=390&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/142072/original/image-20161017-12447-1q09jgj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=490&fit=crop&dpr=1 754w, https://images.theconversation.com/files/142072/original/image-20161017-12447-1q09jgj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=490&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/142072/original/image-20161017-12447-1q09jgj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=490&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The stimulus funded a number of utility-scale renewable energy projects, including the Shepherds Flat Wind Farm, one of the largest wind farms in the world.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/locosteve/6171921757/">locosteve/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Let’s first look specifically at the Department of Energy’s (DOE) Loan Guarantee program which was funded as part of the stimulus and provided a loan to Solyndra to build a factory. On the whole, this <a href="http://energy.gov/lpo/portfolio-projects">program</a> was hugely <a href="http://www.energy.gov/sites/prod/files/RecoveryActSuccess_Jan2012final.pdf">successful</a>. </p>
<p>It was responsible for advancing the renewable energy business by financing the world’s largest solar photovoltaic plant, supporting two of the world’s largest solar thermal projects, and financing the world’s largest wind farm as of 2012. What’s more, losses such as Solyndra accounted for only two percent of the entire portfolio of lending, a staggeringly small figure when compared to typical loss rates in venture capital, often on the order of <a href="http://www.forbes.com/forbes/welcome/?toURL=http://www.forbes.com/sites/brucebooth/2012/11/07/data-insight-venture-capital-returns-and-loss-rates/&refURL=&referrer=#340d916a4408">40 or 50 percent</a>. </p>
<p>And for the American taxpayer, the losses are actually nonexistent, because the interest earned on the successful loans made by the DOE now exceeds the losses from companies like Solyndra. By the end of 2014, the DOE had already received <a href="http://energy.gov/sites/prod/files/2014/11/f19/DOE-LPO-Financial%20Performance%20November%202014.pdf">$810 million in interest, in comparison to the $780 million in losses</a>. </p>
<h2>Renewable and efficiency versus fossil</h2>
<p>The sort of activity funded by the Loan Guarantee Program (which provides financing to automakers, electric utilities and other industries) creates jobs. And the clean energy industry is one of the fastest growing areas in the global economy. </p>
<p>In March 2016, <a href="http://www.bloomberg.com/news/articles/2016-05-25/clean-energy-jobs-surpass-oil-drilling-for-first-time-in-u-s">Bloomberg</a> reported that jobs in the solar energy industry had grown 12 times faster than overall global job growth. The U.S., near the top of the pack behind China and Brazil, already has more than three-quarters of a million jobs in clean energy, defined as jobs related to solar, wind, bioenergy and geothermal. </p>
<p>But how about the claim that pro-renewable energy policies cause job losses in fossil fuels? </p>
<p>Studies such as the PERI “Green Growth” report show that a transition from fossil fuels to clean energy does, in fact, create jobs. Lots of them. For example, for every $1 million spent on energy efficiency about 15 jobs are created. These include the “direct” jobs in manufacturing and installation, as well as the “indirect” jobs created through the supply chain, in industries such as engineering, accounting, trucking, and many others. Overall, renewable energy and energy efficiency, the report finds, creates about 13 jobs per $1 million of spending. </p>
<p>Meanwhile, fossil fuels create fewer jobs for the same amount of spending, supporting about six jobs per $1 million for ongoing operations in the industry, or about 11 jobs for the creation of new fossil fuel production. There are a few reasons why clean energy creates more jobs than fossil fuels: labor intensity, domestic content and wages. </p>
<p>Labor intensity means that more of the total spending goes toward hiring workers rather than for capital, such as buildings and equipment. The oil and gas industry is one of the most capital-intensive industries in the economy, producing fewer jobs for each $1 million of spending. </p>
<p>Clean energy also has higher domestic content – including construction labor and manufactured components – than fossil fuels, meaning that more of the inputs come from within the U.S., and so that’s where more of the jobs are created. And finally, average wages are slightly lower in the clean energy industry than the fossil fuel industry, so a given $1 million of spending can support more jobs in clean energy. </p>
<p>The PERI study finds that an investment on the order of 1.2 percent of U.S. GDP would create over four million jobs in clean energy, or close to three million net new jobs if we subtract the job losses in fossil fuels. </p>
<h2>Infrastructure upgrade</h2>
<p>And how does government spending on clean energy affect our energy system? The American Recovery and Reinvestment Act of 2009 (ARRA) was the largest public investment in clean energy in the history of the US. Of the approximately $800 billion package, $90 billion was targeted toward clean energy.</p>
<p>In February 2016, the Council of Economic Advisers (CEA), which is an agency that informs the president on economic policy, released their assessment of the impacts of the clean energy portions of the ARRA, <a href="https://www.whitehouse.gov/sites/default/files/page/files/20160225_cea_final_clean_energy_report.pdf">“A Retrospective Assessment of Clean Energy Investments in the Recovery Act.”</a> The CEA’s report shows the distribution of the approximately $90 billion funding for clean energy, which includes: </p>
<ul>
<li>renewable energy generation (29 percent of the total funding), </li>
<li>energy efficiency (22 percent), </li>
<li>transit (20 percent), </li>
<li>grid modernization (10 percent), </li>
<li>smaller amounts to green job training, R&D, carbon capture and storage, and clean energy manufacturing, among others.</li>
</ul>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/142075/original/image-20161017-12447-1tefbwd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/142075/original/image-20161017-12447-1tefbwd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/142075/original/image-20161017-12447-1tefbwd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=698&fit=crop&dpr=1 600w, https://images.theconversation.com/files/142075/original/image-20161017-12447-1tefbwd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=698&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/142075/original/image-20161017-12447-1tefbwd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=698&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/142075/original/image-20161017-12447-1tefbwd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=877&fit=crop&dpr=1 754w, https://images.theconversation.com/files/142075/original/image-20161017-12447-1tefbwd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=877&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/142075/original/image-20161017-12447-1tefbwd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=877&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The stimulus funding went toward energy infrastructure upgrades, including smart meters which are designed to speed up reading and restore power faster after outages.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/dukeenergy/3620050562/in/photolist-6vTGUS-8ML8Wg-hQQRmB-bYUzZQ-bYUzSu-o5CG2a-bYUA33-ec11jL-bYUzVh-dvKmUs-bEGs6f-88CTTx-brE21B-brE2br-doMJ5m-imBekX-aFdgFP-cC6odq-bYUzMN-aiXLgV-8N2xDo-bdNTr6-ooTcDp-6w7g3F-7Cu4H8-f74RQa-7W4gow-6CD6VX-8MPazf-3RpReZ-9Uqi7T-q9EiG6-a1TLHC-8ML4MZ-5h8EZZ-rLix3X-bYUzYy-a6jPMv-8WUQSH-bTBbce-5mV4ji-bYUzRf-bYUzU7-8WURfx-bYUzPQ-6297aB-5mV4hg-phgMA3-5mZjkE-bYUzWE">dukeenergy/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>About half of the $90 billion was used for incentives or matching grants, increasing the impact of the stimulus. The CEA estimates that $46 billion in incentives leveraged an additional $150 billion in private and nonfederal spending. Thus, there was a combined amount of $240 billion in both public and private spending on clean energy innovation, development, and most notably deployment, or installation of, for instance, solar panels and smart electricity meters. </p>
<p>In addition to the jobs created, these investments helped to improve the energy infrastructure and get large-scale wind and solar projects in the ground.</p>
<h2>Valid criticism</h2>
<p>Supporters of a free-market economy say the government should not be in the business of “picking winners,” that the market should determine which energy businesses thrive or fail. However, particularly with emerging technologies, the government can play an important role in fostering research and innovation. </p>
<p>Companies that stand to lose a profit may not want to make a risky investment in a new technology. The government can diversify and lower its risk by investing in many different types of technologies at the same time. Some of these will fail, like Solyndra, but many others will succeed and ultimately will be produced and sold by private companies. </p>
<p>There is one criticism of the ARRA that holds validity, which is that it tried to do too much in a short amount of time. Never in history had such a large public investment been made in clean energy, and there were processes and programs that took time to be established. Because of administrative bottlenecks, job growth was slower than it otherwise could have been. </p>
<p>Critics of government spending on clean energy programs also argue the rapid spread of fracking has created many jobs in the oil and gas industry, and that regulations that support clean energy will stifle oil and gas economic activity. Yet the rationales for public spending on clean energy are many, including:</p>
<ul>
<li>Fossil fuels are underpriced, as they do not include the cost of the environmental damage they produce.<br></li>
<li>Increased reliance on clean energy increases our national security, as we rely less on imported fossil resources and reduce the need to protect them through war. </li>
<li>These investments lower greenhouse gas emissions and improve local air quality.</li>
</ul>
<p>Both public and private spending on clean energy are necessary to continue the rapid pace of growth in this sector. And we see from the evidence that public support for clean energy catalyzes private investment, together creating millions of jobs and opportunities for workers and businesses alike.</p><img src="https://counter.theconversation.com/content/66111/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Heidi Garrett-Peltier does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Will government policy to promote clean energy be disastrous or a boon? A close look at the 2009 stimulus, which plowed $90 billion into energy, can tell us a lot.Heidi Garrett-Peltier, Assistant Research Professor, UMass AmherstLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/532202016-04-24T14:01:59Z2016-04-24T14:01:59ZDo wind vent holes in banners make a difference? We used a wind tunnel to find out<p>The next time you see a banner hung across a street or from a bridge, or hoisted as part of a street march, protest or demonstration, take a closer look. You may see that the banner has holes or slits cut into it.</p>
<p>But why would someone cut holes into a perfectly good banner?</p>
<p>These are so-called “wind vents”, and for some reason people have been mutilating their banners with these holes in the belief that their presence will significantly reduce the wind loading on the banner.</p>
<p>But does a banner with holes or slits really have an easier time in the wind than an equivalent banner that is hole free?</p>
<h2>History and legislation</h2>
<p>It is not known when people started to cut holes into their banners. There is very little written about the practice, and much of the knowledge appears to come via word of mouth or has been transferred from other wind related domains.</p>
<p>What is obvious from the <a href="http://www.simplysignsandbanners.com/1/post/2011/05/wind-slits-are-they-effective.html">websites of the world’s sign and banner makers</a> is that they are <a href="http://boeksigns.com/banner-wind-vents/">frustrated with having to cut holes into their lovingly-made creations</a>.</p>
<p>Some banner makers <a href="https://www.esigns.com/wind-slits.html">simply refuse</a>, and tell their customers that if they want holes, then they can cut them themselves.</p>
<p>The apparent importance of banner wind vents has led some local governments around the world to make them mandatory for banners installed in certain locations. No vent holes, no banner allowed!</p>
<p>The <a href="http://www.brisbane.qld.gov.au/laws-permits/laws-permits-businesses/light-brisbane-hang-bridge-banner/lighting-banner-packages/guidelines-hanging-bridge-banner">regulations of the Brisbane City Council</a>, in Queensland, Australia, state that for banners to be installed on the city’s iconic Story Bridge, they “must be provided with wind vent holes” and that “wind holes (vents) need to be spaced at approx. 3m intervals”.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/116452/original/image-20160325-17859-p641wg.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/116452/original/image-20160325-17859-p641wg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/116452/original/image-20160325-17859-p641wg.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=169&fit=crop&dpr=1 600w, https://images.theconversation.com/files/116452/original/image-20160325-17859-p641wg.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=169&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/116452/original/image-20160325-17859-p641wg.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=169&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/116452/original/image-20160325-17859-p641wg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=212&fit=crop&dpr=1 754w, https://images.theconversation.com/files/116452/original/image-20160325-17859-p641wg.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=212&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/116452/original/image-20160325-17859-p641wg.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=212&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Brisbane City Council’s Story Bridge banner design guide indicating location of ‘wind vent holes’.</span>
<span class="attribution"><span class="source">Brisbane City Council design guide</span></span>
</figcaption>
</figure>
<p>The small town of Springville, Utah, USA, states in <a href="http://www.springville.org/wp-content/uploads/2015/03/BannerInfoAppPacket.pdf">its regulations</a> that at least 20% of the area of the banner must be made up of holes. It suggests “half moon shaped vents 4-6 inches wide and facing down throughout the banner”.</p>
<h2>Understanding the aerodynamics</h2>
<p>To understand what, if anything, wind vents do for our banners, we need to visit the work of aerodynamics specialists.</p>
<p>In 1956, B. G. de Bray, an aerodynamics expert at the UK’s Royal Aircraft Establishment, performed <a href="http://naca.central.cranfield.ac.uk/reports/arc/cp/0323.pdf">a series of wind tunnel tests</a> to show how flat plates with holes in them performed in a moving air stream. He was interested in how plates could be used for airbrakes on aircraft as they land.</p>
<p>His experiments showed that perforations (holes) make the air flow more stable but that there was “only a comparatively small reduction in drag coefficient”. He shows a graph recording the relationship between the area of the holes and the change in drag coefficient of a flat plate. The graph indicates that making 20% of a banner’s area holes will reduce the drag by around 5% in a wind of 150km/h.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/116451/original/image-20160325-17840-10iy0tz.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/116451/original/image-20160325-17840-10iy0tz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/116451/original/image-20160325-17840-10iy0tz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=251&fit=crop&dpr=1 600w, https://images.theconversation.com/files/116451/original/image-20160325-17840-10iy0tz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=251&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/116451/original/image-20160325-17840-10iy0tz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=251&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/116451/original/image-20160325-17840-10iy0tz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=316&fit=crop&dpr=1 754w, https://images.theconversation.com/files/116451/original/image-20160325-17840-10iy0tz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=316&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/116451/original/image-20160325-17840-10iy0tz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=316&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">These figures are taken from de Bray’s 1956 work on wind tunnel testing of flat plates with holes and how drag relates to hole area in a 150km/h wind. Note that CD designates the drag coefficient, which is a normalised way of representing force that accounts for plate size (or in our case the banner) and wind speed. Doing this allows the wind tunnel data to be scaled to full-size.</span>
</figcaption>
</figure>
<p>When we consider de Bray’s other finding – that holes do make the air flow more stable – we can look at a common example of this in action in round parachutes.</p>
<p>Billowing structures that fill with air on the windward side, such as round parachutes, become unstable when there are no holes in the structure. The air tends to spill almost randomly from the structure’s edge. This makes the structure flap around in the wind in a seemingly random manner.</p>
<p>This was discovered in the early days of parachute development. In the late 1700s, a number of parachute developers were killed due to accidents relating to their unstable and oscillating chutes.</p>
<p>In 1804, Frenchman Joseph Lelandes invented the apex vent, a hole in the top of the parachute. This appeared to solve the problem of stability but did not appear to reduce the drag, ideal for parachuting where you need the drag.</p>
<p>Since then there have been many studies showing the <a href="http://www.hindawi.com/journals/isrn/2013/320563/">benefits of holes in round parachutes</a>. One group even found during their <a href="https://www.wpi.edu/Pubs/E-project/Available/E-project-042407-112440/unrestricted/Brighenti_Duffen_Head_Vented_Parachutes_MQP.pdf">experiments</a> that vent holes in round parachutes slightly increase the drag on the chute while making it more stable.</p>
<h2>Wind tunnel tests</h2>
<p>Following in de Bray’s footsteps, we decided to turn to wind tunnel experiments to assess just how much impact those holes had on wind forces. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/sIS3Ujk3ytw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>We conducted a series of simple experiments where we put scaled versions of banners in a wind tunnel and measured the wind forces. We did this for a range of wind speeds and number of vents (holes). We then measured how the forces changed from test to test.</p>
<p>We performed experiments where vents were rectangular holes cut in the fabric and others where the vents were rectangular holes cut on three sides and allowed to hinge at the top (flaps).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/119728/original/image-20160421-27001-jv64yi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/119728/original/image-20160421-27001-jv64yi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/119728/original/image-20160421-27001-jv64yi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=642&fit=crop&dpr=1 600w, https://images.theconversation.com/files/119728/original/image-20160421-27001-jv64yi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=642&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/119728/original/image-20160421-27001-jv64yi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=642&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/119728/original/image-20160421-27001-jv64yi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=807&fit=crop&dpr=1 754w, https://images.theconversation.com/files/119728/original/image-20160421-27001-jv64yi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=807&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/119728/original/image-20160421-27001-jv64yi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=807&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A test banner with 7% of its area made of holes in the wind tunnel.</span>
<span class="attribution"><span class="source">Author supplied</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/119750/original/image-20160422-27007-9magqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/119750/original/image-20160422-27007-9magqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/119750/original/image-20160422-27007-9magqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/119750/original/image-20160422-27007-9magqg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/119750/original/image-20160422-27007-9magqg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/119750/original/image-20160422-27007-9magqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/119750/original/image-20160422-27007-9magqg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/119750/original/image-20160422-27007-9magqg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">As for above, but showing a banner with 7% porosity and hinged flaps.</span>
<span class="attribution"><span class="source">Author supplied</span></span>
</figcaption>
</figure>
<p>Experimental wind speeds tested ranged from approximately 25km/h to 100km/h and the range of vent hole area to total banner area ratios (porosity) assessed was from zero (no holes in the banner) to approximately 20%, which coincides with the Springville regulations and makes a pretty holy banner.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/119742/original/image-20160422-26976-z94hoe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/119742/original/image-20160422-26976-z94hoe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=497&fit=crop&dpr=1 600w, https://images.theconversation.com/files/119742/original/image-20160422-26976-z94hoe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=497&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/119742/original/image-20160422-26976-z94hoe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=497&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/119742/original/image-20160422-26976-z94hoe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=624&fit=crop&dpr=1 754w, https://images.theconversation.com/files/119742/original/image-20160422-26976-z94hoe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=624&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/119742/original/image-20160422-26976-z94hoe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=624&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A plot showing drag on the banner versus porosity of the banner for the 100km/h tests over the range of banner porosities. The vertical axis shows the drag coefficient (CD) ratio, which is the wind force measured on the porous banner divided by the wind force on the solid banner. A porosity of 0.1 is 10% holes/vents/flaps.</span>
<span class="attribution"><span class="source">Author supplied</span></span>
</figcaption>
</figure>
<p>A value of 1 in the figure (above) would indicate that the vents have done nothing and a value of 0.9 would suggest there has been a 10% reduction in load.</p>
<p>It is clear that wind vents do reduce the wind load on a banner, but as de Bray showed, the reduction in load is relatively small until porosity becomes large.</p>
<p>The reduction in drag force is greater for holes and hinged flaps than found by de Bray (and others) for uniformly perforated plates or fabrics.</p>
<p>The wind speed makes a difference. At low wind speeds the presence of vents can actually increase the wind load on a banner, which in our test was found to be up to 5%.</p>
<p>In general though, force coefficients decreased as wind speeds increase. This was particularly the case for the banners with flaps, where these vents became more open as the wind speed increased.</p>
<p>So the type of vent makes a big difference. Banners with holes rather than hinged flaps experienced lower wind loads. Both of these vent types experience lower loads than on uniformly perforated plates, which perform similarly to porous mesh fabrics. </p>
<p>With these points in mind, we return to the Brisbane City Council’s regulations for placing banners on the Storey Bridge. It is now possible to calculate the effect of their prescribed wind vents.</p>
<p>If we assume that they would like holes, and the maximum size of a banner is 18m wide by 0.9m high, then our best guess estimate is a semi-circular hole radius of 25cm noting also that five wind holes are required. We calculate that at most, 3% of the banner will be holes.</p>
<p>Interpolating our figure this would give us a 2% reduction in wind load. A sign of 98% the area of the maximum would be 18m wide and 0.88m high and would only require you to trim 2cm off the bottom of the sign to create a sign of equivalent drag to the one with five holes in it! It hardly seems worth the effort.</p>
<h2>The verdict</h2>
<p>The science shows us that flat structures behave one way, and billowing air-filled structures behave a different way. It seems that our legislators have been confused and applied results from parachutes to flat banners.</p>
<p>If you have a banner tied in such a way that it will remain relatively flat in the wind, then it seems that the benefits of putting in vents are minimal unless you make your banner into Swiss cheese.</p>
<p>You are simply better off making a slightly small banner to achieve the same reduction in load.</p><img src="https://counter.theconversation.com/content/53220/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Mason receives funding from Australian Research Council and the Bushfire and Natural Hazards Cooperative Research Centre. </span></em></p><p class="fine-print"><em><span>Jonathan Roberts is an Associate Investigator with the Australian Centre for Robotic Vision and co-founder of the UAV Challenge flying robot competition. </span></em></p>Attend any ANZAC Day parade and you might see people carrying banners with holes cut in them. They’re supposed to cut any drag or wind resistance but do they do any good?Matthew Mason, Lecturer in Civil Engineering, The University of QueenslandJonathan Roberts, Professor in Robotics, Queensland University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/500472015-11-03T11:07:33Z2015-11-03T11:07:33ZAs US shutters aging nuclear plants, cutting emissions will become more costly<figure><img src="https://images.theconversation.com/files/100462/original/image-20151101-16554-m13igc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Losing steam? Older power plants are expensive to operate or upgrade.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/75012107@N05/6762402323/in/photolist-biz5Bv-9xbTFj-9wxbM3-9wxc2C-9wucoR-9wxcnm-9wxc8A-8g8H69-8g5r62-ne2PEF-ne31UJ-9xbKSd-3JpVg-nvyeiG-8g5rqi-ne2ZJN-9CmJ4u-4WaMqe-4Wf2Ks-7LMrQ-nveBjF-88TJfs-8JinVd-55nFyi-55rTvU-bHBT8P-8ip2r-nvfKsJ-dWZoAV-dX63Py-nvygT1-nttKCJ-3dJwD-4DUJu9-dWZoyB-9pQL3d-ne31Py-ne2Q7n-ne31iU-nvfMYq-nveCft-x3dDg-9xbXUq-9xQ7Qt-9dQa2-7x4wD-38QLPZ-4idF6u-4ZB4Kh-ne2UoQ">Montgomery County Planning Commission</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span></figcaption></figure><p>The United States is the world’s largest producer of nuclear power, but the country’s fleet of nearly 100 reactors is showing its age. </p>
<p>On November 2, the owner of a nuclear power station in New York <a href="http://www.prnewswire.com/news-releases/entergy-to-close-james-a-fitzpatrick-nuclear-power-plant-in-central-new-york-300170100.html">said</a> it will shut the plant down, which follows announcements of plant closures in Massachusetts, California, Florida and Wisconsin. This raises important questions for the US energy sector. The retirements reflect a set of economic challenges for nuclear power plants across the United States, and have important implications for climate change, energy costs and the reliability of the power grid.</p>
<p>Nuclear provides nearly 20% of the electricity in the United States, but the average plant is about 34 years old, and prospects for the future of many of these plants are murky, at best. While five new reactors are currently under construction in the US, the World Nuclear Association <a href="http://world-nuclear.org/info/Country-Profiles/Countries-T-Z/USA--Nuclear-Power/">estimates</a> that more than 10 older ones are currently at risk of closure. </p>
<p>The explanation for these retirements and the limited amount of new construction is simple: <a href="https://www.aeaweb.org/articles.php?doi=10.1257/jep.26.1.49">cost</a>. </p>
<p>Abundant and cheap natural gas coupled with the rapid expansion of wind power has limited increases in electricity prices, making it harder for some nuclear operators to justify continued operations or make expensive repairs. By 2020, the US Energy Information Administration <a href="http://www.eia.gov/forecasts/aeo/electricity_generation.cfm">estimates</a> that the cost of bringing new nuclear online will be about 25% more expensive than natural gas or wind.</p>
<p>But nuclear power is by far the most important source of non-CO2-emitting electricity in the United States. And while renewables like wind and solar have grown rapidly, they respectively <a href="http://www.eia.gov/electricity/data/browser/">accounted for</a> just 4% and 0.4% of US electricity generation in 2014. </p>
<p>So as the existing nuclear fleet ages and eventually retires, what will happen to domestic CO2 emissions?</p>
<h2>Regional picture</h2>
<p>If nuclear power were somehow replaced entirely by wind and solar, emissions would remain flat – a best-case scenario. </p>
<p>The US electricity system produces about <a href="http://www.eia.gov/electricity/annual/html/epa_09_01.html">500 tons of CO2</a> for every <a href="http://www.eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_1_1">gigawatt-hour of power generated</a>, and if all of today’s nuclear power were replaced by natural gas, total power sector CO2 emissions would grow by roughly 15%.</p>
<p>Take as an example Japan, which after the 2011 meltdown at Fukushima-Daiichi ordered all nuclear units closed. Nuclear power was replaced by coal, oil and gas-fired generation (the country also adopted increased energy-conservation measures). Most reactors are still offline, and Japanese CO2 emissions in 2014 were <a href="http://phys.org/news/2014-11-japan-co2-emissions-yearly-high.html">roughly 20% higher</a> than they were in 2010, the year before the earthquake.</p>
<p>But the story in the United States is more complicated; the effect on CO2 emissions when a nuclear plant closes varies substantially based on which part of the country you’re looking at.</p>
<p>That’s because some regions, notably <a href="http://www.arb.ca.gov/cc/capandtrade/capandtrade.htm">California</a> and <a href="http://www.rggi.org/">nine northeastern states</a>, produce and consume electricity under a cap-and-trade program (a <a href="https://www.congress.gov/bill/111th-congress/house-bill/2454">federal cap-and-trade bill</a> died in the Senate in 2009). These programs cap the amount of CO2 that can be emitted from power plants each year (California’s program also covers other energy sources like transportation fuels), charging emitters a price for each ton of CO2 they produce.</p>
<p>So when a nuclear plant shuts down in California or Massachusetts, the market finds a way to stay under the emissions cap by reducing demand, increasing efficiency, and adding new carbon-free sources like wind and solar. These measures require new investment, and raise the price of electricity.</p>
<p>But when a nuclear plant goes offline in Wisconsin or Florida, where there is no cap, there is no requirement for power producers to find a way to hold emissions steady. Instead, the electricity will be replaced by a combination of sources that is cheapest for that region, and because that cheapest option is often natural gas, CO2 emissions will rise.</p>
<h2>Wind and solar to rescue?</h2>
<p>Some will argue that nuclear power can be replaced quickly with wind and solar. </p>
<p>Indeed, these sources are growing rapidly in the United States, and in some places, they are competitive with other fuels like natural gas. But wind and solar power do not provide the type of steady, reliable base load that nuclear (and coal and gas) can. </p>
<p>Wind and solar produce power when the wind blows or the sun shines, and need to be backed up by a rock-solid “baseload” source of power, such as natural gas. Policies in some parts of the country have introduced <a href="http://www.utilitydive.com/news/pjm-auction-results-capacity-payments-to-plants-rise-37-in-bid-to-avoid-o/404480/">additional incentives</a> for providing reliable power, but these incentives have not been enough to ward off retirement for a number of aging nuclear plants. </p>
<p>The federal government has for decades supported nuclear power with the Price-Anderson Act, which <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1465-7287.1990.tb00645.x/abstract">limits operator’s liability</a> in case of accidents, and newer policies that <a href="http://www.world-nuclear.org/info/Country-Profiles/Countries-T-Z/USA--Nuclear-Power-Policy/">provide a tax credit</a> for new nuclear plants, <a href="http://www.energy.gov/articles/energy-department-issues-remaining-18-billion-loan-guarantees-vogtle-advanced-nuclear">loan guarantees</a> for new construction and more. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/100552/original/image-20151102-16532-1e3z1v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/100552/original/image-20151102-16532-1e3z1v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/100552/original/image-20151102-16532-1e3z1v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/100552/original/image-20151102-16532-1e3z1v1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/100552/original/image-20151102-16532-1e3z1v1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/100552/original/image-20151102-16532-1e3z1v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/100552/original/image-20151102-16532-1e3z1v1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/100552/original/image-20151102-16532-1e3z1v1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Wind power is competitive on price in some regions depending local prices and how good the wind is, but power generators will choose the lowest-cost option, which is natural gas, in most parts of the US.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/lawmurray/4367991464/in/photolist-7DZ6FE-pULMU5-dnNfp3-g5tPWB-qFwgtM-dbFQUD-8EHpqb-379p3x-37sNMc-37e4XQ-37xrWC-nMeVtq-4RuTfm-7pMwLr-sXmgPh-5gpG9c-4RuTGu-4EBXn-puKvPy-pyXBBY-e9DemK-6LREjS-kmu8nH-aKcaxr-nPRNGZ-bL6qEH-6A5nS-8nWN8J-yo3z1n-e9ruQr-dur1nU-duqZVf-dukp7K-dukisz-duqZ5s-duki88-dur1u5-duqZcu-duqXjU-eazuos-2VbpGa-8nSq5x-2Afg7n-fCN7ej-eatNpi-eazttG-eatN3g-eatMAr-eatPLk-eatNyz">lawmurray/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The Obama administration’s recently finalized Clean Power Plan requires utilities to lower their overall emissions through efficiency or using less polluting sources of power but it <a href="http://thebreakthrough.org/index.php/voices/energetics/clearing">does little</a> to create incentives to keep older reactors producing.</p>
<p>Absent a substantial change in policy, nuclear technology, or electricity prices, nuclear power plants will continue to face substantial economic challenges in the United States. </p>
<p>In the meantime, the location of retiring plants matters a great deal for CO2 emissions. In regions with cap-and-trade, nuclear retirements will likely raise power prices, but have little short-term effect on emissions, while regions without cap-and-trade are likely to see their CO2 emissions rise if and when plants close.</p>
<p>Looking forward, a better approach to limiting CO2 emissions would bring together the entire country, rather than leaving cap-and-trade programs to be implemented in some states but not others. </p>
<p>Analysts have known for years that this type of nationwide <a href="http://www.sciencedirect.com/science/article/pii/S0095069602000165">carbon pricing</a> needs to be <a href="http://www.sciencedirect.com/science/article/pii/S0095069607001064">the lynchpin</a> of any <a href="http://www.pnas.org/content/107/26/11721.full.pdf+html&">economically sound</a> climate policy.</p>
<p>The struggles of nuclear power will make it harder for the US to achieve its long-term climate goals, even though the falling costs of wind and solar power will provide a boost. </p>
<p>But without nationwide carbon pricing, there is <a href="https://theconversation.com/can-the-paris-climate-talks-prevent-a-planetary-strike-out-47017">no clear path</a> toward the levels of emissions reductions we need to prevent the worst impacts of climate change.</p><img src="https://counter.theconversation.com/content/50047/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daniel Raimi does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Anti-nuclear advocates may cheer the closing of nuclear power plants in the US, but thanks to cheap natural gas, less nuclear power means higher emissions.Daniel Raimi, Lecturer on Public Policy and Research Specialist, University of MichiganLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/419372015-06-12T10:18:06Z2015-06-12T10:18:06ZCould one million smart pool pumps ‘store’ renewable energy better than giant batteries?<figure><img src="https://images.theconversation.com/files/84611/original/image-20150610-6823-1sxzzu4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Lots of wind blowing – often at night when there's little demand for power.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/ncbob/3781036383/">ncbob/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>As more wind and solar energy comes online, the people who run the power grid have a problem: how do they compensate for the variable nature of the sun and wind?</p>
<p>California plans to spend <a href="http://www.npr.org/2013/12/23/250031679/could-big-batteries-be-big-business-in-california">billions of dollars</a> for batteries to even out the flow of power from solar and wind, much the way shock absorbers smooth out bumps on the road. But do they need to? Not at all!</p>
<p>In my <a href="http://www.slideshare.net/spmeyn/demandside-flexibility-for-reliable-ancillary-services?related=2">research</a>, I’ve found that we can accommodate a grid powered 50% by renewable energy without the use of batteries. </p>
<p>Systems flexible enough to accommodate the ups and downs of solar and wind production can be made by adjusting the power at millions of homes and businesses on a minute-by-minute or even second-by-second basis. This approach requires no new hardware, some control software and a bit of consumer engagement.</p>
<h2>Massive balancing act</h2>
<p>Already, electric power procured from the wind or sun is leading to large and small “bumps” in the energy fed to the grid. </p>
<p>For example, on a typical week in the Pacific Northwest, power can increase or decrease by more than one gigawatt in an hour. That’s the equivalent of the output from one huge nuclear power plant able to supply a million homes.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/84607/original/image-20150610-6804-ibc5b4.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/84607/original/image-20150610-6804-ibc5b4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/84607/original/image-20150610-6804-ibc5b4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=442&fit=crop&dpr=1 600w, https://images.theconversation.com/files/84607/original/image-20150610-6804-ibc5b4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=442&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/84607/original/image-20150610-6804-ibc5b4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=442&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/84607/original/image-20150610-6804-ibc5b4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=556&fit=crop&dpr=1 754w, https://images.theconversation.com/files/84607/original/image-20150610-6804-ibc5b4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=556&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/84607/original/image-20150610-6804-ibc5b4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=556&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Look at the green line. Wind power generation is volatile and not always in sync with the actual demand for power (red line, below the blue).</span>
<span class="attribution"><a class="source" href="http://transmission.bpa.gov/business/operations/Wind/baltwg.aspx">Bonneville Power Administration</a></span>
</figcaption>
</figure>
<p>This is an enormous challenge to grid operators in this region. Massive fluctuations in power require equally massive storage devices that can charge when the wind is blowing, and discharge during periods of calm. </p>
<p>Now, the balance of supply and demand for power is primarily done by generating more power rather than storage.</p>
<p>Grid operators draw on what is called the balancing reserves obtained from fossil fuel generators or hydro plants, when available. These power plants ramp up and down their output in response to a signal from a grid balancing authority. This is just one of many ancillary services required to maintain a reliable grid.</p>
<p>Many states are now scrambling to find new sources of ancillary services, and the federal government is also searching for incentives: Federal Energy Regulatory Commission (FERC) orders 745, 755 and 784 are recent responses by a government agency to create financial incentives for <a href="http://www.di.ens.fr/%7Ebusic/papers/HICSS48_Sept1.pdf">responsive resources to balance the grid</a>.</p>
<h2>Are batteries the solution?</h2>
<p>Storage is everywhere, but we have to think beyond electricity.</p>
<p>Consider a <a href="http://www.meyn.ece.ufl.edu/assets/uploads/2014/12/HVACtoGRID2014.pdf">large office building</a>. Will anyone notice if the fan power is reduced or increased by 10% for 10 or 15 minutes? This makes no demands on the comfort of occupants of the building, but the resulting deviations in power can provide a substantial portion of the needs of the grid. A building can be regarded as a virtual battery because of thermal inertia – a form of thermal storage.</p>
<p>What about for longer time periods? Residential pool pumps (as well as pumps used in irrigation) are a significant load in Florida and California – well over one gigawatt in each state – that can be run at different times of the day.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/84610/original/image-20150610-6798-qrg3up.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/84610/original/image-20150610-6798-qrg3up.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/84610/original/image-20150610-6798-qrg3up.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/84610/original/image-20150610-6798-qrg3up.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/84610/original/image-20150610-6798-qrg3up.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/84610/original/image-20150610-6798-qrg3up.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/84610/original/image-20150610-6798-qrg3up.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/84610/original/image-20150610-6798-qrg3up.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Turning down, or turning on, many of these = enough power smooth out solar and wind, while still cleaning the pool.</span>
<span class="attribution"><a class="source" href="http://pixabay.com/en/pump-pool-filter-water-pump-pool-318331/">Pixabay</a></span>
</figcaption>
</figure>
<p>Through local intelligence – in the form of a chip on each device or a home computer for many devices – the collection of one million pools in Florida can be harnessed as massive batteries. Through one-way communication, each pool will receive a regulation signal from the grid operator. The pool will change state from on to off based on its own requirements, such as recent cleaning hours, along with the needs of the grid. Just as in the office building, each consumer will be assured of desired service.</p>
<p>Pools are, of course, just one example of a hungry but flexible load.</p>
<p>On-off loads such as water pumps, refrigerators or water heaters require a special kind of intelligence so that they can accurately erase the variability created from renewable generation. Randomization is key to success: To avoid synchronization (we don’t want every pool to switch off at once), the local intelligence includes a specially designed “coin-flip”; each load turns on or off with some probability that depends on its own environment as well as the state of the grid.</p>
<p>It is possible to obtain highly reliable ancillary service to the grid, while maintaining strict bounds on the quality of service delivered by each load. With a smart thermostat, for example, indoor temperature will not deviate by more than one degree if this constraint is desired. Refrigerators will remain cool and reliable, and pools will be free of algae.</p>
<h2>Where do we go from here?</h2>
<p>We first must respect the amazing robustness of the grid today. </p>
<p>This is the result of ingenious control engineering, much like the automatic control theory that brought the first human to the moon and makes our airplanes so reliable today. We cannot pretend that we can transform the grid without partnering with the control and power engineers who understand the mysterious dynamics of the grid. Instabilities and blackouts occur when we are too aggressive in attempting to balance supply and demand, just as they occur when we are too slow to respond.</p>
<p>We are certain that the engineering challenges will be largely solved in the upcoming years – it is an exciting time for power!</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/84618/original/image-20150610-6796-ib511x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/84618/original/image-20150610-6796-ib511x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/84618/original/image-20150610-6796-ib511x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=166&fit=crop&dpr=1 600w, https://images.theconversation.com/files/84618/original/image-20150610-6796-ib511x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=166&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/84618/original/image-20150610-6796-ib511x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=166&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/84618/original/image-20150610-6796-ib511x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=208&fit=crop&dpr=1 754w, https://images.theconversation.com/files/84618/original/image-20150610-6796-ib511x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=208&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/84618/original/image-20150610-6796-ib511x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=208&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">“Intelligent” loads, or devices with controllers, can balance supply and demand of power along with generators and batteries.</span>
<span class="attribution"><span class="source">Author</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The next challenge is participation. </p>
<p>Today, about 750,000 homeowners in Florida have signed contracts with utility Florida Power & Light, allowing them to shut down pool pumps and water heaters in case of emergencies. How can we expand on these contracts to engage millions of homeowners and <a href="http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6483455&tag=1">commercial building operators</a> to supply the virtual storage needed? Recent FERC rules that offer payments for ancillary services for balancing the grid are a valuable first step in providing incentives.</p>
<p>It is possible that little incentive is required since we are not subjecting consumers to any loss of comfort: it is the pool or fridge that provides flexibility, and not the homeowner.</p>
<p>A sustainable energy future is possible and inexpensive with a bit of intelligence and flexibility from our appliances.</p><img src="https://counter.theconversation.com/content/41937/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sean Meyn receives funding from NSF, DOE, and Google.</span></em></p>Smoothing out variable wind and solar is a growing problem. Instead of storing energy with batteries, utilities can adjust the power of millions of devices in buildings and homes.Sean Meyn, Professor of Electrical and Computer Engineering, University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/405642015-04-21T07:13:19Z2015-04-21T07:13:19ZExplainer: the wild storms that lash Australia’s east coast<p>Over the past 24 hours, the Sydney, Central Coast, and Hunter regions of New South Wales have experienced very heavy rain, gale-force winds with gusts over 100 km per hour, and waves of more than 10 m in height. </p>
<p>For Sydney it was the wettest single day since February 2002, with 119.4 mm of rain recorded in the 24 hours to 9 am on April 21. Meanwhile, Tocal in the Hunter Valley recorded more than 100 mm in a single hour. Sadly, three deaths have been reported from flash flooding at Dungog. </p>
<p>So, what’s causing all this rain? </p>
<h2>The lowdown on lows</h2>
<p>In weather jargon, the words “cyclone” or “low” refer to an area where the pressure is lower than everywhere around it. </p>
<p>These can come in many forms – the most well-known are tropical cyclones, which develop where sea surface temperatures are warmer than 26.5C. </p>
<p>However, so-called “extra-tropical cyclones” are a frequent visitor to mid-latitudes around the world. Wherever they are, the strong pressure gradients and convergence of air in the centre can lead to strong winds, large waves, and heavy rainfall.</p>
<p>“East Coast Low” or “East Coast Cyclone” are terms we use for low-pressure systems that develop off the east coast of Australia, generally between Brisbane and eastern Victoria. </p>
<p>This area can experience several different types of low-pressure systems, including those that are formed from the remains of tropical cyclones that have moved southwards (such as <a href="http://www.bom.gov.au/climate/current/statements/scs44.pdf">Oswald</a> in January 2013) and large extra-tropical cyclones (such as the one that hit the Sydney-Hobart yacht race in December 1998) that form in the storm tracks to the south of the Australian mainland and move to positions off the east coast.</p>
<p>The classic East Coast Low often develops rapidly in surface troughs off the east coast, which is exactly what we saw this week. These lows are one of the hardest challenges for forecasters, as weather forecasting models can find it hard to decide exactly where these lows will form. </p>
<p>All three of these systems have different origins and they are very different synoptic systems, but have all been considered “East Coast Lows” in <a href="http://www.bom.gov.au/amoj/docs/2009/speer.pdf">at least one paper</a>, making the frequency of East Coast Lows depend largely on who you speak to. </p>
<h2>Is this a freak storm?</h2>
<p>In 2009, a group at the <a href="http://www.bom.gov.au/amoj/docs/2009/speer.pdf">Bureau of Meteorology</a> painstakingly searched every synoptic chart between 1970 and 2006, looking for all low-pressure systems along the east coast. They identified about 22 East Coast Lows each year. About seven of these each year caused widespread rainfall totals above 25 mm. </p>
<p>While lows are most common between May and August, they can occur at any time of year, with about every second April having a low that meets this 25-mm rainfall benchmark.</p>
<p>To some extent, it’s only the East Coast Lows that cause severe weather around the Sydney region that spark national interest. For example, two weeks ago a low caused heavy rain and strong winds along the south coast. A rapidly developing but short-lived East Coast Low also produced more than 100 mm of rain in Sydney over the 24 hours to 9 am on March 8, 2012, including 42.4 mm during the morning peak hour, causing widespread flash flooding. </p>
<p>Looking further back, many of the most severe weather events in Sydney and coastal NSW can be considered East Coast Lows. Several years ago we found that 60% of all major dam-filling events in Sydney catchments can be attributed to East Coast Lows, with several East Coast Lows in June 2007 causing <a href="http://www.sca.nsw.gov.au/water/dam-levels/weekly-verified-storage-reports">dam levels in Warragamba to increase by 14%</a>, undoing more than four years of storage declines. The wettest day on record for Sydney, on August 6, 1986, was also an East Coast Low, which caused an incredible 328 mm of rain over 24 hours. </p>
<p>The East Coast Low this week has caused widespread severe weather and damage. Impacts in the Hunter Valley, while severe, appear at this point similar in magnitude to the <a href="http://www.bom.gov.au/nsw/sevwx/facts/events/june-07-ecl/index.shtml">East Coast Low in June 2007</a>, which caused major flooding and nine deaths in the Hunter as well as causing a 76,000 tonne ship (the Pasha Bulker) to become beached at Nobbys Head. </p>
<p>There have been numerous other severe East Coast Lows in the historical record, with an East Coast Low in May 1974 also causing the shipwreck of the MV Sygna on Stockton beach, north of Newcastle. </p>
<p>At Sydney, the 24 hour total to 9 am on the 21st is the wettest individual day in more than 10 years. However, there have been more than 60 wetter days in Sydney since records began in 1858, including an incredible 328 mm during an East Coast Low on August 6, 1986. </p>
<p>This latest East Coast Low is a severe event, but not a record. In fact, Sydney experiences rainfall above 100 mm almost once a year on average, so this is a normal feature of our climate.</p>
<h2>And before you ask, is climate change to blame?</h2>
<p>The difficulty in deciding on exactly what separates an East Coast Low from other systems, the very large year to year variability in their frequency, as well as large inconsistencies in the East Coast Lows identified when we use different data sources and computer methods, make this a very difficult question to answer.</p>
<p>However, recent research is suggesting that the frequency of East Coast Lows, particularly the major winter systems that cause large waves, may <a href="https://theconversation.com/surfs-down-climate-change-likely-to-bring-fewer-big-waves-24126">actually decrease</a> over the coming century given current climate projections.</p>
<p><em>This article is based on a <a href="http://acaciapepler.weebly.com/blog/so-what-is-an-east-coast-low">blog post</a> written by Acacia Pepler.</em></p><img src="https://counter.theconversation.com/content/40564/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Acacia Pepler receives funding from the Australian Research Council.</span></em></p><p class="fine-print"><em><span>Lisa Alexander receives funding from the Australian Research Council.</span></em></p>What causes the wild weather that’s hit Sydney and central New South Wales over the past 24 hours?Acacia Pepler, PhD student, UNSW Climate Change Research Centre, UNSW SydneyLisa Alexander, Chief Investigator ARC Centre of Excellence for Climate System Science and Associate Professor Climate Change Research Centre, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/350032014-12-05T10:48:45Z2014-12-05T10:48:45ZCongress shouldn’t revive the failed policy of subsidizing wind farms<figure><img src="https://images.theconversation.com/files/66250/original/image-20141203-3622-18zwurt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Wind farms like this one probably wouldn't exist if the government didn't provide a hefty subsidy. </span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Congress passed the wind production tax credit (PTC) more than two decades ago to spur development in an industry still in its infancy. The wind sector has since matured into adulthood, prompting thousands of turbine farms to sprout in fields across the country. </p>
<p>The credit, worth 2.3 cents per kilowatt hour of wind electricity produced, expired at the end of 2013 but is being considered for renewal as part of a <a href="http://rules.house.gov/sites/republicans.rules.house.gov/files/113-2/PDF/113-HR5771-SxS.pdf">package of tax breaks</a> that passed the House on Wednesday and is expected to pass the Senate before Christmas. But before that happens, the PTC deserves a critical reevaluation. And the results don’t look good.</p>
<p>When they passed it in 1992, lawmakers had hoped the credit would create a robust domestic wind infrastructure and allow the renewable resource to chip away at fossil fuel’s mammoth share of US energy production. The hope was that the industry could eventually thrive without the subsidy. </p>
<p>The PTC provided incentives that contributed to the development of roughly <a href="http://www.csmonitor.com/Environment/Energy-Voices/2013/1206/Wind-energy-tax-credit-Is-it-worth-the-money">58,000 megawatts</a> of wind electricity. But recent evidence shows that those additional megawatts were merely a response to an overzealous subsidy environment, rather than real-world improvements in wind efficiency and cost reductions. </p>
<p>Since the PTC’s latest expiration last year, the growth in wind power has plummeted, from 13,128 megawatts of added capacity in 2012 to only <a href="http://www.awea.org/Resources/Content.aspx?ItemNumber=6865">1,255 megawatts</a> of additional electricity so far this year. Similar drops have occurred during the several previous lapses in the PTC, lending credence to the idea that wind’s rise has been born entirely from heavy subsidies. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/66339/original/image-20141204-7256-1icfo38.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/66339/original/image-20141204-7256-1icfo38.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/66339/original/image-20141204-7256-1icfo38.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=395&fit=crop&dpr=1 600w, https://images.theconversation.com/files/66339/original/image-20141204-7256-1icfo38.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=395&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/66339/original/image-20141204-7256-1icfo38.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=395&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/66339/original/image-20141204-7256-1icfo38.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=496&fit=crop&dpr=1 754w, https://images.theconversation.com/files/66339/original/image-20141204-7256-1icfo38.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=496&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/66339/original/image-20141204-7256-1icfo38.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=496&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Impact of PTC expiration.</span>
<span class="attribution"><span class="source">Union of Concerned Scientists</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>‘They don’t make sense’</h2>
<p>The <a href="http://dailycaller.com/2014/05/06/warren-buffett-i-build-wind-turbines-to-lower-my-corporate-taxes/">words of Warren Buffet</a>, whose Berkshire Hathaway <a href="http://online.wsj.com/articles/buffett-puts-wind-in-berkshires-sails-1414084146">has invested billions of dollars</a> in wind farms, speak for themselves: “[W]e get a tax credit if we build a lot of wind farms. That’s the only reason to build them. They don’t make sense without the tax credit.” </p>
<p>There’s a good reason the growth in wind capacity has fallen to pre-PTC levels: the cost to install a new wind farm has not dropped as significantly as lawmakers had hoped. They intended the credit to ignite a rapid push for innovation in the wind sector, driving down production and installation costs. </p>
<p>Instead, we’ve witnessed little change in wind installation prices, with costs in the late 2000s actually rising above those experienced a decade earlier. These numbers reflect how a significant subsidy has failed to make wind power a competitive market option. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/66340/original/image-20141204-7256-10mcnzz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/66340/original/image-20141204-7256-10mcnzz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/66340/original/image-20141204-7256-10mcnzz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=298&fit=crop&dpr=1 600w, https://images.theconversation.com/files/66340/original/image-20141204-7256-10mcnzz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=298&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/66340/original/image-20141204-7256-10mcnzz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=298&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/66340/original/image-20141204-7256-10mcnzz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=375&fit=crop&dpr=1 754w, https://images.theconversation.com/files/66340/original/image-20141204-7256-10mcnzz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=375&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/66340/original/image-20141204-7256-10mcnzz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=375&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Recreated chart.</span>
<span class="attribution"><span class="source">Lawrence Berkeley National Laboratory</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>What’s the harm?</h2>
<p>So what’s the harm in keeping the PTC if it has managed at a minimum to increase the total amount of electricity generated by wind power? Isn’t any progress away from fossil fuel consumption a good thing? Not necessarily. </p>
<p>The subsidy that has encouraged Warren Buffett and others to invest in wind turbines comes with significant opportunity cost. In other words, the tens of billions of dollars that have been diverted towards building new wind facilities over the past two decades could have been spent on more promising technologies such as<a href="http://www.oceanenergycouncil.com/ocean-energy/tidal-energy/">tidal power</a>, <a href="http://www.ethanolrfa.org/pages/advanced-ethanol">cellulosic ethanol</a> or even more efficient <a href="http://www.renewableenergyworld.com/rea/news/article/2013/06/energy-storage-moves-wind-to-baseload">battery storage systems</a>. </p>
<p>But why would an energy company bother investing in other technologies when it can collect a tax credit that equals <a href="http://www.csmonitor.com/Environment/Energy-Voices/2013/1206/Wind-energy-tax-credit-Is-it-worth-the-money">one-third</a> of the average cost of producing electricity to power homes and offices? Which then allows them to sell its power output at a <a href="http://instituteforenergyresearch.org/wp-content/uploads/2013/10/Giberson-study-Final.pdf">loss of $35 per megawatt hour</a> and still turn a profit? </p>
<p>The answer is they won’t, and the losers are many: taxpayers, other renewable energy developers and the environment. Keep in mind—the examples of potentially better uses of all those tax credits are not necessarily economically efficient solutions either (nor are they the only alternative options). But they are unlikely to be explored as long as power companies can game the wind subsidy system.</p>
<h2>A riskless bet</h2>
<p>The PTC turns a weak technology into a riskless bet, encouraging energy companies to spend their limited renewable budgets on subsidy farming rather than the best prospective solutions. The major players in the US wind industry will continue their <a href="http://www.ibtimes.com/us-wind-industry-races-revive-key-renewable-energy-tax-credit-congress-adjourns-1726422">efforts of subsidy-seeking</a> in the coming weeks as they try to convince lawmakers to revive the credit. That makes now a good time to reexamine the original intent of the PTC and to ask if it has made any progress in accomplishing its goals. </p>
<p>The policy has not fostered wind technology improvements. The PTC has only encouraged companies to install wind turbines rather than more promising energy sources. The credit was arguably a misguided policy back in 1992, but with two decades of paltry results, it is safe to say that the wind production tax credit can now officially be deemed a policy failure.</p>
<p><em>Arthur Wardle, a student research associate at Strata, contributed to this article.</em></p><img src="https://counter.theconversation.com/content/35003/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Randy Simmons received funding from the US Department of Energy (grant has been completed and there is no current funding) and Strata, a 501 (c)3 non-profit organization, of which he is president and director of research. He is also a senior fellow at the Property and Environment Research Center. From 2008 to 2013, he was the Charles G Koch professor of political economy at the Jon M Huntsman School of Business. </span></em></p>Congress passed the wind production tax credit (PTC) more than two decades ago to spur development in an industry still in its infancy. The wind sector has since matured into adulthood, prompting thousands…Randy Simmons, Professor of Political Economy, Utah State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/145192013-05-21T08:00:39Z2013-05-21T08:00:39ZExplainer: why are tornadoes so destructive?<figure><img src="https://images.theconversation.com/files/24186/original/mbsyz2jt-1369110814.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Tornadoes are common in the US Great Plains, but still devastating.</span> <span class="attribution"><span class="source">Carsten Peter/EPA/World Press Photo</span></span></figcaption></figure><p>Tornadoes are a part of life for people living in the Great Plains of the United States. In Oklahoma, a state that averages <a href="http://www.ncdc.noaa.gov/oa/climate/severeweather/tornadoes.html">62 tornadoes a year</a>, people are prepared as best as they can be and are well warned. </p>
<p>It’s imperative that they are when a large population centre - the metro-area of Oklahoma City that contains over 1 million people - is in one of the most dangerous places on earth for <a href="http://www.srh.noaa.gov/images/oun/spotter/sigtornadoes.jpg">significant and destructive tornadoes</a>. </p>
<p>Monday May 20 starkly highlighted this vulnerability when a violent and deadly tornado bore down on the sprawling suburb of Moore, south of Oklahoma City. Warnings came thick and fast and survival plans were enacted. At 3:14pm on that day, the US National Weather Service warned on its <a href="https://www.facebook.com/US.NationalWeatherService.Norman.gov?fref=ts">Facebook page</a>: “This is as bad it gets. Deadly dangerous tornado. Don’t know what else we can say. Take cover right now!” Nature is sometimes capable of laying waste to even the best-made plans.</p>
<p>Tornadoes are some of the most dangerous weather phenomena on earth. Their strength is measured by destructiveness using a system called the <a href="http://www.spc.noaa.gov/faq/tornado/ef-scale.html">Fujita (F) Scale, or the Enhanced (EF) Fujita Scale</a>, with numbers given from 0 to 5. </p>
<p>Weak tornadic winds (F0) will break branches and shift roof tiles. The strongest tornadoes have winds of up to 500km/h, dislodging asphalt from roads and uprooting concrete foundations (F5). </p>
<p>Wind speeds in an F5 tornado are much faster than their tropical cousins, hurricanes, although they affect a much smaller area. While hurricanes span hundreds of kilometres and last for days or weeks, tornadoes span only a few kilometres wide at most and usually last for less than an hour.</p>
<p>The mechanisms causing violent tornadoes are unique, making them relatively rare. However, on the Great Plains of the United States in the northern hemisphere spring, several factors come together to create the perfect conditions, giving the area the nickname “Tornado Alley”. </p>
<p>Fast-moving streams of air bring warm, moist air northward from the Gulf of Mexico. These provide the ingredients needed to generate tornadoes, which are usually spawned from a particular type of thunderstorm called a supercell. These thunderstorms have vigorous, rotating updrafts that are characterised by buoyant air rapidly moving upwards and spinning as it goes. </p>
<p>The winds rotate because the wind speed and direction changes with height, providing an abundance of something called vertical wind shear. It is this wind shear that causes supercells to rotate, and it is this strong rotating updraft, that spawns hail the size of cricket balls and devastating tornadoes.</p>
<p>Leaving a damage path more than 30km long, and lasting for more than 40 minutes, the tornado that hit Moore has been rated at least an F4, and may be upgraded to F5. </p>
<p>The tornado was a monster, but it was not unprecedented. The vulnerability to destructive tornadoes in this area of the world is high, and Monday’s tornado took a <a href="http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2412">similar track</a> to a similarly devastating tornado on May 3, 1999, which, at the time was described as the most destructive in history. </p>
<p>But no matter where in the world such a violent tornado hits such a highly populated area the consequences are <a href="http://www.theatlantic.com/infocus/2013/05/photos-of-tornado-damage-in-moore-oklahoma/100518/">devastating</a>.</p><img src="https://counter.theconversation.com/content/14519/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ailie Gallant is affiliated with Monash University and the Centre of Excellence for Climate Systems Science. She receives funding from the Australian Research Council.</span></em></p>Tornadoes are a part of life for people living in the Great Plains of the United States. In Oklahoma, a state that averages 62 tornadoes a year, people are prepared as best as they can be and are well…Ailie Gallant, Lecturer, School of Geography and Environmental Science, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/119092013-02-06T04:47:43Z2013-02-06T04:47:43ZTornadoes in Australia? They’re more common than you think<figure><img src="https://images.theconversation.com/files/19963/original/vnh6rd6n-1360040041.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Australian media might call them 'mini-tornadoes', but they're just as destructive as the real thing.</span> <span class="attribution"><span class="source">AAP Image/Paul Beutel</span></span></figcaption></figure><p>There is a long-standing myth that Australia doesn’t get tornadoes. This simply isn’t true. Just ask residents of <a href="http://www.abc.net.au/news/2013-01-26/tornado-rips-through-bargara/4485750">Burnett Heads and Bargara</a>, on Queensland’s southeast coast, or the Melburnians who were <a href="http://news.smh.com.au/breaking-news-national/thunderstorms-cause-havoc-in-melbourne-20111225-1p9ad.html">affected by tornadoes</a> on Christmas Day, 2011. </p>
<p>While we may not experience tornadoes with the same frequency or ferocity as in the United States – the most tornado-prone country in the world – they have been documented in Australia as <a href="http://trove.nla.gov.au/ndp/del/page/644581">far back as 1834</a>. The <a href="https://www.australiangeographic.com.au/blogs/on-this-day/2013/11/on-this-day-in-history-first-picture-of-a-tornado-in-australia/">first photograph</a> of an Australian tornado was taken back in 1911.</p>
<p>The strongest and most violent tornadoes spawn from large thunderstorms that are characterised by rotating updrafts, called supercells. These supercell thunderstorms form most frequently in the mid-latitude regions of the world (about 30-60 degrees north and south) during spring and summer, when the right “atmospheric ingredients” come together. </p>
<p>Three key atmospheric ingredients are an <a href="http://en.wikipedia.org/wiki/Atmospheric_instability">unstable atmosphere</a>, strong vertical wind shear (a change in wind speed and/or direction with height), and low-level moisture.</p>
<p>The tornadoes that struck Queensland’s southeast coast over the Australia Day long weekend were associated with Ex-Tropical Cyclone Oswald. These types of tornadoes have been well-documented in the United States. However they are probably under-reported in Australia due to our relatively low population density in the regions where tropical cyclones make landfall – particularly over Western Australia. </p>
<p>They require the same three basic atmospheric ingredients, although the relative amounts differ somewhat from tornadoes that form in the mid-latitudes, including in the famous “<a href="https://theconversation.com/tornado-alley-3d-an-authentic-storm-chasing-experience-3727">tornado alley</a>”. In what may be the first well-documented case in Australia, in February 2011 a tornado associated with Tropical Cyclone Carlos moved through the town of Karratha, Western Australia, leaving behind an extensive damage path.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/5jZEtSvs_Ag?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A tornado hits Bargara.</span></figcaption>
</figure>
<p>There is no doubt some confusion in the public’s mind as to what a tornado is exactly, and I think this is largely due to the Australian media’s mixed terminology. Do a quick google search on the most recent event in Queensland and you will find a number of different words to describe the same phenomenon, including “mini-cyclone” and the most-often used term “mini-tornado”. </p>
<p>According to the <a href="http://www.ametsoc.org/">American Meteorological Society</a>, a tornado is “a violently rotating column of air, in contact with the surface, pendant from a cumuliform cloud, and often (but not always) visible as a funnel cloud.” The definition makes no distinction on size; in fact, tornadoes with relatively small diameters have been observed to cause more damage than much larger tornadoes. The Australian media should simply adopt the word tornado and discontinue other commonly used terms that could be potentially misleading.</p>
<p>What about climate change and tornadoes? Unfortunately, our record of tornado reports is not complete enough to conclude anything about past trends, and current global climate models are unable to resolve small-scale features such as thunderstorms and tornadoes. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/19980/original/xzc572rz-1360101362.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/19980/original/xzc572rz-1360101362.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=440&fit=crop&dpr=1 600w, https://images.theconversation.com/files/19980/original/xzc572rz-1360101362.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=440&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/19980/original/xzc572rz-1360101362.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=440&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/19980/original/xzc572rz-1360101362.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=553&fit=crop&dpr=1 754w, https://images.theconversation.com/files/19980/original/xzc572rz-1360101362.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=553&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/19980/original/xzc572rz-1360101362.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=553&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Australia’s first-photographed tornado.</span>
<span class="attribution"><span class="source">Museum Victoria</span></span>
</figcaption>
</figure>
<p>Population growth should also be taken into account because, all else being equal, it will inflate the number of reported tornado events. According to the <a href="https://www.ipcc.ch/report/managing-the-risks-of-extreme-events-and-disasters-to-advance-climate-change-adaptation/">latest special report</a> by the IPCC, Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation: </p>
<blockquote>
<p>Thunderstorms, tornadoes, and related phenomena are not well observed in many parts of the world. Tornado occurrence since 1950 in the United States, for instance, displays an increasing trend that mainly reflects <a href="https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg1-chapter3-1.pdf">increased population density</a> and increased <a href="https://www.gfdl.noaa.gov/bibliography/related_files/kek0801.pdf">numbers of people</a> in remote areas . Such trends increase the likelihood that a tornado would be observed. A similar problem occurs with thunderstorms. Changes in reporting practices, increased population density, and even changes in the ambient noise level at an observing station all have led to inconsistencies in the observed record of thunderstorms. (p. 123). </p>
</blockquote>
<p>The best we can do at this point is to make predictions on how the atmospheric ingredients (such as wind shear) associated with tornadoes may change. However, trends in these ingredients have been shown to have <a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2008EO530001">opposite signs</a> in the future, leading to uncertainty in tornado trends.</p>
<p>While we may not know how small-scale extreme weather phenomena will change in a future climate, if we continue to improve our short-term prediction of such extremes this will no doubt help us to adapt to their longer-term trends.</p><img src="https://counter.theconversation.com/content/11909/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hamish Ramsay receives funding from the ARC Centre of Excellence for Climate System Science.</span></em></p>There is a long-standing myth that Australia doesn’t get tornadoes. This simply isn’t true. Just ask residents of Burnett Heads and Bargara, on Queensland’s southeast coast, or the Melburnians who were…Hamish Ramsay, Senior research scientist, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/104642012-11-02T02:01:32Z2012-11-02T02:01:32ZThere’s still no evidence that wind farms harm your health<figure><img src="https://images.theconversation.com/files/17172/original/b77ndd63-1351744355.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">It's easy to claim "wind turbine syndrome" exists, but where's the evidence?</span> <span class="attribution"><span class="source">Snurb</span></span></figcaption></figure><p>Back in July I wrote an <a href="https://theconversation.com/wind-turbine-syndrome-a-classic-communicated-disease-8318">article for the The Conversation</a> arguing that wind turbine syndrome was a classic “communicated” disease: it spreads by being talked about, and is therefore a strong candidate for being defined as a <a href="http://en.wikipedia.org/wiki/Psychogenic">psychogenic</a> condition.</p>
<p>Wind farm opponents repeatedly argue that turbines cause both rapid and long-gestation health problems. At the time the article was published I’d counted 155 health problems that had been attributed to wind farms including cancer, hemorrhoids, weight loss, weight gain and death. The list now stands at 198.</p>
<p>On Sunday, I received <a href="http://docs.wind-watch.org/Laurie-to-Chapman.pdf">an emailed letter</a> of response from Sarah Laurie, Australia’s most prominent proponent of the view that wind turbines cause health problems in people exposed to them. She circulated the letter widely and it ended up on the anti-wind farm action website, WindWatch.</p>
<p>Here is my point-by-point response to Laurie’s claims and questions. </p>
<hr>
<p><strong>Sarah Laurie <a href="http://docs.wind-watch.org/Laurie-to-Chapman.pdf">says</a> she has obtained information about the health effects of wind turbines from “sick residents”</strong>. </p>
<p><em>My response</em>: the “information” she is obtaining will be un-publishable in any serious research journal because she has no clearance from any institutional human ethics committee to obtain it. Laurie has a lengthy record in making public statements that are likely to cause considerable anxiety and distress about wind farms. Here is <a href="http://tobacco.health.usyd.edu.au/assets/pdfs/publications/SarahLaurieSpeechMortlake2012.pdf">an example</a>.</p>
<p>Against this background, any human ethics committee would be greatly concerned about her conducting “research” with such distressed people who are highly likely to know or be told of her views. Actively spreading alarm is likely to contribute to <a href="http://www.aerzteblatt.de/pdf.asp?id=127210">nocebo effects</a>, something she ought to be personally concerned about as a former practicing GP. </p>
<p>Any legitimate researcher doing what she claims to be doing would be dismissed from their research job for engaging in “research” on human subjects without ethics approval.</p>
<hr>
<p><strong>Laurie <a href="http://docs.wind-watch.org/Laurie-to-Chapman.pdf">points to</a> evidence from Daniel Shepherd and colleagues to show wind turbines are harmful to human health.</strong> </p>
<p><em>My response</em>: Shepherd et al’s <a href="http://www.ncbi.nlm.nih.gov/pubmed/21959113">paper</a> reported lower sleep quality and a “less restful environment” in a turbine-exposed community in the Makara Valley in New Zealand, than in a matched nearby community without turbines. </p>
<p>Fiona Crichton from the University of Auckland provides the following <a href="http://tobacco.health.usyd.edu.au/assets/pdfs/publications/ShepherdReview.pdf">critique of the paper</a>:</p>
<blockquote>
<p>The study was cross-sectional and used a non-equivalent comparison group. The wind farm sample was drawn from 56 houses and the control group from 250 houses. The researchers do not identify how many participants per household were recruited, however the final sample included 39 people in the wind farm group and 158 in the control group. While there were differences detected between the groups in relation to satisfaction with the living environment, critically there were no differences between the groups in terms of self-rated health and current illness. </p>
</blockquote>
<p>You can read more of Fiona Crichton’s critique <a href="http://tobacco.health.usyd.edu.au/assets/pdfs/publications/ShepherdReview.pdf">here</a>.</p>
<hr>
<p><strong>Laurie <a href="http://docs.wind-watch.org/Laurie-to-Chapman.pdf">says</a> the Shepherd et al paper provides “incontrovertible” evidence that wind farms cause sleep problems.</strong> </p>
<p><em>My response</em>: Experienced researchers rarely if ever use expressions such as “incontrovertible” unless there is a massive amount of high quality evidence (which here, there is not). </p>
<p>Fiona Crichton’s critique actually does not go far enough. The paper says nothing about the activities of the <a href="http://en.wikipedia.org/wiki/Makara_Guardians">Makara Guardians</a>, an anti-wind farm group active in the area since 1997. It is inconceivable that anyone living in that small-populated area could have not been exposed to the anti-wind farm information spread by that group, including alarm about alleged health problems. Such activity is an obvious trigger for nocebo effects. The omission of any mention of this important factor in the paper is a disgrace.</p>
<hr>
<p><strong>Laurie <a href="http://docs.wind-watch.org/Laurie-to-Chapman.pdf">asks</a>, “Are you prepared to explain why you do not reference the peer reviewed published work of Daniel Shepherd and his colleagues…?”</strong></p>
<p><em>My response</em>: It is a very poor paper. </p>
<p>But we should all ask why she persistently ignores the conclusions of <a href="http://tobacco.health.usyd.edu.au/assets/pdfs/WindHealthReviews.docx">17 reviews</a> of the evidence that all reject her views about wind turbines causing health problems, except when she is in denial of what they all conclude. Why does she never tell her enthralled audiences about what these reviews <a href="http://tobacco.health.usyd.edu.au/assets/pdfs/publications/WindHealthReviews.pdf">have concluded</a>? </p>
<hr>
<p><strong>Laurie <a href="http://docs.wind-watch.org/Laurie-to-Chapman.pdf">selectively quotes</a> the acoustician Geoff Leventhall, including claiming he “has known about the symptoms of low frequency noise exposure or ‘wind turbine syndrome’ for some time”.</strong> </p>
<p><em>My response</em>: Laurie knows that Leventhall very much disagrees with her about the health impacts of wind farms. For example, Leventhall wrote:</p>
<blockquote>
<p>“I am appalled that Laurie asserts that experimental exposure to high levels of infrasound, around 125dB or higher, is relevant to the low levels of infrasound from wind turbines, although this gross misunderstanding might explain some of her irrelevant and inaccurate statements.”</p>
</blockquote>
<p>Why does Laurie persist in quoting an acoustical authority as if they support her when Leventhall has repeatedly clarified his strong rejection of her views?</p>
<hr>
<p><strong>Laurie <a href="http://docs.wind-watch.org/Laurie-to-Chapman.pdf">claims</a> people affected by wind turbines have been gagged from speaking out about their health problems. She quotes Slater & Gordon’s General Manager as evidence of these gags.</strong> </p>
<p><em>My response</em>: The debate here is about alleged gags: the idea that people who claim to have been made ill cannot speak out because they have signed contracts cancelling their rights under common law to sue for negligence. </p>
<p>The “evidence” Laurie refers to are dispute <em>settlements</em>, not complaints prior to those settlements. It is common for legal settlements about all sorts of issues, not just wind turbines, to contain confidentiality clauses. </p>
<p>The only confidentiality or “gag” clauses refer to financial transactions — standard commercial practice across all sectors. This is understandable, as the companies want to be able to negotiate with hosts on a commercial-in-confidence basis. </p>
<p>While some contracts do appear to have gag clauses, these are likely to be unenforceable in any case where true negligence or harm could be established.</p>
<hr>
<p><strong>Laurie <a href="http://docs.wind-watch.org/Laurie-to-Chapman.pdf">insinuates</a> that because I am “a sociologist” and not a medical “practitioner” or an acoustician that my views should be dismissed.</strong> </p>
<p><em>My response</em>: It might have escaped Laurie’s attention that there are many people whose claims she quotes authoritatively who also do not have undergraduate degrees in medicine or acoustics. </p>
<p>Nearly all the authors of the collection of anti-wind farm essays in the Bulletin of Science and Technology do not have undergraduate degrees in medicine. Nor does her chairman Peter Mitchell, who studied engineering at university many decades ago. Nor does Daniel Shepherd. I could go on.</p>
<p>Why does Laurie think people should take her seriously as she parades herself as an arbiter of “incontrovertible” research when she:</p>
<ul>
<li>has no qualifications at all in any research discipline,</li>
<li>has repeatedly demonstrated (as in her assessment of Shepherd et al’s paper and Leventhall’s comments on her understanding of infrasound) that she has poor understanding of research, </li>
<li>has never published a single piece of research on any subject, and </li>
<li>for some time used the research degree post-nominal “MD” on the Waubra Foundation’s Australian website (see below) when she does not have a doctoral degree in medicine, but only bachelors qualifications?</li>
</ul>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/17179/original/ggx3sh5n-1351745905.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/17179/original/ggx3sh5n-1351745905.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/17179/original/ggx3sh5n-1351745905.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/17179/original/ggx3sh5n-1351745905.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/17179/original/ggx3sh5n-1351745905.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/17179/original/ggx3sh5n-1351745905.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/17179/original/ggx3sh5n-1351745905.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/17179/original/ggx3sh5n-1351745905.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Screenshot of Waubra Foundation’s Australian website (13 Oct 2011) before it was changed.</span>
</figcaption>
</figure>
<h2>Now, some questions for Sarah Laurie:</h2>
<ol>
<li><p>Will you provide a list of the addresses of all the “many” houses adjacent to wind farms in Australia that you claim people have “walked away from” so that these can be verified (after submitting a proposal to my university’s human ethics committee)? This verification will be sought via neighbours and local real estate agents. (One example often highlighted in Waubra involves the departure of a resident allegedly because of wind turbines when that person was in fact admitted to a long-stay facility for a degenerative condition unrelated to wind turbines.)</p></li>
<li><p>Why have there been zero health complaints associated with the large majority of Australian wind farms? Or do “susceptible” people somehow mysteriously only live near a few of them?</p></li>
<li><p>If wind turbines cause acute health effects within minutes of exposure, why then has it often taken several years for complaints to be expressed and why have these generally occurred after exposure to anti-wind farm propaganda?</p></li>
<li><p>Having appropriated the name of the town of Waubra for your foundation why do you not appear at any of the town’s celebratory events, such as the one held last month? Do you appreciate that there is widespread anger in Waubra about the way your foundation has used the name of the town?</p></li>
<li><p>Why is it that two acousticians you rely upon, Steven Cooper and Bob Thorne, are both refusing to release documents for open peer review that have been used to cast doubt upon compliance of wind farms with noise levels?</p></li>
<li><p>Why is it that after almost 2.5 years, you have not been able to recruit a single qualified and reputable Australian health or medical identity to publicly support your position?</p></li>
<li><p>Why do you persist in publicly describing yourself as a “clinician” when you have not practiced medicine for over 10 years?</p></li>
<li><p>Why is it that your organisation’s objectives (enshrined in your constitution) state that you will at all times maintain complete independence from wind farm advocacy groups when your directors are almost all associated with aggressive anti-wind activism? Why does your name appear as a contact on the anti-wind farm site <a href="http://www.swindleaustralia.com/contact-us.html">sWINDle</a> when you purport to not be anti-wind farms but only concerned about health issues? </p></li>
<li><p>Why does your organisation deserve the indirect government subsidy of DGR (deductible gift recipient) status to pay for its anti-wind activism, including the legal fees of people objecting to wind farm developments?</p></li>
<li><p>Why did your Chairman, Peter Mitchell, not explicitly disclose his involvement with fossil fuels and uranium in his <a href="http://www.nhmrc.gov.au/your-health/wind-farms-and-human-health/wind-farms-and-human-health-reference-group">statement of interests</a> with the NHMRC?
And why does his declaration say that he had involvement with the Australian Landscape Guardians until “mid-2010” when he authored a submission to the Australian Senate for them in February 2011?</p></li>
<li><p>With activism about fire risk and property values, an anti-wind farm board, no membership and no serious scientific agenda, how should the public see you as anything other than another anti-wind lobby group?</p></li>
</ol>
<p>Your actions are likely to be causing residents near turbines who may have legitimate noise concerns to be confused by outlandish claims of health effects that have near zero credibility. The unfortunate result will most likely delay the rectification of legitimate concerns.</p><img src="https://counter.theconversation.com/content/10464/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Simon Chapman does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Back in July I wrote an article for the The Conversation arguing that wind turbine syndrome was a classic “communicated” disease: it spreads by being talked about, and is therefore a strong candidate for…Simon Chapman, Professor of Public Health, University of SydneyLicensed as Creative Commons – attribution, no derivatives.