Gasification probably better than digestion (more energy out, smaller footprint etc)

Greg

How would you propose to solve THAT one!!!

At the very least require family planning driven fertility reduction as a compulsory component of foreign aid. No cooperation on fertility redeuction, then no foreign aid.

Reductions in the death rate should be offset by a reduction in the birth rate.

If absolutely necessary use coerscive measures on individuals to reduce their fertility, e.g. compulsory sub-dermal contraceptive in order to receive a food package.

In Australia abolish all measures that encourage greater than replacement fertility, e.g. the baby bonus and all government welfare payments for the third and greater child.

We better make all efforts to figure out how to do this as rapidly, humanely and fairly as possible Bruce because the alternative that David is alluding to is unthinkable

Sounds great in theory Tim, but how would you acheive that in Pakistan where the male muslims don't want their females to exhibit intelligent independant thought.

Coerscion may be necessary in countries like this.

That sort of strategy is going rather well in Afghanistan Tim........NOT.

Better to coerce the desired behaviour from their society when they want something from you, e.g. food, rather than try to impose it on them from a position of relative weakness.

Thanks for those references - I'll check them out. Prima facie your concerns seem reasonable - but that means renewables alone can't do the job - unless and until someone can point to a credible scenario that doesn't involve spinning gas reserve.

How could it be zero? unless at every point in production the energy used to create it was sourced from renewables, which it isn't nor highly unlikely to be, bio-fuel is the Claytons renewable.
http://www.ibtimes.co.uk/articles/20110322/biofuel-emissions-six-times-higher-than-fossil-fuels.htm

That link seems not to work, Ludwig, sort as "no baseload needed" doesn't work.

So cold fusion is not here right now, so we should just write it off and not even think about the research being done or think about doing any further research? From my reading of scientific literature, cold fusion is theoretically possible. There are some hurdles in the way that still need to be cleared but this 'never going to happen' attitude is a big one. One has to wonder whatever happened to scientific curiosity?

David, you chose to cite the efficiency of the hydrogen fuel cycle. I was merely pointing out that the solar cycle is equally inefficient. In fact the efficiency of most energy production systems is rather low - a direct consequence of the laws of thermodynamics. It is a price we have to pay - we live in an environment where thermodynamics places limits on what we can achieve. Ultimately arguments about efficiency are really arguments about relative costs.

I have to admit to some puzzlement about the antagonism to biofuels that have been exhibited on this thread. Ultimately all our organic fuels are biofuels - that is how they were produced. But at some point, if we still wish to fly, or drive around cars, we will need technologies that replicate nature but more rapidly. I personally believe that is possible.

Thanks Daniel and Mark expanding on my question.

The issue is converting the huge amount of solar into useable energy. The biofuel route of using good agricultural land to create fuel feedstock that converts less than 10% of the sunlight energy is marginal. On the other hand, Mark's 'front of the envelope' calculations indicating we would need to cover 220 million hectares of Australia's 770 million hectares, show the potential problems with massive solar plants.

One practical problem with very large PV sites is that the ground below becomes a shaded desert. One can imagine the planning issues that will entangle the site selection, especially when the proposed desertification threatens the lesser known, long necked numbat habitat.

Thanks

Gerard Dean

As usual, Mr Boxhall you challenge an profer an implied opinion out of ignorance.

The evidecne that biofuel production is already displacing food production and hence driving up prices, is abundant for anyone who actually looks at the evidence 9something I am aware you have apropensity to avoid if it might challenge your prejudices)

The evidence is also clear that there is a significant risk in the future posed by biofuels

http://www.choicesmagazine.org/magazine/pdf/article_41.pdf

"The analysis shows that enhanced demand
for biofuel crops has a strong
impact on agriculture at the global
and European level. Biofuel policies
contribute to the current rise in
world food prices, especially for those
products which are in direct competition
in final consumption for food
and fuel, e.g. corn, sugar and oilseeds.
With increased biofuel consumption,
the long term trend of declining real
world prices of agricultural products
slows down or might even be reversed
for the feedstocks used for biofuels.
This positive effect on world agricultural
prices has consequences especially
for poor urban populations in
low–income countries with food and
energy deficits. Those consumers will
suffer most in any sudden or rapid
price shift for basic commodities, of
which foremost is food."

More here

http://www.guardian.co.uk/environment/2010/aug/30/biofuels-land-grab-friends-of-the-earth

http://en.wikipedia.org/wiki/Indirect_land_use_change_impacts_of_biofuels

http://www.ecpa.eu/faq/increased-use-agricultural-land-biofuel-production-driving-food-prices-can-pesticides-help

"Demand for renewable energy, some of which can be met from crops, is reducing the amount of land available for food production and having a price impact"

Fine David - it's not "necessary" but today is happening - in significant quantities. In the quotes that I provided. try reading them and making, for once, an informed comment.

The exception is indeed the sort of algae based bio fuels that Peter Sommerville referred to

http://www.ecosmagazine.com/?paper=EC10041

They are also, however, subject to the efficiency limits that Alex has pointed out. For them to be useful and economic the total $ and emissions cost of growth, separation, harvesting, refinement and combustion must be neutral. That's not an easy task. Although their carbon capture properties and ability to use "waste" heat and being sited near power stations - to which Peter referred - provides some interesting opportunities perhaps

Finally! Getting the truth out of you is like extracting teeth.

You're such an 'expert', David!

Luddy, indeed to actually be 'green' means studying reality. And the reality is that biofuels are wasteful, by any engineering or scientific measures.

Solar on existing structure is excellent. Evs are excellent, for reasons you may not know. Storage is doing well and will be excellent. So, we only then need high power density 24/7 sources, like advanced nuclear.

Just because you don't get the science doesn't mean others are "trolls" (whatever that wimpy epithet is supposed to mean).

"How did we get from there to the nuclear lobbying?" -- Ludwig, the discussion is about what to do now that we've screwed up our descendents future by burning so much stuff.

Solar on local structures is good because: a) no land is wasted; b) efficiency is now above 20%; c) cost is <$1/W; and grid loss & stability are improved. Given the amount of human structure, it's more than possible to meet all peak daytime loadd with rooftop PV.

EVs are excellent as both forms of storage and energy capture via braking regeneration.

The remaining need is 24/7 baseload in all weather & with low environmental impact (high power density) -- that's nuclear. The link you gave misses the key benefits of nuclear power, one of which is safety. Yes, even the Swiss confirmed civilain nuclear power as the safest way to generate mass power ever deployed: http://tinyurl.com/42wvr9l

Note that even including Chernobyl, which is irrelevant to western nuclear power, nuclear generation remains the safest.

Perhaps you're unaware also of the NORM exemptions given to combustion power. They allow emissions of Radon, Polonium, Radium, etc., as well as nice atoms of Mercury, Arsenic... In other words, nukes are allowed to emit about 100x less radiation than are coal plants.

The greens have been exploited for decades by combustion folks supporting scares about nukes, because they know nuclear is the only system that can wipe combustion out -- exactly as JFK knew and planned to do by 2000: http://tinyurl.com/6xgpkfa

"Whenever the subject comes up, the lobbyists will swarm" -- indeed, Boxall, sort of as some Nobel winners and a President "swarmed"?

http://tinyurl.com/6xgpkfa

You need to get off desperate argumentation, David.

James, as soon as "fuel" follows "bio", we're talking >50% energy loss in combustion. As soon as crops are the bio, we're talking the photosynthesis cycles, as this article describes -- < 10% efficient. So, any biofuel system nets at absolute best, 5% of solar input.

Solar PV nets 20% and growing, with no land consumption. The resources are the same as in any electronics industry and very little per Watt. That;'s why PV is now <$`/W. It's also to the fabricator's advantage to minimize materials, so the silicon wafers now used for cells are extremely thin, making the overall structura little demanding of support materials, like aluminum. On top of that, conversion devices are now inexpensive. So local solar PV is a great investment for all.

The idea that a silicon crystal doped in ppm with any element is toxic is as silly as saying eating beach sand will kill a kid.

And, there is such broad physics involved with future solar PV designs that no one can say how efficient, cheap & safe they'll be.

As to storage, there are equally many physical opportunities, including the nano-material systems such as ultra-capacitors -- fully benign, light and durable. Efficient storage is indeed in the cards, partly because it needed for efficient EVs.

Biofuel, for mass use, is a dead end, per chemistry, physics & Ma Nature.

When ll the resources are added up and the woeful efficiency tallied, biofuels are exposed as a sham.

Mother Nature didn't devise photosynthesis to make us vehicle power.

The Calif. "million solar homes" initiative is a start, as are the new waste-handling initiatives, which include digestion of community organic wastes and use of the methane for power.

Playing the record again: there's >2% of earth's surface covered with human structure, which at 20% efficiency, can produce more PV power than the world uses on a peak day.

Hi Alex, help me out. I'm struggling to reproduce your Solar PV figures - or, more properly, my calculations are showing less than 0.02% of the earths surface is theoretically needed to do the job (ignoring night times and lousy days) - which stunned me so I wonder what I am missing?

I've looked at both "peak" power and annual energy consumption

1) Projected power generation requirements by the IEA in 2035 are around 20TW. For peak insolation of 1kW/m-2 and a 20% efficiency 1m2 of solar PV will produce 200W. The surface area of the earth is around 510 million km2. To produce 20TW at peak requires 1 x10^11 m2 - or less than 0.02% of the total

2) Projected annual energy consumption is of the order of 150,000 TWh (that 20TW is not generating all the time). Assuming a midday peak solar insolation of 1Kw/m-2, a useful time per day of 7 hours, a simple triangular solar distribtion function throughout the day (rather than a more realistic gausian) gives about 3.5kWhm-2 for PV per day or around 1.28MWh per year per m2. Not surpisingly one gets a similar result - around 1.2 x 10^11m2 required or just a little over 0.02%

This is 100 times less than overall built area you quote. Even allowing for much worse peak insolation figures due to angles etc which I can't see being that big a factor am I missing something or have I made an error?

I'm also struggling to reconcile that figure with this reference (from Dan's article) that indicates around 7500 hectares to supply an average (San Jose) 740MW power needs. On my figures of 1.28MWh m-2 in a year you need only a little over 500 hectares. Even if San Jose has peak insolation of < half it still doesn't add up

http://www.geneseo.edu/~bearden/socl217/EnergySciene.pdf

On the other hand

1) There are many days in many parts of the world were peak insolation will be WELL under 1kW/m-2 - so without either lots of storage or another source (gads- nuclear?) peak demand will not be able to met in those locales at those times. In saying this I'm assuming that below a certain level of insolation you get nothing out as there must be a minimum useful onsolation threshold (can't find figures on this so donlt know how much abive zero it is) - but perhaps it is possible to build sufficient capacity to overcome this?

2) I understand that recommended average minimum annual insolation is about 800kWh in a year - which can rule out around 30% of rooftop dwellings due to shading, angles etc but only excludes very high latitude lousy weather locales (all of UK, including the far north scottish isles are above this threshold - http://www.bristol.gov.uk/sites/default/files/documents/environment/climate_change/5%20Bristol%20Sunshine%20-%20An%20Analysis%20of%20Rooftop%20Solar%20Mapping.pdf ) - but again this suggests only a sighting problem.

I'm sorry if this is a bit detailed - and appreciate you may not have the time - but can you quickly see what I may have missed?

Regardless it certainly suggests Solar PV's only weakness is the ability to provide peak demand at night and on lousy weather days?

PS - if you don;t have this link you might enjoy it?

http://www.sma.de/en/company/pv-electricity-produced-in-germany.html

Hi Mark, your figuring is good, but the human structure area is >2% ,of land not .02% -- big difference! Since land is <1/3 earth's surface and the sun delivers 86,000,000,000MW to the surface, we get 24 years of our current 17TW generation every day. That's about 8 years worth each day to land. So >2% of that is what structure-based PV could provide, peak. It's about 50 days per day.

For 20% cells, we get down to >10days per day, if we can distribute the power around to the poor-sun regions. That''s what one idea in Europe is -- cable to N. Africa & cover the desert with panels. Think we had dependence on mideast energy before!?

The peak US demand could be met by an efficient PV array 200km on a side, in the desert. We don'[t need to waste that land -- just follow through on the "million solar homes" initiative in Calif., etc.

Now, the long-term issue is that we waste almost all of what we generate as heat. The 86,000TW coming in from the sun cannot have much added to by us, or just waste heat will be a problem, beyond GHGs. This reality, plus population maximum reality shape our future decisions.

One fellow likes to quote Iroquois elders when they sat to discuss tribal issues: "Let what we decide here today be done for the benefit of 7 generations hence" (or words to that effect).

That's what Ma Nature is holding in front of our faces, and Ma Nature doesn't care how dumb we are.
;]

Thanks Alex - maybe I didn;t explain myself well. My figuring shows that solar PV could provide for peak demand using ONLY 0.02% of total surface area - that jumps to 0.06% of land - still way under the 2% you claim is available for "built" land (a figure I don't dispute).

Even allowing for lower efficiencies, lousy days, poor sunlight areas etc it suggests Solar PV - if we can tie it to developments in storage technology - could meet all residential and commerical needs - perhaps only large indsutrial requiring something like nuclear.

I still think synthetic hydrocarbons will be needed for some transport applications though - as I;ve noted in a separate post

You're right Bill, it's an "and" question, with only a few sources that make the grade -- local solar and EVs and nuclear being three.

The belief that "biofuels" somehow aere green, hovere, just misunderstands the reality of their inherent inefficiency.

The fuels we need as liquids for aircraft, etc. can easily be produced via any heat source of 700C or so. That's possible with hi temp combustion plants now, though we don't want their emissions, and it's possible with advanced hi-temp reactors, such as the molten-salt systems.

The bottom line for any combustion system is thermodynamic reality -- efficiency is limited by the Carnot Cycle and two temperatures: combustion & exhaust. So efficiency in burning anything to get mechanical/electrical power is limited by (1 - Tcold / Thot), which is about 0.3 for diesel/gasoline engines.

Burning any fuel from any source immediately drops the available energy by a large fraction, and if that fuel came from a low-efficiency source, as all biofuels do, then the situation is very wasteful. Plus, the waste heat at each stage adds directly to global warming, even if there are no GHG emissions.

Really the problem the world faces in any issue, is mismanagement, it is rife in any field of human endeavour, we rarely if ever get it right, i.e. subsidised bio-fuels in the US starving people in Mexico, but did that stop them NO! even when they have been proved to have no environmental benefit whatsoever, it just made agricorps richer and thats all that counts really.
This whole debate renewables/fossil fuel debate is not about saving the planet, its about saving market share for corporations.
To burn fossil fuel and mine minerals at present rates, 500 maximum and they will all be gone, that is disgusting mismanagement.
In England they built a church 500 years ago, and planted an oak tree beside it, so that when the roof needed replacing they would have the timber, now that is forward planning, nowadays anything like that is unthinkable.

Balir - I did not claim no one has died as a result of Chernobyl - so you have misunderstood me. I have claimed no one has died as a result of Fukushima.

At least 50 people died driectly as a result of Chernobyl - and WHO estimates 4000+ following. A terrible outcome. Fukushima is different. But still - you haven't really dealt with the argument. You cannot extrapolate based on those situations - anymore than you can extrapolate all cars based on the Ford Pinto. And shutdowns/issues reported in the US ou vaguely refer to have NOT resulted in any accidents.

I though you would look at the evidence - which for nuclear shows a relative safety record per MWh produced better than almost every other alternative. You cannot reject nuclear because it is far from perfect but ignore the downsides of the alternatives.

The reality is, today, there is not a credible plan to displace the required amount of fossil fuel emission with renewables in anything like the time frame we need.

I'm glad we agree on the need for as much renewables as possible - but you obfuscate. I have not suggested it is impossible. That's not the point.

My ethical point, which you have sidestepped, is this

If we cannot achieve sufficient reductions in fossil fuel use through renewables alone - which is certainly a real possibility (I think a probability but I accept different views on this) then on what evidentiary basis is it ethical to reject nuclear in favour of additional warming? Remember the evidence shows the damage caused by nuclear, overall, is low and uncertain - but the damage caused by excessive warming is high and probable

You sound like one of Blair's Republicans, David. The link you gave doesn't work, and if you thought a bit you'd realize why I gave a hash of the true link. But here's what you say in your desperation isn't Swiss...
http://manhaz.cyf.gov.pl/manhaz/szkola/materials/S3/psi_materials/ENSAD98.pdf

Keep on spamming, David. It's your only hope (for what we can't guess).

Blair - thank you for this reasonable and respectful reply (and I hope you enjoyed the footy - my team, Geelong, has been bundled out so I;ve lost a little interest).

Your paragraph "I reluctantly accept that it's unlikely we'll replace the existing fossil fuel sources with renewables (as opposed to nuclear alternatives) in the time frame we need which is why I have also said I accept we will likely need nuclear for some time yet (in those countries that are prepared to live with it). Ultimately though, I cannot see why renewable energy won't provide the vast majority of our energy needs regarding electricity. (Energy for transport is another matter entirely)" suggests our views are not that far apart.

In regard to nuclear safety - there are some good figures here

http://www.scientificamerican.com/article.cfm?id=the-human-cost-of-energy

It shows quite clearly the overall human cost (though it doesn't include the health burden of fossil fuels - which produce more harmful, and radioactive - emissions per unit of power produced than nuclear does - by a large factor). To be fair it does NOT include Chernobyl - but even if you do include (for example) the WHO reported deaths it doesn't change the data by much.

I agree we need to LEARN from the past but NOT to extrapoloate from it when the basis of that extrapolation is flawed - if we did that we'd ban all car and air travel - clearly we do not - we learn and fix the problems. That's what's been happening with nuclear.

As for you comment about a nuclear worst case accident being "worse" than a single Wind Turbine accident? With due respect that's a failure of what's known as the Availability Heuristic http://en.wikipedia.org/wiki/Availability_heuristic

Becuase Nuclear accidents are so much more "visible" people assume they are more likely.

It's similar to the flawed logic that concludes air travel is less safe than car travel - many people have a greater fear of air travel because air travel accidents, when they do happen, are so much more "visible" in our minds - but I'm sure you are aware on a passenger travelled per km basis (or any other valid measure) car travel is 50 to 100x more dangerous.

In saying that I'm not suggesting Wind is MORE dangerous than Nuclear - although as Alex has pointed out in the USA 2 people have been killed in Wind Turbine accidents, none in nuclear - I AM saying that your comparison is flawed.

In relation to nuclear being "renewable" I suggest you do more research - there are more than enough supplies of nuclear fuel to power a modern reactor fleet for many thousands of years - effectively inexhaustible - so I again I suggest your reasning is based on flawed evidence.

My key challenge is this - which I think I may have already put to you but not had a response -

"if renewables cannot do ALL of job we need to avoid dangerous AGW (and the evidence suggests they need to play a significant part but can't do all of it and I think you have reluctantly conceeded this) - and reductions in power consumption globally are chimeras (as the IEA points out) - what degree of additional AGW is ethical to accept in order to avoid the perceived risks of nuclear?"

Mark, at least your team can play, my mob (Melbourne) seem to have lost the will to live… *Sigh*

Thanks for the link regarding safety, I will have a look at it.

"Becuase Nuclear accidents are so much more "visible" people assume they are more likely."

No, I don't assume they are more likely but experience does suggest that when something does go wrong, the results are far more detrimental. That is my only point.

Alex may well be right regarding deaths in relation to nuclear versus wind in the US but anybody can cherry pick data to suit a particular point of view. As best I can tell, AGW is a global phenomenon that all countries have to deal with and when we look at all (known) nuclear accidents the safety record of nuclear does not paint it in a good light in comparison to any renewables.

I enjoy science podcasts and I wonder if you have heard of a series called "Little Atoms"? A BBC series I believe. Don't let the name deceive you, it's not strictly about nuclear power. Recently the host went on a road trip through the US interviewing a variety of scientists and others (including one geologist who also happens to be a creationist - talk about cognitive dissonance) but I would like to mention the 20th episode to you.

Little Atoms Road Trip 20 – Los Alamos National Laboratory
http://www.littleatoms.com/roadtrip.htm

The show's host, Neil Denny, interviews an energy expert by the name of Richard Martin who is a strong proponent of thorium as a source of nuclear power. It's a very interesting programme that explains why we are stuck with uranium (for the foreseeable future) rather than thorium and the various costly problems that are intrinsically linked with uranium. He also explains quite clearly why thorium is or would be a far better option and that it has been demonstrated to work very well without the need for pressure containers and the other numerous problems linked to uranium usage.

I have read that the Chinese are experimenting with uranium fuel in pebble bed reactors which are supposedly much safer than existing nuclear plant designs. They sound like a promising alternative but information is hard to come by.

Regarding your last question, you are setting up a false dichotomy and misconstruing my position. I have stated earlier on numerous occasions that I acknowledge we may need to rely on nuclear for some time to come to help combat AGW, but, I sincerely hope we can find a way to avoid that route if it's practical and possible. AGW must be the primary concern over and above the local dangers of a nuclear power plant crapping out. Has that answered your question?

Alan John Hunter,

"we could cut consumption by at least 75%, without nuclear and its inherent dangers, then renewables are clearly a viable option.

Its pointless even thinking of alternatives without addressing efficiency and waste."

The world is not going to cut consumption. Population is growing and we it wants higher standard of living. Energy consumption will continue to increase. That's the reality. Energy efficiency improvements, faster than we are already making, can make only a small difference to the rate of growth of emissions, and certainly cannot make the growth negative.

What is needed is to decarbonise the global economy at a much faster rate. In the 1990's we were decarbonising at the rate of about 2% pa. Now we are decarbonising at the rate of 0.7% pa http://rogerpielkejr.blogspot.com.au/2010/07/decelerating-decarbonization-of-global.html . The reason for the slowing is partly most hydro has been developed and there is little more available and partly that the rapid rate of roll out of nuclear power in the developed economies - that took place from 1960 to about 1990 - has stopped (thanks to the 'Progressives' blocking progress).

If you want the world to decarbonise, energy efficiency and renewable are fringe players. We need a cost competitive alternative to fossil fuels.

It's that simple and obvious.

Mark, don't worry I've been keeping an eye on the issue of tipping points. The decreasing ice cover at peak summer in the Arctic is a great concern - not that you'd know it listing to the various right-wing echo chambers and their apologists in these forums and elsewhere - as bad as the ice melt is, another great concern is the thawing of the permafrost regions just south of the Arctic ice sheet. Canada, Alaska and Siberia in particular.

NASA and ESA have over the last few years launched a number of satellites dedicated to monitoring loss of ice cover, changes in atmospheric chemistry and sealevel rise. I suspect the news in the next couple of years will only provide comfort to those who believe in Armageddon. Meanwhile we need to force the crackpot religious right to reconnect with reason, fact and evidence rather than hide behind political expediency and dogma.

Blair, you may be aware, many if not most are not.

I mention Arctic Sea Ice because it is happening now - once it's gone at the summer peak, possibly within just a few years, the associated drop in albedo and increased warming absorption due to greater sea cover paves the way for the next big two - permafrost melting and the concomittant relase of vast amounts of methane and accelerated melting of Greenland ice.

If these things happen it will make IPCC "alarmist" projections look like head in the sand ignorance and pretence there is not a problem.

Trouble is, once they are observable it is too late to do anything about them. It is possible, though I hope not likely, that they are already "locked in". Hence why I suggest urgent action may bee required - including nuclear.

If we do not rapidly decrease our fossil fuel dependent emissions, instead of increasing them as we are, we are far worse "toast" than any French variety the likes of Mr Boxall or other so-called greens can imagine.

It won't be an Armageddon - the planet will be fine. Human civilisation, however, will experience it's biggest fall since thedecline and fall of Rome, if not since it rose in the first place.

Mark, the definition I have of Armageddon is the end of the human race. The Earth can certainly survive happily enough without mankind messing about on its surface.

A rapid reduction in the use of fossil fuels has to be a given and I think it's time people stopped arguing about the merits of alternative sources and employed the practical options where best suited. The finessing and fine tuning can be done at a later stage when (or if) the damage we are doing is minimised.

Unlike nuclear power, wind, solar and solar thermal can be deployed in large numbers comparatively quickly. And, they have the benefit of being distributed and reducing the risk of a single accident or natural disaster knocking out a large chunk of generation capacity.

We are a long way from the subject matter of the original article (which I think promoted a false dichotomy in the first place).

I'd like to see a couple of wind turbines constructed on the outskirts of every country town, solar panels on every new house, factory or community building and solar thermal plants on the outskirts of each of the capital cities. Certainly they won't be the final answer, immediately, but they would go some way to minimising our fossil fuel usage. If biofuels can be developed at the same time, all the better.

Just a quick reminder, in a little over six years, we have deployed almost 2 GW of wind energy in Australia even though the industry has been hamstrung by ridiculous regulations and politically inspired delays. I haven't checked the up-to-date figures on overall solar installations. In that time around the world, no nuclear power plants have been constructed in the same time period.

Hi Blair - accept your definition of Armageddon. I don't think AGW by itself offers the prospect of the end of humanity full stop - although the fights for limited food and water resources under a worst case AGW scenario might be an issue.

My concern is the impact on our civilisation as we know it.

I agree with you that a major advantage of wind and solar PV is their ability to deploy in small elements rapidly - but you should not rule out SMRs

http://www.gizmag.com/small-modular-nuclear-reactors/20860/

which can also play a more rapid role if we let them

Fortunately, our midwestern drought has brought home one major flaw in the "biofuel" concept, and our military may not be renewing their subsidized use of it.

Guess we up here should check with you down there about our internal energy matters first, eh?
;]
Your points are ____ ?

20% is the nominal, consumer-grade system that's under $1/W today. NREL's graph for 2011 shows more expensive 2-junction systems doing over 30%, while concentrating systems achieve over 40%. Anything now above 30% is expensive and dedicated to military/space applications,, but that will change, as more systems use more of the solar frequency spectrum with cheaper designs.

Remember, >2% of earth'[s land has human structure on it, so even at 20% it's easily possible to meet all peak daytime loads -- no land consumed. Even NYC was recently laser scanned and judged able to meet 1/2 its peak summer day loads with just rooftop solar PV.

This is why solar/wind 'farms' are meaningless wastes of natural spaces. Solar thermal is even worse because it drives a heat engine, thus loses most of the solar input.

Went for the bait, eh David?
;]
Yes, all nuclear yields heat -- have you between studying on the sly, mate?

If so, you should know the operating temperature is key to minimizing waste heat and maximizing efficiency. Solar thermal can only reach efficient temps when the Sun is on. Otherwise, any stored heat energy fades into inefficient generation. so, here in Calif. some solar thermal sites actually have gas mains, to allow efficient generation when the Sun is off. Too bad they also produce CO2, eh? Also too bad that any solar thermal, as you know, must waste considerable power in distant transmission and conversion.

For your yard, or better, your basement, sure David!
;]

Peter - I'm sure you know more about acqueous chemistry than I do - but isn't it true that CO2 will dissolve more readily in sea water than in surface fresh water because the higher concentrations of carbonate ions in sea water mean the dissolving reaction of CO2 + Carbonate + H20 will go faster?

http://www.atmosphere.mpg.de/enid/1vd.html

If that's true I would not expect to see as big an effect in Victorian surface fresh water?

I don't think the oceanic pH drop is in dispute. But I agree the concerns are far from certain

http://www.annualreviews.org/doi/abs/10.1146/annurev.marine.010908.163834
Ocean Acidification: The Other CO2 Problem

Annual Review of Marine Science

"Rising atmospheric carbon dioxide (CO2), primarily from human fossil fuel combustion, reduces ocean pH and causes wholesale shifts in seawater carbonate chemistry. The process of ocean acidification is well documented in field data, and the rate will accelerate over this century unless future CO2 emissions are curbed dramatically. Acidification alters seawater chemical speciation and biogeochemical cycles of many elements and compounds. One well-known effect is the lowering of calcium carbonate saturation states, which impacts shell-forming marine organisms from plankton to benthic molluscs, echinoderms, and corals. Many calcifying species exhibit reduced calcification and growth rates in laboratory experiments under high-CO2 conditions. Ocean acidification also causes an increase in carbon fixation rates in some photosynthetic organisms (both calcifying and noncalcifying). The potential for marine organisms to adapt to increasing CO2 and broader implications for ocean ecosystems are not well known; both are high priorities for future research."

Which indicates a concern - but not a certain problem

http://oceanacidification.wordpress.com/2009/11/30/vulnerability-of-marine-biodiversity-to-ocean-acidification-a-meta-analysis/.

Hendriks, I. E., Duarte, C. M., & Àlvarez, M., 2009. Vulnerability of marine biodiversity to ocean acidification: A meta-analysis. Estuarine, Coastal and Shelf Science in press doi:10.1016/j.ecss.2009.11.022.

"The ocean captures a large part of the anthropogenic carbon dioxide emitted to the atmosphere. As a result of the increase in CO2 partial pressure the ocean pH is lowered as compared to pre-industrial times and a further decline is expected. Ocean acidification has been proposed to pose a major threat for marine organisms, particularly shell-forming and calcifying organisms. Here we show, on the basis of meta-analysis of available experimental assessments, differences in organism responses to elevated pCO2 and propose that marine biota may be more resistant to ocean acidification than expected. Calcification is most sensitive to ocean acidification while it is questionable if marine functional diversity is impacted significantly along the ranges of acidification predicted for the 21st century. Active biological processes and small-scale temporal and spatial variability in ocean pH may render marine biota far more resistant to ocean acidification than hitherto believed"

I think you will find the concerns are still being investigated

http://channelislands.noaa.gov/sac/pdf/cwg-oar.pdf

snippet "Recent scientific research, modeling and analysis clearly indicate a further drop in the pH of 0.3-0.5 by the end of the 21st century if present anthropogenic influence continues.36
Preeminent researchers are largely in agreement that this magnitude and rate of change is very significant, even in the Earth’s geologic time scale."

So it's not only the magnitude but the rate of change.

There's a useful table at the end of the above PDF that sets out the challenges

Hi Mark,

The answer to your first question is a simple no. On the contrary, I would expect CO2 to dissolve more rapidly in fresh water than sea water if it was simply a diffusion process dominated by Henry's Law - which it isn't.

One of the things that does distinguish fresh water from sea water is numbers of algae they can support. Algae are a very important component in aqueous carbon chemistry - a factor that is frequently overlooked. Compared with surface waters sea water is generally more deficient in nutrients. However localised variations in the nutrient levels in sea water do occur largely due to inputs from land masses, which explains fisheries that exist in particular areas.

My point is that the carbon cycle in aqueous environments is much more complex than the simple equilibrium models used by the references you cited.

Cheers

Interesting - I will do some more desk research. Do the Algae alter the water chemistry (i.e. increase dissolution of the CO2) or do they uptake the CO2 directly via photosynthesis? If it's the latter wouldn't that explain why the victorian surface water pH is not dropping but could still account for CO2 absorption?

It's a fascinating topic. Regardless I think the current research on oceanic pH can be fairly summariosed as

(1) Oceans absorb a lot of the excess atmospheric CO2
(2) It is lowering the Oceanic pH - so far by a small amount (0.1) but could be projected to be larger (0.3) by the turn of the century
(3) Such a chemistry change represents a risk that science cannot yet reliably quantify to shell forming biota at the bottom of the food chain
(4) Some evidence suggests the adapatability to such changes across the diversity of such biota is more robust than at first feared
(5) A risk area to watch and study more

Algae are plants Mark. They are like land based plants. They use photosynthesis to produce cells from CO2. There are many varieties each of which depend upon other nutrients. For example green algae thrive where sufficient nitrogen and phosphorous are present. But if the nitrogen available is too low ( in the form of nitrate) then the dominant population can switch very quickly to nitrogen fixing species such as the blue green algae (which are often brown). Blue green algae are responsible for the red tides that we occasionally see in the oceans. They also appear in eutrophic fresh water systems.

Algae are therefore intimately involved in the carbonate chemistry of aqueous systems.

Broadly I accept your summary of the literature. But I remain sceptical of the prediction of pH reductions, and even more sceptical of the predictions of the implications for this on ocean organisms. I don't know whether or not you have ever measured the pH of aqueous samples. It is actually not an easy measurement to make, despite the sophistication of glass electrodes,and it is also temperature dependent. Hence my scepticism about a claimed reduction of 0.1 units!

Hi Peter - yes, I fully understand they are plants. I even gather that their photosynthetic capabilities exceed those of land based plants by a wide margin - so they are more efficient at CO2 absorption and sunlight conversion than, say, corn or trees (alternative sources of biomass for synthetic fuel).

I've seen several studies investigating algae use as an excellent form of carbon sequestration.

What I haven't seen, and you havent elaborated, is how their photosynthetic chemistry in fresh water might alter the water pH?

The quoted 0.1 ph reduction comes from the GLODAP DIC database

http://www.gfdl.noaa.gov/bibliography/related_files/rmk0401.pdf

While globally ocean pH varies from around 7.9 to 8.2

http://dge.stanford.edu/labs/caldeiralab/Caldeira%20downloads/RoyalSociety_OceanAcidification.pdf

nevertheless, because of multiple sampling and averaging it is still meaningfull to talk about a 0.1 average reduction (statistical averaging over a very large dataset can signifricantly reduce uncertainties provided no systematic biases are present - unlikely given a very large set of independent measures)

Algae can create significant biomass much more rapidly than land based plants. Also, in terms of their biochemistry they are mostly lipids which is why they are so interesting with respect to biofuel production. Likewise they can be cultured - another attraction for biofuel production. The land areas required are not excessive and also such systems can be built alongside power stations and sewage plants to utilise their effluents for nutrients. It is a promising area and there is some serious R&D underway,tots.lyfunded by commercial interests to develop the technology.

They have a major effect on the pH of Melbourne's water storage in that they not only absorb CO2 in the upper lithosphere of the storage but they also release CO2 in the depths of the storages when they die and sink. One should not forget that there is also a population of phytoplankton that feed off the algae that are part of the cycle. the same applies to the oceans.

As a metrologist I note the references you have cited re ocean pH. If you have enormous amounts of data small differences can appear significant statistically. That does not mean they are. Statistics well tell you that.

But, a really big but (no pun), photosynthesis, even in best algae is no better than 10%. 20% solar PV can be put existing structures with no further processing or combustion loss.

Running the US peak demand for vehicles takes no land via PV, but more land in equivalent area for any photosynthesizing organisms,

And, algae are mostly water, making extraction energy an additional loss. And, combustion in engines adds a horrendous loss on top iof all that.

The biology, physics & environmental impacts make biofuels of any kind unrealistic.

These are the facts, inconvenient as they may be.

Hi Peter, the issue is with seawater, not fresh water bodies. The Carbonate Cycle depends indeed on CO2 from the air, but as you likely know, living creatures of the sea that form carbonate shells/skeletons cannot do so at pH levels around 8 or below.

The N. Atlantic is now about 8.1pH. It has been moved from >8.2 in less than 100 years. It has 0.1 left to go before the bulk of the base food-chain animals cannot live. Nordic fisheries already see these effects and there have been many recent reports on the problem.

It's not quite so bad in other oceans, but the point is that CO2 in the air has been increasing and its take-up by seas will continue even if we shut off all combustion tonight, worldwide.

The issue of what to do has come up because this has the most immediate and most serious effect on sea species and humanity, given that humans derive ~20% of food protein from the sea and 80% of humanity depends to some large extent on sea food.

The other side of the problem is that calcification by plankton, etc. is where CO2 goes on its way to sea floors to form limestone after the creatures die.

Not only will <8.1pH begin to shut down food supplies worldwide, it will shut down long-term natural CO2 sequestration. This is nearer future than sea rise or perhaps serious climate change.

The solutions are increasingly drastic as we fail to get the fact that all net combustion must stop and pH will drop further regardless of such a hard stop.

Here are some refs:
http://online.wr.usgs.gov/calendar/2012/mar12.html
www.ocean-acidification.net/
http://tinyurl.com/6mtd8db
www.noaa.gov/video/administrator/acidification/index.html
www.bbc.co.uk/news/science-environment-18938002

You can email me and I'll send you more, if you like. Last name at sbcglobal dot net

PS, what's a"red tick" -- another Aussie beer?

Hi Peter - I understand metrology quite well, having headed the Kodak R&D metrology group in Australia for a number of years.

Enormous amounts of data do not, in of themselves, make small differences appear statistically different. They do enable you, within limits, to increase your precision and proper ANOVA tests on the various data sets should tell you whether or not differences are real.

In the case of world wide oceanic pH - if the differences over time measured were not real, but due to a staistical artefact - one would expect such differences to be randomly distribued geographically. They aren't

http://dge.stanford.edu/labs/caldeiralab/Caldeira%20downloads/RoyalSociety_OceanAcidification.pdf

see figure 4.

So I suggest to your skepticism about the 0.1ph change is unwarranted.

However the impact is another question. http://www.ocean-acidification.net/FAQeco.html

I think it is fair to say though that we do not properly understand the impacts

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0028983

Most of the studies that have been done on impacts have been in lab, not in situ, and there is reasonable evidence (see above) that many species of concern experience natural variability across their cycle "demonstrating that resident organisms are already experiencing pH regimes that are not predicted until 2100."

So, it is not certain, yet, that it is a big a problem as first thought

Alex I think you are oversimplifying - as stated elsewhere efficiency and cost have to be weighed together.

Hi Mark,

I am curious. Have you actually read the references you cited? If not I suggest you take the time to do so. I would love to discuss this with you over a cup of coffee.

I am happy to defend my scepticism concerning the postulated 0.1 reduction in ocean pH. And I disagree - enormous amounts of data can suggest significant differences where none exist. You simply have to look at the mathematics to appreciate this.

But this forum is really not suited to such a complex discussion.

Alex,

I will email you - this is a discussion that needs to be taken off-line where it is not disrupted by extraneous comments.

I am interested in pursuing your sources. You have made some comments that I think are alarmist and in fact very wrong. I will be in touch shortly.

PS:

Red ticks are those negative numbers that so often appear against your comments.

Agree this is not a forum. I confess I have only skimmed the papers. And I think you have misunderstood me (or I have not communicated well or both). I agree that enormous amounts of data CAN suggest differences where none exist - I;ve seen it myself. The question is whether or not they do in this instance. I believe that if the variance was there it would be randomly distribued over the global geography. Based on the final presented analysis in the global graphs (Fig 4 in the royal society paper) this does not appear to be the case - but I confess i don't have access to the raw data to confirm this. One would need to check the original references and papers from the GLODAP database.

Regardless I think the latest science suggests that impacts, at first thought to be very bad, were based on lab exposure of organisms and not in-situ. And more recent work suggests natural variation for many of the shell forming organisms of concern is at least as large as the modelled projections for pH decrease by 2100.

In other words the tolerance of the organisms in the real world may be sufficiently robust to downplay the concern - but more research is warranted since while the risk may be lower than originally thought the hazard/impact is still a major concern

Perhaps we really should discuss this over a cup of coffee and a bagel. My invitation remains open.

It is not really about the tolerances of the organisms - what is more important is their evolution and exactly how they produce calcareous structures. There is a heap of predictions based on rather shonky science - this is but one example. I would love the opportunity to discuss this further. But not here

Given that it seems to be largely agreed that the EROEI ratio of all current renewable energy sources is 10 or less, your are effictively arguing, in my household income analogy, that getting 10 $1 per hour jobs and working double hours in each will allow us to afford to live a life style equivalent to of Bill Gates.

The fact is that current renewable energy sources cannot sustain our current population and level of economic activity and consumption in the absense of fossil fuel energy.

Don't know where you get solar PV is about as inefficient as algae making oils at <10% efficiency, which are then burned at less than 40% efficiency in vehicles, Luke.

With PV, we're dealing with physics in all its glories -- quantum, electronic, optical...

With algae, we're dealing with trying to use some that was never intended to provide us power, and to do it via the most inefficient energy-conversion method -- combustion in an engine.

Solar PV is now 20% efficient on roofs at <$1/Watt, and thus 0 land costs. Algae is inefficient before the first harvest is made, from some dedicated space. unusable for anything else, with unrecoverable processing energy unusable for anything else, and waste heat in combustion, unusable for anything but planetary warming.
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