The myth that renewable energy sources can’t meet baseload (24-hour per day) demand has become widespread. After all, the wind doesn’t blow all the time, and there’s no sunlight at night.
But detailed computer simulations, backed up by real-world experience with wind power, demonstrate that a transition to 100% energy production from renewable sources is possible within the next few decades. The baseload issue can be solved by reducing baseload demand,having some renewable energy sources that can supply baseload power and increasing the proportion of flexible peakload plant in the generating mix.
Reducing Baseload Demand
We do not currently use our energy very efficiently. For example, nighttime energy demand is much lower than during the day, and yet we waste a great deal of energy from coal and nuclear power plants, which cannot be powered up quickly. Some are kept running through the night heating water. These plants can be replaced with solar hot water and renewable electricity.
Baseload demand can be further reduced by increasing the energy efficiency of homes and other buildings.
Renewable Baseload Sources
Some renewable energy sources are just as reliable for baseload energy as fossil fuels. For example, bio-electricity generated from burning the residues of crops and plantation forests, concentrated solar thermal power with low-cost thermal storage (such as in molten salt), and hot-rock geothermal power.
In fact, bio-electricity from organic residues already contributes to both baseload and peak-load power in parts of Europe and the USA, and is poised for rapid growth. Concentrated solar thermal technology is advancing rapidly, and a 19.9-megawatt solar thermal plant opened in Spain in 2011 (Gemasolar, which stores energy in molten salt for up to 15 hours.
Addressing Intermittency from Wind and Solar Photovoltaics
Wind power already supplies over 21% of Denmark’s electricity and 15% of Spain and Portugal’s.
Although the output of a single wind farm fluctuates greatly, the fluctuations in the total output from a number of wind farms geographically distributed in different wind regimes are much smaller and partially predictable.
Modelling has also shown that it’s relatively inexpensive to increase the reliability of the total wind output to a level equivalent to a coal-fired power station by adding a few low-cost peak-load gas turbines that are run on renewable biofuels and are operated infrequently, to fill in the gaps when the wind farm production is low.
Current power grid systems are already built to handle fluctuations in supply and demand with peak-load plants such as hydroelectric and gas turbines which can be switched on and off quickly, and by reserve baseload plants that are kept hot.
Recent studies by the US National Renewable Energy Laboratory found that wind could supply 20-30% of electricity, given improved transmission links and a little low-cost flexible back-up.
Global Case Studies
Approximately half of the goal is met through increased energy efficiency to first reduce energy demand and the other half by switching to renewable energy sources for electricity production.
Stanford’s Mark Jacobson and UC Davis’ Mark Delucchi published a study in 2010 in the journal Energy Policy examining the possibility of meeting all global energy needs with wind, water, and solar (WWS) power. They found it would be plausible to produce all new energy from WWS in 2030, and replace all pre-existing energy with WWS by 2050.
Jacobsen and Delucchi project that when accounting for the costs associated with air pollution and climate change, all the WWS technologies they consider will be cheaper than conventional energy sources (including coal) by 2020 or 2030, and in fact onshore wind is already cheaper.
An ill wind is no blow to baseload power
Summing up, arguments that renewable energy isn’t up to the task because “the Sun doesn’t shine at night and the wind doesn’t blow all the time” are overly simplistic. Several renewable electricity technologies can supply baseload power. The intermittency of other sources such as wind and solar photovoltaics can be addressed by interconnecting power plants which are widely geographically distributed and by coupling them with peak-load plants such as gas turbines fueled by biofuels which can quickly be switched on to fill in gaps of low wind or solar production. Several regional and global case studies – some incorporating modeling to demonstrate their feasibility – have provided plausible plans to meet 100% of energy demand with renewable sources.