In recent years, Germany has led the world in the adoption of solar power. Now the country’s national energy agency is concerned that Germans’ love of sun beams may paradoxically leave them in the dark.
In an interview with Berliner Zeitung on Oct. 17, Stephan Köhler, head of Germany’s energy agency DENA said harnessing the sun’s energy could overload the country’s electricity grid. Solar power, like wind power, is intermittent; it spikes on clear days around noon when the sun is high in the sky. But in Germany, demand for electricity is low around mid-day and high in the evenings (when people wake up, or come home from work, and turn on electrical appliances). That discrepancy, Köhler warns, could trigger blackouts.
That hasn’t been a problem thus far because surges in solar power are accommodated by switching off conventional power station generators. But Köhler warns that if solar continues to be built at its current rate, eventually it will exceed demand and overwhelm the system.
Germany’s booming solar industry is the result of government subsidies that have encouraged German citizens and businesses to install panels and sell surplus electricity to the grid. In 2008, for instance, Germany installed about 2,500 megawatts out of the world’s 5,158. According to the New Scientist, “uptake has been so rapid that solar capacity could reach 30 gigawatts, equal to the country’s weekend power consumption, by the end of next year.”
“We need to cap installation of new panels,” a spokesperson for DENA told New Scientist.
The German Solar Industry Federation has refuted this statement, saying that solar panels relieve pressure on the country’s aging electricity grid because the power they produce is used close to the source. It concedes, however, that Germany’s grid needs to be strengthened in some rural areas.
Germany’s problems may be unique to that country, says Daniel Davies, chief technology officer at Solar Century, a UK-based designer and installer of PV systems. He points out that in California and many American urban centers, electricity demand peaks around mid-day–when Californians switch on their air conditioning (air condition in Germany, as in much of Europe, is relatively rare). He also says that in some countries—such as the UK—solar installations come with a contract with the network operator; if solar is predicted to cause an excess in supply then consumers pay a surplus to upgrade the grid.
Because of the variability of supply, renewables should spur region-wide grids, Davies and others say. For example, Britain and Scandinavia could set up a grid to share wind power as weather systems move across the region. Ditto southern Europe and sunny weather. To Davies and other solar enthusiasts, this could help even out the supply side, and help ensure that solar remains a bright idea in the battle against climate change.