California has been experiencing an unprecedented boom in solar energy in recent years. The state’s major utilities now get 6% of their power from solar installations and on top of that, nearly a quarter million homes have solar panels on their roofs. All of this clean energy is surely a good thing, but it also presents a unique problem.
Solar power is intermittent: it only happens when the sun is shining. As a result, its contributions to the electricity supply are not steady and are not guaranteed. California’s utilities have a mandate to get 33% of their power from renewable sources by 2020. As the quantities of solar power grow, a problem emerges.
Conventional power sources like nuclear power and most gas-burning plants are called baseload sources. They run continuously. Unfortunately, they pretty much have to. It is a lengthy and complicated process to turn them on and turn them off. While they are running, if a huge amount of solar energy is simultaneously produced in the afternoon, it is possible that too much electricity would be generated. One can imagine a planned ramping down of conventional plants, but as the sun goes down and people get home, the result is a need for massive and abrupt ramping up of those plants.
There are solutions to this over-generation problem. They include sending excess power to other states, time-shifting the use of electricity, and most promisingly, the use of energy storage. California’s solar boom is creating the need for entirely new ways to manage the electrical grid. We need to know what to do when there is too much of a good thing.
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Photo, posted August 11, 2009, courtesy of Port of San Diego via Flickr.
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Earth Wise is a production of WAMC Northeast Public Radio.