Battery Arbitrage

Solar is powering a large share of California’s energy needs during the day and batteries are now powering a significant share at night.

NYTimes: Since 2020, California has installed more giant batteries than anywhere in the world apart from China. They can soak up excess solar power during the day and store it for use when it gets dark.

Those batteries play a pivotal role in California’s electric grid, partially replacing fossil fuels in the evening. Between 7 p.m. and 10 p.m. on April 30, for example, batteries supplied more than one-fifth of California’s electricity and, for a few minutes, pumped out 7,046 megawatts of electricity, akin to the output from seven large nuclear reactors.

California’s electricity deregulation had a rocky start but notice that it is paying off today because what is happening is that prices are low at mid-day when the sun is shining and they rise in the evening. Power companies profit by using batteries to arbitrage these prices differences. Thus, power companies have been willing to make huge investments in battery technology.