Solar is displacing gas in California’s summer electricity mix

Today the U.S. Department of Energy’s Energy Information Administration (EIA) released a new analysis which finds that increased solar and other renewable energy generation has contributed to a decline in thermal generation over the course of June, July and August in California.

Specifically, EIA notes that in the area managed by the California Independent System Operator (CAISO) thermal generation fell 20% compared to the summer of 2015, with reduced natural gas generation representing “almost all” of this decline.

Image: EIA
Image: EIA

And while hydroelectric generation has increased due to higher rainfall, EIA notes that solar has led the increase in non-hydro renewable energy generation. The agency calculates that utility-scale PV on the CAISO grid increased by 1.4 GW between June 2015 and June 2016, with distributed PV rising another 1 GW. The result is that utility-scale solar alone represented 13% of the 63 GW of the grid’s net summer capacity as of June 2016.

It is clear that this increase in PV generation is also creating challenges during the late afternoon, as solar production rapidly declines and the evening demand peak begins.

However, during the past few years California has been studying and implementing multiple strategies to mitigate the steep rise in demand for thermal generation caused by this phenomenon. Measures already underway include putting online more fast-ramping gas plants and beginning large-scale deployment of energy storage.