Non-hydro renewables accounted for 18% of the total supply to the California Independent System Operator's (ISO) grid in 2015, marking an increase of two percentage points from 2014.
Solar power plants were the main reason for the increase, the ISO said Tuesday. California added over 1.2 GW of solar power capacity to the grid in 2015 and, for the first time ever, solar farms reached a bigger share in generation than wind.
Solar power generation last year was up by about 38% and thus hit a share of nearly 7% in total supply. Wind’s share was about 5%, similar to that of geothermal and of hydropower generation.
California brought online zero megawatts of natural gas-fired power in 2015, while it retired just over 1 GW of gas plants. Still, natural gas remains the state’s main source of electricity.
The ISO said that thanks to a 40% fall in natural gas prices, moderate loads and several hundred MW of new peak summer generating capacity, wholesale costs remained low and highly competitive.