Note: Data are for the California region, which includes electric power markets regulated by the California Independent System Operator (CAISO) and other balancing authorities operating largely in California. In California wholesale electricity markets, natural gas-fired electricity generation helps to balance fluctuations in electricity demand with daily cycles in solar-powered electricity generation. Natural gas and solar are the two most prevalent sources of electricity generation in California; however, solar generation is non-dispatchable. Grid operators in the state use natural gas and, to a lesser extent, hydroelectricity and electricity imports from neighboring areas to balance changes in electricity demand. Both demand for electricity and output from natural gas-fired power plants in California are often highest in the afternoon and early evening, between 4:00 p.m. to 7:00 p.m. Output from solar power will peak and then plateau by midday, rapidly declining by the evening as the sun sets. As solar output declines, natural gas-fired generators often have to ramp up, or increase their output, considerably.