This is praiseworthy and also highly ambitious. California is mandating 100% renewable or zero emission energy produced in-state by 2045. (The bill has passed the legislature and I’m assuming Gov. Brown will sign it.) Thus, California must find a replacement for its carbon power sources. It also plans to put millions more zero emissions vehicles on the road, although how this will be done is unclear.
The question is, how will this be achieved? Solar energy peaks during mid-afternoon. Wind power is also variable. The grid has to be kept in constant balance between supply and demand. Perhaps excess solar and wind power can be stored in batteries. However that’s mostly not happening yet and would be expensive. Baseline power currently is mostly generated by natural gas in California. Whatever replaces it has to be continuous 24/7 power. The only real candidate to do this is nuclear power, unless an alternative source can be found.
California’s many solar power plants already generate more electricity on many days than the state can use, forcing grid operators to block it from the grid. According to the Natural Resources Defense Council, an environmental group, California wasted enough renewable power during the first seven months of 2018 to power San Francisco for 20 days.
And the state’s demand for electricity usually peaks in the late afternoon and early evening — precisely when solar power disappears from the grid. Although California’s wind farms generate most of their electricity at night, there remains a gap that conventional power plants burning natural gas must fill.
A recent report prepared for the California Energy Commission found that relying on zero-carbon sources for 100 percent of the state’s energy in 2050 would be “cost-prohibitive” without nuclear power, better ways to store large amounts of energy, and technology that can capture the greenhouse gas emissions from conventional power plants.