Written by : BRYAN ESTERLY , INFRASTRUCTURE ANALYST , THE SUSTAINABILITY ACCOUNTING STANDARDS BOARD

PG & E HAS PROPOSED shuttering California ’ s last remaining nuclear power plant , calling on energy efficiency , renewables , and energy storage to take center stage . The interaction of state regulatory policy and energy economics has led to the proposal , which would take 18,000 gigawatt hours ( GWh ) of annual carbon-free electricity output offline in less than 10 years . Understanding PG & E ’ s proposed approach to meeting demand , absent the plant that produces nearly 9 percent of the state ’ s electricity , is useful for understanding the opportunities and challenges of driving efficiency and transitioning to renewable energy across the country .

Carbon free , but not “ renewable ” California ’ s Renewable Portfolio Standard ( RPS ) requires 50 percent of utilities ’ power to qualify as renewable by 2030 . According to state law , nuclear energy does not qualify . Since renewable energy , such as solar and wind , is typically an intermittent energy source , utilities and grid operators need to supplement renewables with compatible energy

13