California’s energy agencies on Sept. 5 moved forward with formalizing a plan to implement the renewables and zero-carbon goals set out in SB 100. But nuclear proponents allege that the plan could increase natural gas usage.

The California Energy Commission, the California Public Utilities Commission and the California Air Resources Board will create the plan based on the requirements of SB 100, which was passed in September 2018 and which requires 100 percent zero-carbon electricity by the end of 2045.

The plan is required to describe ways in which the state will meet its clean-energy goals while not increasing carbon emissions elsewhere on the Western grid. The implementation plan is due to the state Legislature by Jan. 1, 2021, and is required to be updated every four years.

But Californians for Green Nuclear Power, a group with a stated mission of providing “safe, carbon-free nuclear power while keeping the Diablo Canyon Nuclear Power Plant open,” said the state’s natural gas-fired generators will need to run on a “stop-and-go pattern” more frequently as more renewables come onto the grid, and this pattern will “yield higher natural gas consumption and higher emissions.”

“California’s natural gas-fired generation produced about 90 TWh of electricity [in 2011], but that value soared to 120 TWh in 2012, with the most important factor being the loss of about 18 TWh per year previously supplied by San Onofre Nuclear Generating Station generation,” Gene Nelson, government liaison for Californians for Green Nuclear Power, said. “Under this [new energy resource plan], the reliable supply of essential baseload power will be met by burning natural gas, more than if Diablo continued to operate, increasing carbon dioxide emissions by 9 million tons annually.”

However, natural gas demand in the state is forecast to decrease over the next 10 years as more renewables come onto the grid, falling from about 13,000 million therms in 2019 to about 12,800 million therms in 2030, according to the CEC.

Nelson said the joint agency plan should call for keeping Diablo Canyon in operation well beyond operator Pacific Gas & Electric’s proposed 2025 shutdown because the plant could act as a reliable power source before large energy storage projects are available. The plant’s decommissioning process is estimated to cost about $4.8 billion and would result in a net economic loss of about $77 million annually to San Luis Obispo County, according to a June 2019 UC Berkeley report prepared for the CPUC.

The team of nuclear power proponents also expressed concern about future energy storage projects, stating that some integrated energy-resource approaches assume “massive energy storage will be available for intermittent resources within 10 to 20 years.”

“There is nothing in the record or in the public domain that indicates the massive quantities of energy storage are available now or will be available shortly, to make an appreciable difference in the deployment of renewables and hence emissions,” Nelson said.

In areas around the San Onofre plant, the CPUC approved energy storage procurement projects of between 600 MW and 1,000 MW capacity, including 61 MW of energy storage at Aliso Canyon.

The CEC last month also said the joint agencies are looking into new definitions for the term “zero-carbon technology” in order to help meet the state’s goal of supplying 100-percent zero-carbon electricity to customers by Dec. 31, 2045 (see CEM No. 1552).