Electricity transmission infrastructure planning over the next 20 years will be critical to meeting California's 2045 zero-carbon electricity goal, energy officials said at a June 2 joint agency workshop.
The California Independent System Operator has created a new 20-year transmission planning initiative that will consider building and vehicle electrification and potentially more aggressive natural gas-fired generation retirement to meet SB 100 goals, CAISO representatives said at the workshop. SB 100 is California's primary zero-carbon electricity generation mandate, stating that all retail electricity sales to end-use customers in 2045 must be generated from zero-carbon energy resources.
CAISO will use SB 100 models as the starting point for its 20-year transmission plan. The plan includes technical studies that are more general than the CAISO's existing 10-year transmission plan, representatives said in a separate May presentation. Creation of the 20-year transmission plan is meant to be a transparent process to help achieve SB 100 goals as well as aid the California Public Utilities Commission's integrated resource planning processes, representatives said. CAISO plans to publish a draft of the 20-year plan on Jan. 31, 2022.
California's electric grid capacity will triple by 2045, according to the California Energy Commission's SB 100 model, CEC staff member Liz Gill said at the workshop. Even so, the SB 100 model's projections are conservative because they do not rely on technology breakthroughs, Gill said. In 2045, the state should have about 10 GW of offshore wind capacity; about 12 GW of onshore wind; 70 GW of utility-scale solar; 49 GW of battery energy storage; and about 0.14 GW of geothermal, according to the model.
About 4.7 GW of natural gas generation should retire in the next two decades, although most of the state's natural gas capacity is retained under resource-adequacy requirements, CEC staff said (see CEM No. 1606). Gas generation would be primarily utilized for loads not covered by SB 100's zero-carbon target, such as transmission, distribution and storage losses and nonretail loads, staff said. Natural gas capacity is the most economic option for reliability needs under current resource assumptions, staff said.
Investor-owned utility representatives at the workshop said that natural gas generation will be needed in the long term to meet peak demand. However, gas generation should be decarbonized—i.e., it should include carbon capture and sequestration technology or biomethane, they said.
In March, the CEC, the CPUC and the California Air Resources Board published the first iteration of the SB 100 report. The first iteration does not consider electric grid reliability, Gill said. CAISO was not a primary stakeholder in the development of the report, CAISO spokesperson Anne Gonzales said in a previous email to California Energy Markets.
Dawn Weisz, CEO of community choice aggregator MCE, at the workshop said it is almost impossible right now to purchase certain renewable energy resources as RA resources due to various issues, including policy constraints. A lot of these resources, such as gravity energy storage and renewable hydrogen, are promising and probably essential to meet SB 100 goals, Weisz said. RA parameters could help bring more of these resources onto the grid and help to ensure customer costs don't increase, she said.
At this point in the SB 100 process, there is mutual recognition of the need to look more closely at the state's energy investments in order to move forward, CEC member Karen Douglas said.