SDG&E’s 2045 decarbonisation roadmap: California needs 40GW of BESS and 4x electricity capacity

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Californian investor-owned utility San Diego Gas & Electric (SDG&E) has released its decarbonisation roadmap study, which says the state will need to quadruple its electricity capacity from 85GW in 2020 to 356GW in 2045.

“The Path to Net Zero: A Decarbonization Roadmap for California” was released yesterday (5 April) and offers recommendations designed to help meet the state’s aim of carbon neutrality by 2045.

To achieve this the state will need 40GW of battery energy storage deployment but also 20GW of dispatchable generation from green hydrogen, the utility added. Some 2,728MW of storage is grid-connected as per California ISO’s (CAISO’s) most recent monthly statistics for March, but there is no generation from green hydrogen.

The report, available on its website, says that alongside electrification of sectors like transportation and buildings, electric reliability is also important part of the green transition. The press release claims SDG&E’s report is the first to incorporate the utility industry standard for reliability, which means only one power outage every 10 years.

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Boston Consulting Group, Black & Veatch and UC San Diego Professor David G. Victor provided technical support to SDG&E for conducting the study.

California needs to decarbonise 4.5x as fast as it has been doing over the past decade to achieve its goals, SDG&E said. Electric generation capacity needs to quadruple from the 2020 figure of 85GW to 356GW in 2045, half of which will be solar.

The figure differs slightly to California ISO’s own recent figures which said it needs 37GW of battery energy storage systems and 4GW of long-duration storage by 2045 to achieve its goals. Other, older figures have pegged the long duration capacity alone needed by then at 55GW.

However, only 2.5GW of that energy storage will be in SDG&E’s service area with an interim 2030 target of 1.5GW. By the end of 2020, the figure stood at 331MW, both utility-owned and third-party.

SDG&E and CAISO figures on the necessary storage deployment for 2045 both equate to storage providing over 10% of power capacity the state will need by then according to SDG&E (356GW).

SDG&E estimates that demand for green hydrogen in California will reach 6.5 million metric tonnes by 2045, 80% of which will be used to enhance the reliability of electricity supply.

The report also says that significant investments in the region’s electricity infrastructure will be needed to support the higher electricity capacity. In its modelling, California will be importing 34GW of renewable power from other states and that a larger interconnected western grid is critical to ensure the long-term reliability of California’s electricity system.

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