The California Independent System Operator (CAISO) has suggested, in a response filed (pdf) with the California Public Utilities Commission (CPUC), that “refinements [to an earlier analysis] indicate a greater operational deficiency reaching maximums of 2,300 MW, 4,400 MW, and 4,700 MW in 2020, 2021, and 2022, respectively.”

The grid manager of 90% of California’s electricity demand made two broad recommendations:

Move forward with efforts to extend the once-through-cooling regulation

compliance dates for existing generation resources. Develop a procurement plan for 2020-2022 to meet reliability needs and facilitate the

retirement of any generating unit that receives an OTC compliance date extension: Direct resource adequacy procurement for uncontracted resources that are operational or mothballed; Direct increased resource adequacy procurement for uncontracted import resources; Ensure resources under construction are on-track for their online dates so that they do not exacerbate reliability concerns; and Direct procurement for new resources.

The report noted a prior analysis done by utility Southern California Edison (SCE), which found that generally:

The peak hour of the year occurs consistently in September. In 2020 and 2021, the projected peak falls within hour ending 17 (based on P.S.T. or 6:00 p.m. P.D.T.). By 2022, the peak shifts to hour ending 18 (based on P.S.T. or 7:00 p.m. P.D.T.).

As such, the analysis looks at various hours within that period when determining what the shortfall could be. From the report (below image), various electricity sources are shown, with solar power dropping (in yellow) from the left to the right as the evening progresses leading to the shortfall. Page 20 of the documents breaks out the capacity by source with number values, pages 26-28 break the same hourly data below into numbers as well.

In 2020, for the hours ending 17 through 19, the resource adequacy-backed energy is 2,200 MW, 2,300 MW, and 1,500 MW less than the hourly capacity need. In 2021, for the hours ending 17 through 20, the reliability gaps increase to 4,000 MW, 4,400 MW, 3,800 MW, and 2,200 MW. Then in 2022, for the same hours as 2021, the gap is 3,900 MW, 4,700 MW (peak value), 4,200 MW, and 2,600 MW.

And all of this led to a most astute observation by energy futurist/analyst/writer/speaker and EV-Grid Manager at @RockyMtnInst, Chris Nelder:

Put another way… Cali just issued a shadow RFP for 4.7 GW of RE/EE/storage. Great opportunity for developers. https://t.co/13beHBgvGt — Chris Nelder (@chrisnelder) August 14, 2019

And in a state like California, which has aggressive goals of reaching 50% renewables and 100% clean energy by 2045 – you’ve got to wonder if Nelder is right, and how exactly this is going to work. As CAISO said in its report, the sun goes down and the peak is too late for even west-facing solar panels.

Another consideration, not referenced directly in the document, is that Pacific Gas and Electric Company has requested that its bankruptcy court judge approve an 11% discount for the mNOC AERS energy storage project and an additional 15 months to deploy, while for the Hummingbird battery a 10% discount and 12 extra months to deploy have been requested. These projects were scheduled to be online in 2019 and 2020.

The document notes that within the state, 1,047 MW of the 1,597 MW in nameplate capacity contracted to come online before August 2021 is solar, but “by the later peak hour in 2022 (hour ending 18 or 7 p.m.) average solar generation [is reduced] to only 0.04 percent of maximum generation.”

CAISO’s future capacity queue, (image at left), includes 43 GWac of solar power and 36 GW of energy storage; however, most of it is back loaded. As well, most of the projects don’t have all documents in place.