Countdown to Shutdown

The Union of Concerned Scientists finds that California's current electricity sector planning is insufficient to replace the zero-emissions energy from the Diablo Canyon nuclear power plant, which is scheduled for retirement in 2024 and 2025. Without further action, the state faces a cumulative increase of 15.5 million metric tons of global warming emissions over the next decade, as existing natural gas plants fill the gap. The report recommends adopting a more ambitious 30 MMT emissions target by 2030 to guarantee full replacement and accelerate decarbonization.

• The retirement of the Diablo Canyon nuclear power plant, which provided 8 percent of California's in-state electricity generation in 2019, risks increasing cumulative global warming and air pollution emissions because current clean energy build-out plans are insufficient to replace its zero-emissions output.
• Under the least ambitious emissions pathway (46 MMT by 2030), the retirement of Diablo Canyon would lead to a cumulative increase of 15.5 million metric tons (MMT) of global warming emissions and 1,890 metric tons of NOx emissions over the next decade.
• The 46 MMT by 2030 emissions target is considered incompatible with state law because it does not reduce emissions enough to replace Diablo Canyon while simultaneously meeting the state's renewable energy goals; the target would need to be at most 43 MMT to ensure full replacement by 2030.
• More ambitious emissions targets significantly reduce or eliminate the emissions gap caused by the plant's closure: the 38 MMT pathway results in a cumulative increase of 5.1 MMT of global warming emissions, while the 30 MMT pathway produces no excess emissions and actually reduces cumulative emissions by 1.3 MMT over the decade.
• The most cost-effective resources for replacing Diablo Canyon vary by target: in the 46 MMT pathway, increasing wind build-out by 3,000 MW is the most efficient way to close the emissions gap, whereas the 30 MMT pathway relies more on geothermal, battery storage, and solar due to the limited availability of wind and pumped storage.

APA

Union of Concerned Scientists (2021). Countdown to Shutdown. https://www.ucs.org/sites/default/files/2021-02/countdown-to-shutdown.pdf

Chicago

Union of Concerned Scientists. Countdown to Shutdown. 2021. https://www.ucs.org/sites/default/files/2021-02/countdown-to-shutdown.pdf.

Wikipedia

{{cite report |author=Union of Concerned Scientists |title=Countdown to Shutdown |date=February 2021 |url=https://www.ucs.org/sites/default/files/2021-02/countdown-to-shutdown.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{unionofconcernedscientists2021countdown, author = {{Union of Concerned Scientists}}, title = {{Countdown to Shutdown}}, institution = {Union of Concerned Scientists}, year = {2021}, month = feb, url = {https://www.ucs.org/sites/default/files/2021-02/countdown-to-shutdown.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }