California needs clean firm power, and so does the rest of the world

The report assesses California's path to a net-zero carbon economy by 2045, specifically examining the necessity of 'clean firm power'—zero-carbon electricity that is available on demand regardless of weather. Using three different optimization models (RESOLVE, urbs, and GenX), the authors find that relying solely on wind, solar, and batteries would require nearly 500 GW of capacity and increase wholesale electricity rates by approximately 65%. In contrast, integrating 25-40 GW of clean firm power—such as nuclear, geothermal, or gas with carbon capture and storage (CCS)—can maintain costs similar to today's levels (around 9 cents/kWh) while significantly reducing the land and transmission infrastructure needed. The report concludes that a diverse portfolio of clean firm resources is the most cost-effective way to ensure grid reliability during extended periods of low renewable output, known as 'dunkelflaute'.

• Relying exclusively on wind, solar, and battery storage to meet 2045 demand would require nearly 500 GW of power-generating capacity, which is approximately six times California's current total generating capacity of 80 GW.
• A system based only on currently available renewable energy and storage technologies is estimated to increase wholesale electricity rates by about 65% compared to today's rates.
• Integrating 25-40 GW of clean firm power—roughly the size of California's existing gas fleet—can enable a 100% carbon-free supply by 2045 with generation and transmission costs of 7-10 cents per kWh, comparable to the current average of 9 cents per kWh.
• Portfolios including clean firm power are significantly more land-efficient, requiring between 625 and 2,500 square miles for utility-scale solar and wind, whereas a renewables-only system would require over 6,250 square miles.
• The need for new in-state transmission lines is reduced by a factor of approximately four when clean firm power is used; such portfolios require 2-3 million megawatt-miles of new lines, compared to 9 million megawatt-miles for a renewables-only system.
• While batteries are effective for hourly or diurnal fluctuations, they cannot cost-effectively provide the long-duration storage needed for 'dunkelflaute' events (extended periods of low wind and solar output) that can last for weeks.
• A diverse portfolio of clean firm power is more economical than relying on a single technology because different resources operate most efficiently at different utilization rates.

APA

Longa, J., Baik, E., Jenkins, J., Kolster, C., Chawla, K., Olson, A., Cohen, A., Colvina, M., Benson, S. M., Jackson, R., Victor, D., & Hamburg, S. (n.d.). California needs clean firm power, and so does the rest of the world. Clean Air Task Force. https://cdn.catf.us/wp-content/uploads/2021/09/21091928/SB100-clean-firm-power-report-plus-SI.pdf

Chicago

Longa, JCS, E Baik, JD Jenkins, C Kolster, K Chawla, A Olson, A Cohen, et al. California needs clean firm power, and so does the rest of the world. Clean Air Task Force, n.d. https://cdn.catf.us/wp-content/uploads/2021/09/21091928/SB100-clean-firm-power-report-plus-SI.pdf.

Wikipedia

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BibTeX

@techreport{longandcalifornia, author = {Longa, JCS and Baik, E and Jenkins, JD and Kolster, C and Chawla, K and Olson, A and Cohen, A and Colvina, M and Benson, S M and Jackson, RB and Victor, DG and Hamburg, SP}, title = {{California needs clean firm power, and so does the rest of the world}}, institution = {Clean Air Task Force}, url = {https://cdn.catf.us/wp-content/uploads/2021/09/21091928/SB100-clean-firm-power-report-plus-SI.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }