OUR MISSION: To provide our customers with high-quality, efficient and reliable water, power and sewer services in a manner that values environmental and community interests and sustains the resources entrusted to our care.
525 Golden Gate Avenue, 13th Floor
San Francisco, CA 94102
T 415.554.3155
F 415.554.3161
TTY 415.554.3488
Date: May 19, 2025
To: Commiss
ioner Kate H. Stacy, President
Commissioner Joshua Arce, Vice President
Commissioner Avni Jamdar
Commissioner Steve Leveroni
Through: Denn
is J. Herrera, General Manager
Barbara Hale, Assistant General Manager, Power
Michael Hyams, Deputy AGM, CleanPowerSF and Power Resources Catherine Spaulding, Deputy AGM, Customers and Planning From: Colten K
rieg, CleanPowerSF Operations
Dan Willis, Regulatory and Legislative Affairs
Subject: Annual R
eport to the California Energy Commission by Hetch
Hetchy Power and CleanPowerSF on their Sources of Electric Energy and Greenhouse Gas Intensity
Summary
Hetch Het
chy Power and CleanPowerSF will submit their respective Power Source Disclosure R eports for calendar year 2024 to the California Energy Commission no later than June 2, 2025, as required by statute. 1 The Power Source Disclosure Report shows the sources of energy used to meet electric demands as well as the greenhouse gas intensity of each retail electricity product. All California retail providers of electric energy are required to use a consistent method to calculate the greenhouse gas intensities of their products.
This memo summarizes the data reports that will be provided to the California Energy Commission.
1 California Public Utilities Code Sections 398.4 and 398.5.
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Hetch Hetchy Power
Hetch Hetchy Power provides two products for which separate Power Source Disclosure reports are required: (1) Hetch Hetchy Power and (2) Hetch Hetchy Premium.
(1) Hetch Hetchy Power
For calendar year 2024, Hetch Hetchy Power’s energy mix was 100% GHG - free hydroelectric generation. Hetch Hetchy Power generation came from its Holm, Moccasin, and Ki rkwood hydroelectric power plants , meeting 99% of customer needs, with the remaining 1% consisting of GHG-free hydroelectric power delivered by the Western Area Power Administration to serve Treasure and Yerba Buena Islands . The greenhouse gas emissions intensity of Hetch Hetchy Power was 0 pounds of carbon dioxide equivalents per megawatt -hour (CO2e/MWh).
Hetch Hetchy Power also generated Renewable Portfolio Standard- eligible electricity above its retail needs from in- city solar installations, biomass energy from the Southeast Cogeneration Plant, and from the Kirkwood hydroelectric facility. This surplus generation, totaling about 25,000 MWh, was sold into California's energy markets with Hetch Hetchy Power retaining the associated renewable energy credits. These credits can be used to meet Hetch Hetchy Power’s Renewable Portfolio Standard obligations in future years if needed.
(2) Hetch Hetchy Premium
For calendar year 2024, Hetch Hetchy Premium’s energy mix w as 100% GHG- free hydroelectric generation and met the requirements of the California Air Resources Board’s Low Carbon Fuel Standard Program . Hetch Hetchy Premium generation came from the Kirkwood hydroelectric power plant. The greenhouse gas emissions intensity of Hetch Hetchy Premium was 0 pounds of CO2e/MWh.
This Premium service allows the San Francisco Municipal Transportation Agency, the San Francisco International Airport, and the Port of San Francisco to receive additional credits under the California Air Resources Board’s Low Carbon Fuel Standard Program . This program rewards these entities for using clean electric energy instead of fossil fuels for transportation-related uses.
CleanPowerSF
The 2021 Mayor’s Climate Action Plan tasked SFPUC with providing San Franciscans 100% renewable and/or greenhouse gas (GHG)-free electricity Page | 3
supply by 2025. CleanPowerSF achieved this milestone in 2023 for all customers by providing 63 percent California Renewable Portfolio Standard- eligible electricity and 37 percent GHG-free electricity across its three products.
In 2024, CleanPowerSF’s electric energy mix was again comprised of 100 percent renewable energy – 90.4 percent Renewable Portfolio Standard- eligible and 9.6 percent GHG-free for all customers across its three products.
CleanPowerSF provides three electricity supply products for which separate Power Source Disclosure reports are required: (1) Green, (2) SuperGreen, and (3) SuperGreen Saver.
(1) Green
For calendar year 2024, CleanPowerSF’s Green product energy mix was 100 percent renewable resources:
• 88.4 percent California Renewable Portfolio Standard-eligible resources 49.8 percent solar
12.7 percent geothermal
22.4 percent wind
2.1 percent biomass & biogas
1.4 percent eligible hydroelectric
• 11.6 percent GHG-free hydroelectric generation
Staff estimates the Green product’s greenhouse gas intensity was approximately 3 pounds of CO2e/MWh of electricity delivered. By comparison, the statewide average for California in 2023 (latest available data) was approximately 373 pounds of CO2e/MWh.2
(2) SuperGreen
For calendar year 2024, CleanPowerSF’s SuperGreen product energy mix was 100 percent California Renewable Portfolio Standard-eligible resources:
• 50 percent solar
• 50 percent wind
All SuperGreen generation came from new renewable energy facilities built in California that either first reached commercial operation since CleanPowerSF began serving customers in 2016 or are located within San Francisco (Sunset Reservoir, which began operating in 2010). The greenhouse gas emissions intensity of the SuperGreen product was 0 pounds of CO
2e/MWh.
2 This number is an average of all load serving entities across California in 2023. This figure was included on the 2023 Power Content Label. The Power Content Label allows customers to easily compare the resource breakdown and emissions intensity of their electricity product with the State’s as a whole.
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(3) SuperGreen Saver
SuperGreen Saver is a product available for CleanPowerSF low-income customers3 who live in census tracks reported as within the top 25 percent of the most disadvantaged communities 4 in California. CleanPowerSF’s service territory includes 17 disadvantaged community census tracts.
Figure 1. Disadvantaged Community Census Tracts
*Customers living in the census tract on Treasure Island are entirely served by Hetch Hetchy Power, San Francisco’s municipal electric utility, and are therefore not part of CleanPowerSF’s service territory.
Image from CalEPA, accessed May 5, 2025 < https://oehha.ca.gov/calenviroscreen/sb535 >
For calendar year 2024, CleanPowerSF’s SuperGreen Saver energy mix was 100 percent California Renewable Portfolio Standard-eligible resources:
• 100 percent solar
SuperGreen Saver generation came from new (less than 15 years old) renewable energy facilit ies built in California and located in disadvantaged communities. The greenhouse gas emissions intensity of the SuperGreen Saver product was 0 pounds of CO2/MWh.
3 Low-income eligible customers must be eligible for and enrolled in either the California Alternate Rates for Energy Program (CARE) or Family Electric Rate Assistance Program (FERA). These programs provide monthly discounts on energy for income-qualified customers. 4 Disadvantaged communities are determined as such by the California Communities Environmental Health Screening Tool, developed by the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment. Commonly known as CalEnviroScreen, the tool is a screening methodology that can be used to identify California communities that are disproportionately burdened by multiple sources of pollution.
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Next Steps
Attestation of Veracity in September
After the SFPUC’s Power Enterprise and other retail sellers of electricity submit their Power Source Disclosure R eports, the California Energy Commission will compile the reports and calculate the statewide average greenhouse gas emissions intensity and use of energy resources by type. Power Enterprise staff will then develop the Hetch Hetchy Power and CleanPowerSF Power Content Labels that compare the results summarized here against the statewide average in 2024 . Power Enterprise staff will post the Power Content Label for each program on the SFPUC’s website. The California Energy Commission requires this to occur by October 1. Power Enterprise staff will also provide the Power Content Labels to our customers by mail by the end of the December billing cycle.
California Energy Commission regulations require that the SFPUC Commission attests to the veracity of both the Power Source Disclosure Report as well as the Power Content Label by October 1 of each calendar year. As the Power Content Label template will not be available by the June 2, 2025 Power Source Disclosure Report submission date, staff are providing this memo advising the Commission and the public of the sources of power for our two programs for calendar year 2024. Staff will bring two resolutions for the Commission’s approval that will attest to the veracity of the Hetch Hetchy Power and CleanPowerSF Power Source Disclosure reports and Power Content Labels, respectively, to a September 2025 Commission meeting.