PG&E to Study Mokelumne Water Temperatures Before Seeking Pumped Storage License

CSPA and the Foothill Conservancy have signed an agreement with Pacific Gas & Electric Co. that requires PG&E to model water temperatures in the Mokelumne River. PG&E must perform the modeling before it seeks a license to construct a pumped storage hydroelectric project in the watershed. The agreement arose after CSPA and Foothill Conservancy became parties to a proceeding at the Public Utilities Commission. In the proceeding, PG&E seeks authorization to charge $38,000,000 to ratepayers in order to pay for feasibility studies and a licensing proceeding before the Federal Energy Regulatory Commission.

The proposed pumped storage project would pump water from Salt Springs Reservoir to Lower Bear Reservoir during the night, and release the water through a powerhouse back to Salt Springs during the day. PG&E seeks to construct the facility for its ability to store wind-generated electric power, which is sporadic in timing. Wind energy often peaks at night when demand is low. Pumped storage serves as a battery to shape wind energy for use as it is needed on the electric grid.

CSPA does not oppose pumped storage per se, and recognizes the need to shape renewable energy sources. However, CSPA opposes pumped storage that is badly sited and that has adverse impacts on rivers and fish. For several years, CSPA and Foothill Conservancy have expressed skepticism that the proposed Mokelumne River pumped storage project can be built without significantly warming water temperatures in the river, perhaps even downstream of Camanche Dam.

According to the agreement, PG&E will model water temperatures downstream as far as Electra Powerhouse as part of its feasibility analysis, before beginning a formal licensing proceeding. If temperature impacts are shown, PG&E will extend its feasibility modeling further downstream, including the Electra and Middle Bar reaches, and Pardee and Camanche reservoirs. Preliminary discussions have indicated the cooperation and concern of East Bay MUD, which operates Pardee and Camanche.

CSPA and Foothill Conservancy were concerned that a large investment would be made without up-front focus on a likely fatal flaw. Should our concerns bear out, we may have saved PG&E ratepayers over $30,000,000 by sequencing studies appropriately. PG&E eventually saw the wisdom of our approach.

Counsel for the California Hydropower Reform Coalition, Richard Roos-Collins, represented Foothill Conservancy and CSPA in this matter.

In exchange for agreement on temperature modeling, CSPA and Foothill Conservancy agreed not to oppose cost recovery by PG&E.

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