Hydropower: "renewable" under the law? Pumped storage at Rock Creek?

A couple of proposals involving hydropower are afoot.

The first involves California's Renewable Portfolio Standard" (RPS). First adopted in 2002, the RPS is part of California's effort to be a leader in combating climate change and is intended to give utilities the incentive to invest in solar, wind and geothermal power. The RPS has been modified several times since first adopted in 2002. Currently the RPS calls for 60% of electricity production to be renewable by 2030 and 100% to be renewable by 2045.

But what about nuclear power and hydropower? Where do they fit within the RPS? As always, the devil is in the details.

Nuclear has become a non-issue as California's last operation nuclear plant, Diablo Canyon, is expected to close in 2025 (Humboldt 3 closed in 1976, Rancho Seco closed in 1989 and San Onofre closed in 2013.)

Hydropower is a different story. In California, hydropower counts for 15-50% of total generation in most years. When the RPS was adopted, a political compromise decided that plants under 30 megawatts would count as renewable and those over 30 megawatts would not count as renewable.

So San Francisco's three facilities in the Tuolumne watershed (Kirkwood, Holm and Mocassin) are not presently considered renewable under the law. Nor is Don Pedro, downstream on the Tuolumne and operated by the Turlock and Modesto Irrigation Districts.




Hydropower on the Tuolumne

San Francisco's Kirkwood, Holm and Moccasin plants will still be operational when Hetch Hetchy is restored - total production will decline by about 20%



Turlock and Modesto are leading an effort to change the law, so all hydropower would be counted as "renewable". Not surprisingly, the Modesto Bee is in support. An editorial opinion in the Los Angeles Times explains the proposal would undermine California's clean energy mandate.

If hydropower were declared renewable and there were no other changes in the RPS regulations, investments in solar, wind and geothermal would be diminished. In theory it would be possible to change the RPS targets so the intended investments would be unchanged. Politics being what it is, however, it seems likely that the proposed legislation would lessen California's effort to do its part to combat global warming.

The discussion above does not really address the impacts that hydropower does have on rivers, fisheries and other wildlife. California's largest dams were built primarily for water supply - with flood control and hydropower as important side benefits. San Francisco's plants fit this category. If the dams and diversions must be in place, harvesting the energy from hydropower is indeed a good thing. But Restore Hetch Hetchy would much prefer that San Francisco's Hetch Hetchy hydropower not be considered renewable under State law.

The second hydropower proposal in the news is to build a pumped storage facility on Rock Creek in the eastern Sierra Pumped storage acts like a battery. Water is pumped uphill when surplus/cheap power is available, then released to generate power when it is needed. Typically these plants are about 70% efficient.




Heart Lake

Upper Rock Creek watershed - eastern Sierra



Decades ago, pumped storage was developed to complement inflexible nuclear plants. PG&E and SCE have major pumped storage facilities in the southern Sierra, on the Sierra's west slope. Today, some are calling for more pumped storage to complement the intermittent power produced by wind and solar.

At Restore Hetch Hetchy, we think the magnificent high Sierra has suffered enough from development and we should do everything we can to avoid further destruction of our granite wonderland.

And some of that destruction should be undone, starting with returning Hetch Hetchy Valley in Yosemite National Park to its natural splendor.