At a Crossroads: Hydropower in California
By: 2024 National PT/MT Fellow Samantha Dadok
As California races toward a clean energy future, hydropower finds itself at the center of a heated debate. Long celebrated for its ability to provide renewable and reliable energy, it faces long overdue scrutiny as communities grapple with the ecological and cultural costs of the aging infrastructure.
Hydropower undeniably remains a crucial component of California’s energy grid, offering grid stability as the state transitions to a future powered by variable renewables like wind and solar. However, the time has come to quickly and critically re-evaluate this energy source and modernize its role to ensure it supports ecological restoration and respects the cultural significance of waterways.
The Origins of Hydropower in California
Hydro projects, and by extension, hydropower, have been a hallmark of California’s economic development since the state’s inception. They have redrawn the boundaries of “livable” spaces within the state, at significant cost to the native ecosystem and communities who did not win the so-called water wars of the early 1900’s. It is well known that urban hubs such as Los Angeles wouldn’t exist without the massive reengineering effort to deliver water (and power) through the Owens Valley Water Project. While Hetch Hetchy is more well known for supplying drinking and irrigation water to the Bay Area, 20% of San Francisco’s electricity comes from it as well. In fact, this is mirrored with the rest of the state in “wet” years, when up to one-fifth of CA’s electricity supply can come from hydropower. Though its generation capabilities are drastically cut in the event of drought, recent studies show that climate change will cause an increase in hydropower generation potential in almost every region of the US in the next 30 years. Moreover, despite advances in battery technology, pumped hydro still accounts for 98% of California’s installed energy storage today, allowing excess solar and wind energy to be stored and used instead of being curtailed.
The Case for Hydropower’s Continued Role
Hydropower will, and should, continue to play an important role in California’s energy grid, especially for grid stability as we transition to renewables. Hydroelectric power, being renewable itself, is also a critical enabler for our broader transition from carbon intensive electricity sources to variable solar and wind generation. Hydropower can be quickly ramped up or down, providing grid balancing services that intermittent sources like solar and wind cannot deliver as consistently today. Pumped storage hydropower is and will remain a valuable form of large-scale energy storage in California, helping to offset periods when solar or wind are not producing. With costs declining for installed capacity of lithium ion battery (LIB) storage to record lows at $139/kWh and installations ramping quickly in the state, one might think LIB is the panacea to our energy storage problems. They indeed will be a critical flexible resource to power CA’s energy transition. Even so, with individual pumped hydro plants able to surpass 1 gigawatt in capacity — a level not yet achieved in utility scale battery projects — pumped hydro can address large-scale grid imbalances and provide black-start capability even in the event of a major grid failure.
Re-Evaluating the Role of Hydropower
California’s hydro projects reshaped the state and left undeniable economic, cultural and ecological transformations. While some regions, like Los Angeles and the San Fernando Valley have boomed, others have languished. Dam construction has not only led to the forced displacement of Indigenous communities from their ancestral lands across the U.S., but also disrupted the cultural and spiritual connections many tribes hold with natural rivers. Salmon populations in sensitive tributaries like the Klamath have been decimated in fish kills linked to excessive water diversions for agriculture, and it is predicted many native California fish species will disappear from the state within the next century if present trends on water consumption and diversion continue. Water quality downstream can be degraded by artificially increasing river temperatures and risking toxic algae blooms, such as in the case of the Klamath River Dams.
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Much of this infrastructure, on average built over 70 years ago, has deteriorated. With recent federal legislation targeting aging infrastructure and the growing risks climate change poses to dam safety and functionality, California faces a pivotal opportunity to reimagine hydropower. By removing outdated structures that no longer serve a significant purpose, we can prioritize ecological restoration, while refurbishing essential dams with advanced technologies to reduce their impact on surrounding communities.
What’s Next for Hydropower in California
California stands at a pivotal moment for the health of its rivers, communities, and overall well-being. We have a unique opportunity to reverse the damage caused by past planning and construction while acknowledging hydropower’s role in the state’s clean energy future.
- Aggressively Re-evaluate Existing Hydropower Operations: A statewide assessment of dams should be taken to determine which remain critical for energy reliability versus those that could be modified or removed to restore ecosystems. Dams that are critical for other reasons (irrigation, water storage, flood control) should be retrofitted for hydropower generation where possible to provide further renewable generation and avoid building new dams. Small-scale run-of-the-river development such as dam-toe should be heavily prioritized over medium-large projects to capture renewable energy of free-flowing water without using impoundment, minimizing impact of development on the river system structure and ecology.
- Bring CA Hydropower into the 21st Century: Refurbish aging hydro projects with fish friendly tech, such as ladders and fish safe turbines to restore spawning grounds. Invest in research of freshwater mollusk migration. Enhance water release management for ecological health to ensure artificially high temperatures do not persist downstream and continue research funding for innovative methods to reduce toxic algae blooms in existing reservoirs such as floating solar installations on reservoirs.
- Build Collaborative Decision-Making Processes: As aging hydropower structures face re-permitting or refurbishment, it is essential to involve environmental experts, Indigenous leaders, and other stakeholders in the decision-making process to ensure that ecological health and cultural ties to water sources are respected and prioritized.
As we face an era of rapidly changing climate, hydropower must continue to play a role in California’s clean energy transformation and grid stability. Balancing those real benefits with cultural and ecological responsibilities is essential. We must remove outdated structures where we can, and invest in inclusive planning practices and emerging technologies to mitigate its negative impacts.
About the author
Samantha Dadok is a strategy consultant with a passion for advancing energy justice through intersectional approaches.
