About the facilities
PG&E continues the safe operation of our three natural gas-fired plants:
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Renewable energy & storage
Other energy sources
Our approach
Along with our renewable energy portfolio, our hydroelectric, nuclear, and conventional systems jointly work to optimize the supply of clean energy to our customers.
Hydroelectric energy
PG&E’s hydroelectric system consists of nearly 100 reservoirs that feed 60 powerhouses and a pumped storage facility, for a total generating capacity of nearly 4,000 MW of clean power. Hydropower is a flexible, clean energy resource that helps the grid integrate intermittent sources of renewable energy such as wind and solar.
PG&E collaborates with water agencies, environmental organizations, and federal and state departments under the guidance of the Federal Energy Regulatory Commission (FERC) to balance hydropower generation with public recreation, water supply, and environmental protection―whether in times of drought or periods of extreme precipitation.
We also work together to repair and strengthen our hydroelectric infrastructure, manage wildfire risks, and mitigate environmental impacts. PG&E’s Dam Safety Program maintains the long-term safety and reliability of our water storage and water conveyance infrastructure and compliance with the regulations of the FERC and California’s Division of Safety of Dams.
We generated approximately 8.5 billion kWh
of carbon-free hydroelectric energy for our customers in 2023.
We stored nearly 1.3 GWh of clean energy
through the pumped storage process at our Helms Pumped Storage Plant.
We continued to enhance our Dam Safety Program
with a risk-informed approach and tools designed to improve the way our engineering teams conduct their dam inspections, surveillance, and monitoring.
Measuring progress
We gauge our hydroelectric performance in a number of ways: the reliability of our carbon-free hydroelectric power generation units; our progress on improving public safety around the flumes, canals, and other waterways we manage; and our compliance with environmental requirements for our operating licenses.
The following data represents the average availability factor of our hydropower facilities.
As part of PG&E’s wide-ranging public safety program, which includes K-8 education and an extensive dam safety and inspection program, we also track widening of berms along canals and the installation of fencing and gates to further protect the public around PG&E-managed waterways.
- In 2023 and 2024, our focus is on widening berms along canals; upon completion, we plan to install additional fencing in future years.
Nuclear energy
As directed by California Senate Bill 846, PG&E is taking actions to continue Diablo Canyon operations for five years beyond 2025 to support state electrical reliability needs. We stand ready to support the state’s goals to ensure statewide electric reliability and minimize greenhouse gas emissions, as California transitions to a clean energy future.
As the state’s single largest facility producing greenhouse gas-free electricity, Diablo Canyon is already helping the state reduce emissions and combat climate change. As a baseload generator of zero-emissions electricity 24/7, the plant provides enough energy to meet the needs of more than 3 million Californians and plays an important role in ensuring electric reliability for all Californians.
PG&E is committed to the highest levels of safety, performance, and security at Diablo Canyon. The Nuclear Regulatory Commission’s (NRC) latest annual assessment of the facility places Diablo Canyon among the highest-performing plants in the U.S. nuclear industry. This reflects the hard work and dedication of our coworkers and our commitment to meeting PG&E’s and the NRC’s high-performance standards.
Spent fuel storage
At both Diablo Canyon and PG&E’s former nuclear unit at the Humboldt Bay Power Plant, PG&E safely stores spent fuel in on-site dry container storage systems approved and licensed by the NRC. Diablo Canyon also safely and securely stores spent fuel in a wet storage facility. These two on-site interim storage solutions are federally monitored and follow industry best standards to ensure that they are safe and effective.
Water management
PG&E actively manages the water used in the nuclear generation process in accordance with the water discharge limit set by Diablo Canyon’s Clean Water Act permit.
Measuring progress
In 2023, Diablo Canyon Unit 1 underwent a safe and successful refueling outage. Units 1 and 2 produce 1,222 and 1,118 MW, respectively, of greenhouse gas-free electricity into the energy grid during regular operations.
Diablo Canyon continues to demonstrate high operational performance as gauged by its plant capacity factor, a measure of generation reliability. Diablo Canyon achieved a capacity factor of 90% during 2023.
- Refers to the ratio of the actual output of the plant relative to the output if the plant had operated at full capacity for the year.
PG&E continues to plan for the eventual decommissioning of Diablo Canyon while also maintaining safe plant operations and pursuing relicensing aligned with current state policy. Visit our website to learn more about the decommissioning planning process.
Conventional energy
PG&E operates three natural gas-fired power plants with best-in-class emissions levels and reduced water use via dry cooling:
- Colusa Generating Station
- Gateway Generating Station
- Humboldt Bay Generating Station
As flexible combined-cycle power plants, the Colusa and Gateway Generating Stations are an essential part of PG&E’s efforts to successfully integrate more renewable resources into the grid. When wind or solar production varies during the day, these facilities can ramp up quickly to meet customers’ demand.
This 657-MW combined-cycle natural gas plant features cleaner-burning turbines that allow the plant to use less fuel and emit significantly lower emissions than older plants. “Dry cooling” technology allows the facility to use 97% less water than plants with conventional once-through water cooling systems. The plant also uses a zero-liquid-discharge system that recycles wastewater and further reduces its water consumption.
Like Colusa, the 580-MW plant yields dramatically lower emissions for every megawatt-hour of power produced compared with older fossil-fueled plants. It also uses dry cooling technology, which minimizes water use.
This 163-MW natural gas plant is located in a relatively isolated section of California’s north coast region and provides a significant majority of the area’s electrical capacity. The plant’s design uses reciprocating engines that are air-cooled, reducing water use by eliminating the need for once-through cooling from Humboldt Bay.
Measuring progress
The following data represents the average availability factor of our natural gas power plants, which increased across the board in 2023.
- Refers to the proportion of hours in a year that a plant is available to generate electricity. In 2023, PG&E began reporting according to this methodology, which is more widely used by industry.
- In 2021 and 2022, Colusa Generating Station and Gateway Generation Station, respectively, underwent planned major overhauls of their combustion turbines, resulting in expected reductions in their availability factors.