Conventional Energy

Our Approach

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 energy grid. When wind or solar production varies during the day, these facilities can ramp up quickly to meet customers’ electricity demand.

About the Facilities

PG&E continues the safe operation of our three natural gas-fired plants:

Colusa Generating Station: 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. The plant has 530 MW of base capacity and approximately 127 MW of low-cost peaking power that can be used at times when demand is high or in emergencies. ”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.
Gateway Generating Station: This 580-MW combined-cycle natural gas plant has 530 MW of base capacity and 50 MW of low-cost peaking capability. Like Colusa, the 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.
Humboldt Bay Generating Station: 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—selected for the region because of its flexibility and low emissions—uses reciprocating engines that are air-cooled, reducing water use by eliminating the need for ”once-through“ cooling from Humboldt Bay.

Measuring Progress

In 2021, PG&E’s natural gas power plants provided safe, reliable, and low-cost electricity to our customers. The following performance data represents the average availability factor of our natural gas power plants. The decrease in the plant availability factor was primarily due to additional planned outage durations during the year.

Natural Gas Power Plant Availability Factor ^{Footnote 1}
	2019	2020	2021
Gateway Generating Station	89.1%	91.3%	90.9%
Colusa Generating Station	92.5%	92.7%	81.7% ^{Footnote 2}
Humboldt Bay Generating Station	95.2%	89.3%	87.7%

1. Refers to the proportion of hours in a year that a plant is available to generate electricity.¹
2. In 2021, Colusa Generating Station underwent a planned major overhaul of the combustion turbines and unforeseen steam turbine generator challenges, resulting in a drop in its availability factor.²

Corporate Responsibility and Sustainability Report 2022