About the Business

Conventional Power Sources



Total generating capacity of three state-of-the-art natural gas-fired power plants owned by PG&E with best-in-class emissions levels

PG&E continues to build a diverse portfolio of generation resources to ensure adequate supplies of energy for our customers. This includes making long-term investments in cleaner conventional generation that, under specific state requirements, must meet a stringent greenhouse gas emissions performance standard equivalent to an efficient, combined-cycle natural gas plant. Investing in highly efficient and flexible natural gas-fueled plants is also critical as we increase the amount of renewable energy in our power portfolio, because it provides the operational flexibility needed to back up intermittent renewable resources, such as solar and wind energy.

Conventional Generation Owned and Operated by PG&E

Prior to 1999, PG&E owned more than 7,000 MW of oil- and gas-fired conventional boilers and combustion turbine generating facilities. In the late 1990s, in response to California’s electric generation deregulation law, PG&E sold all but two of its fossil-fueled power plants, Hunters Point Power Plant and Humboldt Bay Power Plant. PG&E has since retired these two plants and replaced the Humboldt Bay Power Plant with a new cleaner, high-performance plant at the same site.

Since early 2009, PG&E has safely commissioned three state-of-the-art natural gas-fired plants with emissions levels that are best in class:

The Humboldt Bay Generating Station

Humboldt Bay Generating Station

The Colusa Generating Station

Colusa Generating Station

The Gateway Generating Station

Gateway Generating Station

  • Humboldt Bay Generating Station: This 163 MW natural gas plant is 30 percent more efficient than the older fossil-fueled plant it replaced. It employs technology that emits significantly less SO2, NOX and CO2 than the previous facility.

    The plant is located in a relatively isolated section of California’s north coast region and provides a significant majority of electrical capacity to the area. The plant’s design—selected for the region because of its low emissions and flexibility—uses reciprocating engines that are air-cooled, reducing water use by eliminating the need for once-through cooling from Humboldt Bay.
  • 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 less CO2 than older plants. “Dry cooling” technology allows the facility to use 97 percent less water than plants with conventional “once-through” water cooling systems.

    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 emergency situations. In addition, the plant is designed to lower its power output when renewable resources like wind and solar become available. The plant uses a zero liquid discharge system that recycles waste water 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. On average, the plant yields dramatically less NOX, SO2 and CO2 for every megawatt-hour of power produced compared to older fossil-fueled plants. Gateway also uses dry cooling technology.

New Plant Under Contract

Recognizing that intermittent renewable resources like wind and solar need flexible capacity to fill in gaps in energy supply, last year the CPUC approved an agreement between PG&E and Contra Costa Generating Station LLC to add another new natural gas fueled facility in Oakley, California.

The 586 MW combined-cycle natural gas facility is designed to feature newer combustion turbine technology, which provides highly efficient peaking, load-following and quick-start capabilities that would allow PG&E to better balance intermittent renewables. The plant is designed to emit 35 percent less CO2 for every megawatt hour of power produced than other types of fossil-fueled alternatives, and is planned to be built on an existing industrial site, further minimizing environmental impact. Like all of PG&E’s natural gas plants, Oakley would also be air-cooled.

Contra Costa Generating Station LLC has agreed to construct and sell the plant to PG&E, with the goal of becoming operational in 2016. It is estimated that construction of the power plant would create more than 700 jobs and bring millions of dollars into the local economy. At peak operation, Oakley would produce enough electricity for about 500,000 homes, enhancing PG&E’s ability to deliver safe, reliable and affordable energy to customers.