What Is a Peaker Plant?

A peaker plant, also known as a peaking power plant, is a power generation facility that operates only during periods of high electricity demand. Unlike baseload plants that run continuously, peaker plants might operate only a few hundred hours per year, firing up when demand spikes during hot summer afternoons, cold winter mornings, or when other generators experience unplanned outages.

Most peaker plants in the United States are fueled by natural gas and use simple-cycle combustion turbines, essentially jet engines adapted to generate electricity. These turbines can start up in 10 to 30 minutes and reach full output quickly, making them well-suited to respond to rapid changes in demand. By contrast, large steam-cycle power plants may require hours to reach operating temperature.

Why Peakers Exist

The economics of electricity generation create a natural division between baseload and peaking resources. Baseload plants like nuclear, coal, and combined-cycle natural gas have high capital costs but low operating costs, making them efficient to run continuously. Peaker plants have lower capital costs but higher operating costs per unit of electricity because simple-cycle turbines are less fuel-efficient than combined-cycle plants.

This cost structure means peakers only make economic sense when electricity prices are high enough to cover their higher operating costs, which happens during peak demand periods. A peaker plant might lose money running at wholesale prices of $30 per megawatt-hour but profit handsomely when prices spike to $200 or $500 during a heat wave. Capacity market payments and reliability contracts provide additional revenue to cover the fixed costs of maintaining plants that sit idle most of the year.

Environmental and Community Impact

Peaker plants have outsized environmental and health impacts relative to their electricity contribution. Because they use less efficient simple-cycle turbines, they produce more emissions per megawatt-hour than baseload gas plants. Many peaker plants are located in urban areas and lower-income communities where land was available and permitting was easier decades ago when the plants were built.

These plants emit nitrogen oxides, particulate matter, and other pollutants that contribute to respiratory illness. Environmental justice advocates have long targeted peaker plants for retirement, arguing that the health burden falls disproportionately on communities that benefit least from the electricity produced.

The Battery Challenge to Peakers

Grid-scale battery storage is increasingly competitive with natural gas peakers for short-duration applications. A four-hour battery can fulfill the same peak-shaving function as a peaker plant, dispatching stored energy during the hours of highest demand. Batteries respond faster than turbines, produce no emissions, and can be sited anywhere on the grid.

The economics have crossed over in many markets. In California, New York, and Texas, new battery installations are undercutting the cost of both new and existing peaker plants. Several utilities have announced plans to replace aging peaker plants with battery storage, citing both cost savings and emissions reductions. New York City’s plan to phase out peaker plants in favor of battery storage and demand response has become a model for other urban areas.

What Comes After Peakers

The transition from natural gas peakers to batteries is well underway, but it is not complete. Batteries are currently limited to four to six hours of duration, which is sufficient for daily peak shaving but not for extended multi-day weather events when demand remains elevated for days. Longer-duration storage technologies and firm dispatchable generation will be needed to fully replace the reliability role of peaker plants.

In the near term, the most likely outcome is a hybrid approach where batteries handle daily peak management and aging peaker plants are retained for emergency backup during extended extreme weather events, running even less frequently than they do today. Over the next decade, as storage duration increases and costs decline, the case for new natural gas peakers will likely disappear entirely.