U.S. Energy Information Administration – EIA

April 25, 2022


Pure gas is the most prevalent electricity supply employed for electrical energy technology in the United States. Of the 491 gigawatts (GW) of natural gas-fired electric powered-producing capability in the country, additional than 50 % (280 GW) are merged-cycle programs that contain each steam turbines and combustion turbines. The predominant configuration for combined-cycle units consists of two combustion turbines and one particular steam turbine (2×1).

Natural gasoline-fired electrical electric power crops use both basic-cycle or put together-cycle power conversion. Easy-cycle devices consume organic fuel in a one conversion method, this kind of as a combustion turbine, boiler with a steam turbine, or internal combustion motor. In these methods, vitality from the primary conversion exhaust warmth is lost and not despatched to an additional turbine. Blended-cycle techniques send out combustion turbine exhaust heat to a warmth restoration steam generator, pressurizing steam for just one or much more steam turbines that generate supplemental electrical ability.

Blended-cycle techniques have a tendency to be more productive at changing a device of normal gasoline (measured in British thermal models [Btu]) to a device of electrical power (kilowatthour [kWh]). Put together-cycle programs have an normal operating warmth amount of 7,146 Btu/kWh compared with very simple-cycle techniques, which consume about 10,000 Btu to create 1 kWh, dependent on 2020 averages. Mainly because of the performance gains, combined-cycle devices usually operate at larger capability factors than simple-cycle devices. As a result, mixed-cycle techniques usually provide base and intermediate hundreds to the grid, even though basic-cycle systems typically serve peak load.

In our Electrical Electricity Yearly survey, we gather a device code identifier to team put together-cycle factors into energy blocks. Power block configurations fluctuate commonly, which include configurations these kinds of as multiple combustion turbines supporting a single or more steam turbines. Most mixed-cycle ability blocks have combustion and steam turbine components each individual linked with a generator. Nonetheless, 13 GW of combined-cycle capacity are one-shaft devices in which both of those the combustion and steam turbines travel a widespread generator on 1 shaft.

In phrases of producing potential, the most significant pure gasoline mixed-cycle power plant in the United States is Florida Electricity & Light’s West County Power Middle. The West County Power Centre consists of a few 3×1 electrical power blocks, or a total of 12 combustion and steam turbines. Just about every of the 3 electricity blocks is rated at 1,259 megawatts (MW), offering the plant 3,777 MW of total producing ability. The West County Electricity Centre produced 20.3 terawatthours of electrical power in 2021 only 5 nuclear power vegetation and a single coal-fired plant produced additional electrical energy very last year.

average natural gas combined-cycle power block capacities

&#13
Source: U.S. Strength Info Administration, Electric powered Electricity Yearly
Observe: Energy blocks are classified by the initial working year of the most just lately built component.&#13

Put together-cycle electrical power blocks have enhanced in ordinary capability since 2015, when a new course of combustion turbines grew to become much more common. These more recent combustion turbines make it possible for mixed-cycle electricity blocks to have bigger capacities and enhanced efficiencies. The typical capacity of a 2×1 ability block amplified from 500 MW for those people created just before 2015 to about 700 MW for individuals constructed right after 2015.

Principal contributors: Ray Chen, Mark Morey