Natural gas-fired reciprocating engines increasingly being deployed to balance renewables, EIA says

Published on February 21, 2019 by Kevin Randolph


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Reciprocating internal combustion engines are increasingly being used in larger utility-scale power generation applications, especially where large amounts of electricity generation from intermittent sources such as wind and solar are used, the U.S. Energy Information Administration (EIA) said recently.

Reciprocating internal combustion engines are typically used for backup, standby or emergency power. One of its primary advantages is the ability to provide incremental electricity quickly.

They can start up even if the grid has no power, which helps grid operators match fluctuating power requirements and restore power following major storms.

Power plants that have large reciprocating engines are often located in states with significant renewable resources, especially wind generation, EIA said.

Texas has the most wind electricity generation capacity in the country and 20 percent of the national total of natural gas-driven reciprocating engines. Kansas and California have the next highest capacities of reciprocating engines.


EIA noted that the advancement in engine technology that increases operational flexibility and changes in natural gas markets have also helped drive the increase in reciprocating internal combustion engine units. Engine manufacturers have also made improvement related to efficiency and emission reductions, especially emissions of nitrogen oxides (NOx). Power plants that use internal combustion engines also tend to need substantially less water than similarly sized combined-cycle or simple-cycle natural gas turbine plants.

Reciprocating engines are typically smaller than other types of natural gas-fired electricity generators. As of November 2018, the average reciprocating engine generator capacity was four megawatts (MW), compared to 56 MW for natural gas combustion turbines and 166 MW for combined-cycle units.

The size of reciprocating engines has increased in recent years, however. Before 2010, reciprocating engines typically had capacities of no more than nine MW. Recently, larger units ranging from 16 MW to 19 MW have been installed in the United States. Several of these engines are often installed at one generation facility.


Reciprocating engines also make up a relatively small percentage of power plants fueled by natural gas. According to data in EIA’s Preliminary Monthly Electric Generator Inventory, reciprocating engines accounted for one percent of the total natural gas-fired power fleet.