February 2022, Vol. 249, No. 2


Natural Gas-Fired Generators Used More in PJM Interconnection

Special to P&GJ 

The rapid development of shale gas resources in Pennsylvania, Ohio and West Virginia has contributed to sustained low natural gas prices, and it has encouraged the construction of natural gas-fired power plants.   

About one-third of the new natural gas-fired generating capacity built in the United States since 2010 is located in the PJM Interconnection (PJM), the grid operator for all or parts of 13 states in the mid-Atlantic region, including Pennsylvania, Ohio and West Virginia.   

In 2020, the utilization rate, called capacity factor, of natural gas-fired combined-cycle (NGCC) units built from 2010 to 2020 in PJM was 71%, which was higher than that of older units in the region, according to the U.S. Energy Information Administration (EIA).  

Two factors affect the utilization of a combined-cycle natural gas generator: the efficiency of the generator and the delivered cost of natural gas. Newer NGCC generators use more efficient turbine technology and are generally larger than older units.   

Although all NGCC generators tend to increase or decrease use in response to changes in the price of natural gas, older units tend not to be used when natural gas prices rise, because they are less efficient and more expensive to run than newer technology units.  

EIA separates combined-cycle natural gas turbines in PJM into three groups, which reflect the turbine technologies available at the time they were built:  

Units built from 1990 to 1999 – B-, D-, and E-class gas turbines (GT) with 80 MW to 110 MW capacity and average heat rates greater than 8,000 Btu per kilowatt hour (Btu/kWh) in combined-cycle mode  

Units built from 2000 to 2009 – First-generation F-class GTs with 160 MW to 190 MW capacity and average heat rates of 7,300 Btu/kWh in combined-cycle mode  

Units built from 2010 to 2020 – Next-generation F-class GTs with 200 MW to 225 MW capacity and average heat rates of 7,000 Btu/kWh in combined-cycle mode, first-generation advanced H- and J-class GTs with 265 MW to 340 MW capacity and 6,700 Btu/kWh heat rates in combined-cycle mode  

Grid operators, such as PJM, dispatch generators sequentially from lowest to highest cost. Because NGCC units built from 2010 to 2020 generally have the lowest operating costs, these are dispatched more frequently.   

Because of their lower efficiency, units built from 1990 to 1999 have higher operating costs and are more likely to be the marginal generators in the dispatch order, meaning they are the last combined-cycle generators to be dispatched. 

Power generation from natural gas in the region should during the next few years, especially in Pennsylvania, according to the state Public Utility Commission (PUC). The PUC’s “Electric Power Outlook for Pennsylvania 2018-2023” report anticipates gas-fired power generation makes up about 45% of the state’s installed capacity, a significant increase. 

An earlier  U.S. Energy Information Administration (EIA) report said 17 new natural gas-fired plants will be in various stages of development from this year through 2022, with those facilities representing about 8.5 GW of generation capacity. 

In Ohio, Bechtel completed engineering, procurement and construction (EPC) work at a new $1.3 billion combined cycle gas turbine plant in Ohio during the fourth quarter of 2021. The 1,182-MW South Field power plant is the second CCGT plant that Bechtel has completed for Advanced Power in the state. 

The South Field Energy project in Columbiana County is now in commercial operation. The project is largely owned by Advanced Power and an investor group including several Japanese firms. The EPC work was completed in 37 months. 

In West Virginia, the state Department of Environmental Protect recently approved a construction permit for the natural gas-fired expansion at the Mountain State Clean Energy, LLC facility in northern Monongalia County. 

Currently, the facility is a 700 megawatt coal-fired plant that employs 150 full-time workers. The power produced at the current facility is distributed through PJM Interconnection across a 13-state region serving 65 million people. 

The expansion includes two natural gas-fired turbines that will add 1270 megawatts of capacity and tap the Marcellus natural gas reserve. The project is valued at $1.1 billion and is expected to be in operation in 2024.  

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