The Chalk Point Generating Station is an

electricity-generating Electricity generation is the process of generating electric power from sources of primary energy. For utilities in the electric power industry, it is the stage prior to its delivery (transmission, distribution, etc.) to end users or its storag ...

plant, comprising oil and natural gas fired units, owned by

NRG Energy NRG Energy, Inc. is an American energy company, headquartered in Houston, Texas. It was formerly the wholesale arm of Northern States Power Company (NSP), which became Xcel Energy, but became independent in 2000. NRG Energy is involved in energ ...

, located near the town of

Eagle Harbor, Maryland Eagle Harbor is an incorporated town in the far southeast corner of Prince George's County, Maryland, Prince George's County, Maryland, United States, and near the rural community of Aquasco, Maryland, Aquasco that is known as a historic African Am ...

, United States, on the

Patuxent River The Patuxent River is a tributary of the Chesapeake Bay in the state of Maryland. There are three main river drainages for central Maryland: the Potomac River to the west passing through Washington, D.C., the Patapsco River to the northeast ...

. Plant operator

GenOn Energy Holdings GenOn Energy Holdings, formerly Mirant Corporation, was a subsidiary of GenOn Energy, and is now a part of NRG Energy. The company was spun off from its former parent, Southern Company, on April 2, 2001. The company was merged into GenOn Energy o ...

closed the two coal-fired units at the plant in June 2021. Environmental and community advocates supported the closure, but highlighted the lack of plan in Maryland to support a "

Just Transition Just transition is a framework developed by the trade union movement to encompass a range of social interventions needed to secure workers' rights and livelihoods when economies are shifting to sustainable production, primarily combating climat ...

" for the community and employees of the plant.

Individual Units

The facility consists of Units 3 and 4, which are oil and natural gas fired units rated at 659

MWe The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Watt ...

each, put into service in 1975 and 1981. These units are cooled by natural draft

cooling towers A cooling tower is a device that rejects waste heat to the atmosphere through the cooling of a coolant stream, usually a water stream to a lower temperature. Cooling towers may either use the evaporation of water to remove process heat and ...

. The units comprise seven

combustion turbine A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directio ...

s owned and operated by NRG. * Oil-fired units GT1 and GT2 (put into service in 1967 and 1974) are rated at 16 MWe and 35 MWe. * Oil/gas-fired units GT3–GT6 (put into service in 1991) are rated at 103, 103, 125, and 125 MWe respectively. * Unit SGT1, an oil/gas-fired combustion turbine, is rated at 94 MWe and was put into service in 1990. The turbine was owned by the

Southern Maryland Electric Cooperative The Southern Maryland Electric Cooperative (SMECO) is an electric distribution cooperative which is headquartered in Hughesville, Maryland, United States. SMECO serves approximately 161,000 customers in Calvert, Charles, Prince George's, and ...

(SMECO) until 2015, when it was acquired by NRG. The combined name-plate capacity of all seven combustion turbines is 601 MWe. Units ST1 and ST2, closed in 2021, are coal-fired dry-bottom, wall-fired steam generating plants rated at 364 MWe each. They were put into service in 1964 and 1965.

History

The Chalk Point plant began service in 1964.GenOn Energy, Houston, TX
"Chalk Point Generating Station."
Accessed 2011-06-28. All of the GenOn generating units at the Chalk Point Generating Station were built by the

Potomac Electric Power Company The Potomac Electric Power Company (PEPCO) is an American utility company that supplies electric power to the city of Washington, D.C. and to surrounding communities in Maryland. It is owned by Exelon. The company's current trademarked slogan i ...

, which sold them to the

Southern Company Southern Company is an American gas and electric utility holding company based in the southern United States. It is headquartered in Atlanta, Georgia, with executive offices also located in Birmingham, Alabama. The company is the second largest ...

in December 2000 as a result of the restructuring of the electricity generating industry in Maryland. The station was included in the

Mirant GenOn Energy Holdings, formerly Mirant Corporation, was a subsidiary of GenOn Energy, and is now a part of NRG Energy. The company was spun off from its former parent, Southern Company, on April 2, 2001. The company was merged into GenOn Energy o ...

spin-off from the Southern Company in April 2001. Mirant was merged into

GenOn Energy GenOn Energy, Inc., based in Houston, Texas, United States, was an energy company that provided electricity to wholesale customers in the United States. The company was one of the largest independent power producers in the nation with more than ...

in 2010, and GenOn merged into NRG in 2012. GenOn announced in August 2020 that it planned to shut down the two coal-fired units in June 2021. Environmental and community advocates supported the closure, but highlighted the lack of plan in Maryland to support a

for the community and employees of the plant.

Fuel delivery

Coal was delivered to the Chalk Point generating station by

CSX Transportation CSX Transportation , known colloquially as simply CSX, is a Class I freight railroad operating in the Eastern United States and the Canadian provinces of Ontario and Quebec. The railroad operates approximately 21,000 route miles () of track. ...

trains via the

Herbert Subdivision Herbert may refer to: People Individuals * Herbert (musician), a pseudonym of Matthew Herbert Name * Herbert (given name) * Herbert (surname) Places Antarctica * Herbert Mountains, Coats Land * Herbert Sound, Graham Land Australia * Herbert, ...

, a former

Pennsylvania Railroad The Pennsylvania Railroad (reporting mark PRR), legal name The Pennsylvania Railroad Company also known as the "Pennsy", was an American Class I railroad that was established in 1846 and headquartered in Philadelphia, Pennsylvania. It was named ...

(PRR) line. This line is accessed via the

Amtrak The National Railroad Passenger Corporation, Trade name, doing business as Amtrak () , is the national Passenger train, passenger railroad company of the United States. It operates inter-city rail service in 46 of the 48 contiguous United Stat ...

Northeast Corridor The Northeast Corridor (NEC) is an electrified railroad line in the Northeast megalopolis of the United States. Owned primarily by Amtrak, it runs from Boston through Providence, New Haven, Stamford, New York City, Philadelphia, Wilmington, a ...

line. The coal was delivered from trains staged at the CSX Benning Yard (also former PRR facilities) in Anacostia, Washington, DC.

Dispatch of electricity

The electrical output of Chalk Point Generating Station is dispatched by the

PJM Interconnection PJM Interconnection LLC (PJM) is a regional transmission organization (RTO) in the United States. It is part of the Eastern Interconnection grid operating an electric transmission system serving all or parts of Delaware, Illinois, Indiana, Kentu ...

regional transmission organization A regional transmission organization (RTO) in the United States is an electric power transmission system operator (TSO) that coordinates, controls, and monitors a multi-state electric grid. The transfer of electricity between states is considered i ...

Environmental impacts

In 2006 the U.S. Environmental Protection Agency (EPA) reported that the Chalk Point plant emitted over 21 lbs/MWh of

sulfur dioxide Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a toxic gas responsible for the odor of burnt matches. It is released naturally by volcanic activ ...

(SO₂), ranked as the 24th largest such emitter in the United States. It was ranked as the 43rd largest emitter of

nitrogen oxide Nitrogen oxide may refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds: Charge-neutral *Nitric oxide (NO), nitrogen(II) oxide, or nitrogen monoxide *Nitrogen dioxide (), nitrogen(IV) oxide * Nitrogen trioxide (), or n ...

s (). In 2010 EPA reported that Chalk Point emitted 4.7 metric tons of

carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...

(CO₂). In 2019 the plant emitted 0.6 metric tons of CO₂. In August 2018, the

Maryland Department of the Environment The Maryland Department of the Environment (MDE) is a government agency in the state of Maryland that implements and enforces environmental protection laws and programs. The agency's stated vision is "Healthy, vibrant and sustainable communities a ...

(MDE) required three generating stations across the state, including Chalk Point, to meet current federal wastewater standards (

effluent guidelines Effluent Guidelines (also referred to as Effluent Limitation Guidelines (ELGs)) are U.S. national standards for wastewater discharges to surface waters and publicly owned treatment works (POTW) (also called municipal sewage treatment plants). The Un ...

) by November 2020. The coal-fired units at these plants discharged

arsenic Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but ...

and

mercury Mercury commonly refers to: * Mercury (planet), the nearest planet to the Sun * Mercury (element), a metallic chemical element with the symbol Hg * Mercury (mythology), a Roman god Mercury or The Mercury may also refer to: Companies * Merc ...

to their respective receiving waters, as allowed by 1980s-era pollution standards under expired permits. Upgrading the plants' treatment systems to Maryland's current standards "could reduce discharges of toxic metals by 97 percent." EPA published the updated federal standards in 2015.

References