Potomac River Generating Station (formerly GenOn)

NRG owns the Potomac River Generating Station (formerly GenOn) in the City of Alexandria. Once one of the largest industrial facilities in the city, it was decommissioned in 2012. The site currently undergoing remediation. The Virginia Department of Environmental Quality has primary regulatory authority for site cleanup.

Page updated on Jul 29, 2021 at 4:49 PM

June 2020 Project Summary of NRG Potomac River Generating Station (PRGS) Site Remediation and Groundwater Monitoring Work  

The NRG’s former power plant at the Potomac River Generating Station (PRGS) site was permanently closed in October of 2012 under an agreement with the City following years of litigation. As part of the de-activation of this plant, NRG filled the two underground oil storage tanks (USTs) at this site with lightweight flowable fill (February 2013). City Code Administration staff was on site to inspect. Soil and ground water sampling around these tanks were also carried out. Based on the sampling results, the Virginia Department of Environmental Quality (VDEQ) decided to open a pollution complaint case and requested that NRG perform a full site characterization (March 2013).

The initial Site Characterization Report (SCR) submitted by NRG was deemed insufficient by VDEQ and an addendum having further characterization testing was then required by this agency. The Site Characterization Report Addendum (SCRA) was finally submitted to the VDEQ in February of 2014. Its findings can be summarized as follows:

  • The release of heating oil from the two heating oil USTs covers an area of 16,000 square feet.
  • The large mass of petroleum hydrocarbons present beneath the power station poses a significant risk of ongoing releases of petroleum contaminants to the Potomac River.

VDEQ reviewed this SCRA and required a Corrective Action Plan (CAP) for this site. NRG carried out further characterization work in developing the CAP and submitted the proposed CAP to VDEQ in December 2014. The total petroleum hydrocarbons mass present in the vicinity of these USTs is estimated by NRG to be ~17,400 gallons. Feasibility testing of several remediation technologies was presented and most feasible remedial strategies were proposed. The proposed remedial activities were estimated by NRG to be completed by 2019 at an estimated cost of ~ $1 million. The Corrective Action Plan was approved by VDEQ in March 2015 following a public meeting in Alexandria.

National Park Service (NPS) administers two parcels of land totaling 3.25 acres between the PRGS site and the Potomac River. Based on information provided to it by the District Department of Environment and Energy (DDOEE) indicating potential contamination of these land parcels, NPS made a formal request to the Virginia Department of Environmental Quality (VDEQ) to include this land in any regulatory sampling requirements for the NRG site.

In June of 2014, the DDOEE issued a Compliance Directive to NRG Energy following its review of the SCRA. The purpose of this Compliance Directive is to further investigate the extent which the Potomac River and its sediments have been impacted by the fuel-oil contaminated groundwater coming from the PRGS facility. NRG is required to develop 1) a work plan to investigate the extent of groundwater contamination along the Potomac River shoreline; and 2) a work plan for a complete evaluation of the bulkhead adjacent to the PRGS Pump House.

By April 2016, the remedial technologies (Pump & Treat, Total Phase Extraction and Biosparge) outlined in the CAP have been installed and in operating mode. To complete the entire remediation requirements of the Corrective Action Plan, along with separate directives from the DDOEE (Work Plan, approved 11-2-15), NRG also installed and connected an additional seven biosparge points to the remediation system and to seal the seeps along the bulkhead wall along the Potomac River. The DDOEE activities also included the addition of fourteen additional groundwater monitoring points near the river.

From April 2016 to present, NRG/GenOn has regularly sent quarterly reports to the VDEQ and DDOEE to document progress and technical challenges. In its latest Quarterly CAP Implementation Monitoring Report submitted to the VDEQ dated April 28, 2020, GenOn/NRG reported that “the remedial system was turned off on September 29, 2019. Based on groundwater concentrations measured during the first quarter 2020, the system will remain off at this time. Post-remedial monitoring will proceed for a minimum of six additional quarters. In the past six months since the system shutdown, no measurable LNAPL (light non-aqueous phase liquid) has been detected”. Following a total of eight quarters of monitoring, and pending favorable trend of groundwater contaminant concentrations, GenOn is proposing to submit a final report and request for case closure to the VDEQ. If VDEQ concurred with this assessment, this would be the completion of the remediation work under the VDEQ’s directives. 

Concurrently, GenOn has also continued to report to the DDOEE on its remedial activities under the DDOEE’s directive, with the latest report being issued on April 30, 2020. Regarding the recent $2.5 million settlement between DDOEE and GenOn Holdings, it appears that while the case was a result of the underground tanks leaking, it did not have anything to do with the current activities on-site. These were all historic discharges prior to the outfalls being sealed.  

Virginia DEQ Approves NRG's Proposed Corrective Action Plan for Remediation at the PRGS Site

The Virginia Department of Environmental Quality (VDEQ) has completed its review  of NRG’s proposed Corrective Action Plan (CAP) dated December 23, 2014. VDEQ granted approval of this CAP since the proposed remediation strategies were found to comply with VDEQ’s requirements. In its letter to NRG dated March 17, 2015, VDEQ specified the 7 additional requirements and clarifications for its approval, including requirements for NRG to work with the City, National Park Service and the District  Department of Environment to ensure that the objectives of the City and these regulatory stakeholders are met satisfactorily.

City's Comment Letter on the NRG's Proposed Corrective Action Plan for Remediation at the PRGS Site

Virginia Department of Environmental Quality (VDEQ) to hold public Meeting on NRG's Proposed Corrective Action Plan (CAP) for Remediation at the PRGS Site on February 3, 2015

  • As required by VDEQ, a public meeting will be held by VDEQ and NRG Energy on Tuesday, February 3 to obtain public comments regarding the NRG Energy's CAP recently submitted to VDEQ.  The proposed CAP outlines remediation for two leaking 25,000-gallon heating oil tanks located underground at the PRGS site. Following this meeting, the public can submit comments  to VDEQ by February 13, 2015. 

    Date:   February 3, 2015
    Time:   7- 9 p.m.
    Location:  City Hall, Sister Cities Conference Room #1101

    For more information, please contact Khoa Tran, T&ES Infrastructure and Environmental Quality, 703.746.4076.

First Meeting of the PRGS (Potomac River Generating Station) Monitoring Group

Following the permanent closure of the GenOn PRGS power plant, City Council adopted a resolution in December 2012 establishing the PRGS Monitoring Group and reappointing the current membership of the recently-expired Mirant Community Monitoring Group (MCMG) as members of the PRGS Monitoring Group for a period of two years or until the substantial completion of the NRG PRGS deactivation/ decommissioning phase, whichever happens first.

The first meeting of this group is to be held on March 5, 2013 at 7:30 pm to 8:30 pm in the City Council Work Room at City Hall. The agenda is attached here .

GenOn and NRG Officially Merged on December 14, 2012

The name of the new company is NRG Energy, Inc.. Information about NRG and the merger can be found on NRG website www.nrgenergy.com.

 Going forward, NRG contacts regarding the Potomac River Generating Station are as follows:

GenOn and Virginia DEQ (VDEQ) Mutually Determined that PRGS Was Shut Down Permanently as of December 21, 2012

The VDEQ issued a letter to GenOn Energy on December 20, 2012 to confirm that following a PRGS facility inspection by the VDEQ which City staff also participated in, GenOn and the VDEQ mutually determined that the GenOn PRGS power plant has been shut down permanently as of December 21, 2012. Consequently, the following will apply:

1. The air permits issued for the PRGS dated July 31, 2008 and July 29, 2010, are revoked.

2. The revocation of these permits shall not relieve GenOn or its successors of the responsibility to comply with all applicable local, state, and federal statutes or regulations with regard to the PRGS.

3. The PRGS shall cease operations as an electric generating facility. No such future operations shall occur until the owner has obtained a permit pursuant to the Virginia Regulations (9 VAC 5 Chapter 80).

Please click here to see the full details of the letter. 

GenOn Presentation on PRGS Phase I Deactivation Plan

Misty Allen, Vice President Asset Management of GenOn Energy - Eastern PJM Region, presented the Phase I Deactivation Plan currently being implemented at the company's Potomac River Generating Station (PRGS) at the Mirant Community Monitoring Group (MCMG) meeting on November 7, 2012.  Please click here for an electronic copy of her presentation. For updates on this deactivation plan, please check information on the following GenOn PRGS website:  http://www.genon.com/company/stations/potomac/new-and-events.aspx

City Recognizes Closure of GenOn Potomac River Generating Station

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Alexandria Significantly Improves Air Quality and Protects Public Health with Power Plant Closure

Monday, October 1, 2012, marked a significant milestone for the City of Alexandria and its residents with the permanent closure of the GenOn Potomac River Generating Station (PRGS). For several years this facility has been the single largest source of air pollutants in Northern Virginia. Its closure is a culmination of intense and unwavering efforts by the residents and the City Government for more than a decade. From the City's perspective, operation of the PRGS had been a serious public health issue. In response to citizens' concern, the City Council adopted a resolution in 2004 stating the City's policy to clean up PRGS in the short term and close it down permanently in the long term.

The City then participated in the State regulatory process which resulted in the issuance of a comprehensive permit for this plant in 2008 having tight emission limits that conform to all National Ambient Air Quality Standards. The same year, the City and GenOn also reached a Settlement Agreement requiring GenOn to spend $34 million on improved stack gas and fugitive fine particulate matter controls in addition to the $35 million the company spent on its stack merge project aimed at mitigating air quality issues in the plant vicinity. Subsequently and before the City and GenOn committed to installing the improved baghouse technology at this facility, the two parties reached an agreement on August 29, 2011 to permanently close the company's PRGS facility by October 1, 2012, in exchange for the return of about $32 million to the company.

This plant closure is consistent with the Eco-City Alexandria's Environmental Action Plan and benefits both Alexandria residents and those living in the Washington Metropolitan areas. An additional benefit is the drastic reduction in the emissions of greenhouse gas which is believed to be the major contributor to the current climate change issue.

"This plant closure is a testament to the City's commitment to environmental stewardship, public health protection, and the Eco-City Alexandria initiative" said Alexandria´s Mayor William D. Euille.

For a timeline of key milestones in the Alexandria community efforts to close down PRGS, please click here .

On September 27, 2012, GenOn notified the Virginia Department of Environmental Quality (VDEQ) that it will no longer operate any of the coal-fired boilers or generate electricity at the Potomac River Generating Station as of 00:00 on October 1, 2012. GenOn will work with VDEQ in making a mutual determination that PRGS is permanently shut down on or before December 31, 2012. As a result of this determination, all air permits issued to PRGS by VDEQ will be revoked. Click here for a copy of the GenOn letter.

About GenOn Potomac River Generating Station

The purpose of this web page is to provide the interested citizens the most updated information regarding Council's Actions, Staff's Actions, Actions taken by regulatory authorities and other relevant information of interest. The website is divided into several categories as indicated by the various links on the left side. New and updated information will be posted periodically as it becomes available. Announcements of upcoming meetings will also be posted on this website. Please click on the links below or to the left to access the most recent information available.

News Archive

  • GenOn Announces Its Intent to Merge with NRG
    On July 22, 2012, GenOn announced that it intends to merge with NRG  to form an approximately 47,000 megawatt industry leader that will keep the NRG name.  Importantly, previously announced GenOn deactivations, including the Potomac River station, will stay on schedule. 
  •  GenOn PRGS Retirement Date Confirmed
    On July 3, 2012, GenOn confirmed that the retirement date for the Potomac River Generating Station facility will be October 1, 2012. This date was agreed upon by the City and GenOn as part of the Amendment to Project Schedule and Agreement signed by both parties on August 29, 2011. For more details, click on the following link:
  • Virginia DEQ Issued Consent Order to GenOn PRGS
    The Virginia DEQ executed a consent order issued to GenOn Potomac River LLC regarding violations of the operating permit that happened at the Potomac River Generating Station (PRGS) located in Alexandria. As a result, GenOn agrees to pay a civil charge of $280,704 within the next 30 days. Violations related to this  consent order include the following:
    • The CEMS (Continuous Emissions Monitoring System) data submitted by the plant indicated that on six occasions during June-July 2011, the 30-day rolling average NOx emissions were 0.28 lb/MMBtu, compared to the permitted limit of 0.27 lb/MMBtu as stipulated by the Permit Condition 28.
    • No water fogging system was installed within the enclosure of the bottom ash silo, which violates the Permit Condition 10.  Please note that this is different from the fogging system installed on the fly ash loading areas as part of the Phase I project.
  • Grid Operator PJM (Pennsylvania New Jersey Maryland Interconnections) found no reliability issues related to the planned retirement of the Potomac River Generating Station
    The City and GenOn signed an Amendment to the Project Schedule and Agreement on August 29, 2011 which stipulates the retirement of the Potomac River Generating Station (PRGS) on October 1, 2012, subject to PJM finding that the facility is no longer needed for reliability as of the date of the retirement.  Per this Amendment, GenOn sent a letter to PJM Interconnection, LLC, to request the deactivation (i.e., retirement) of the Potomac River Generating Station on October 1, 2012. Responding to this request, PJM performed a detailed analysis of the PJM Transmission System and did not identify any reliability violations resulting from the requested deactivation of the PRGS facility. Similarly, PEPCO Transmission carried out the same analysis for its lower voltage system and found no reliability violations. The PJM analysis thus concluded that all five generating units of PRGS could actually be deactivated at any time. This clears the path for PRGS facility to be retired by the agreed upon date of October 1, 2012. Click  here to see the written response from PJM.
  • MCMG Meeting was held on September 29, 2011 to Discuss the City/GenOn Amended Agreement Signed on August 29, 2011. 
  • Potomac River Generating Station to Close
    The City of Alexandria and GenOn Energy reached an agreement to permanently close the company's Potomac River Generating Station, which began operating in 1949.  Under the terms of the agreement, GenOn agreed to retire the generating station by October 1, 2012, or, if the plant was needed beyond that date for reliability purposes, as soon as it would be no longer needed. The Mirant Community Monitoring Group met on  September 29 to update members of the public on the agreement to permanently close the GenOn Power River Generating Station. For more information on the closure of the generating station, read the news releaseClick here to see the signed agreement.  

Mirant Community Monitoring Group (MCMG)

MCMG (MCMG) was established by the City Council in 2004 to serve as a central information-receiving and monitoring group for issues involving the Mirant Potomac River Generating Station. The group is composed of eight members: Poul Hertel, Elizabeth Chimento, a representative from North Old Town Independent Citizens Association (NOTICe), a representative from Marina Towers, a representative from the Northeast Citizens Association, a representative from the Environmental Policy Commission, and two members of Council: Del Pepper and Paul Smedberg.

The primary objectives of MCMG are to receive reports and track the progress involving Mirant's ongoing permit and regulatory issues, its compliance with the consent decree and consent order, and to act as a forum to discuss technical issues such as the downwash modeling. Members of the monitoring group provide feedback to City Council and City staff and assist in the dissemination of information to the wider stakeholder community. Such dissemination involves community meetings and/or information sessions hosted by the monitoring group.

PRGS Monitoring Group Members

  • City Councilwoman Redella S. Pepper (Co-Chair)
  • City Councilman Paul C. Smedberg (Co-Chair)
  • Environmental Policy Commission Steve Walz, Citizen Member
  • North Old Town Independent Citizens Association (NOTICe) Roger Waud, President of NOTICe,
  • North East Citizens Association Steve Troxel, Member
  • Marina Towers Mary Harris, Member, Marina Tower Condo Association
  • Citizen member Poul Hertel
  • Citizen member Elizabeth Chimento

Additional Information