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New Hampshire Department of Environmental Services

Final Temporary Permit Issued April 15, 2015
Installation of Air Pollution Controls
Public Service of New Hampshire d/b/a Eversource Energy
Schiller Station, Portsmouth, NH

On April 15, 2015, NHDES made a final decision to issue a Temporary Permit (permit to construct) authorizing the installation of air pollution control equipment at the Public Service of New Hampshire d/b/a Eversource Energy (Eversource) – Schiller Station facility in Portsmouth, New Hampshire.

On February 27, 2014, Eversource submitted an application for a Temporary Permit to install air pollution control equipment on two coal-fired electric generating units, SR4 and SR6.  The purpose of this project is to comply with standards established by the United States Environmental Protection Agency under the Code of Federal Regulations, 40 CFR Part 63, Subpart UUUUU, National Emission Standards for Hazardous Air Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units (Subpart UUUUU).

The proposed project involves the installation of two new air pollution control systems.  The first system is an activated carbon injection system, which injects activated carbon into the flue gas stream to react with and remove mercury emissions.  The activated carbon is then removed by the facility's existing particulate matter control equipment before the treated flue gas is discharged to the atmosphere.

The second system is a dry sorbent injection system, which injects a dry sorbent such as Trona (sodium sesquicarbonate) or sodium bicarbonate into the flue gas stream to remove acid gases such as hydrogen chloride and sulfur dioxide.  This system works in a similar manner to the activated carbon injection system, in that sorbent is injected into the flue gas stream to react with the acid gases, with the used sorbent removed prior to flue gases discharging to the atmosphere.

The Temporary Permit application also included a request by Eversource for a one year extension to comply with the requirements of Subpart UUUUU, from April 16, 2015 to April 16, 2016.

On February 10, 2015, NHDES published a public notice in the Union Leader and the Portsmouth Herald of its draft decision to issue a Temporary Permit.  NHDES also conducted a public hearing on March 18, 2015, at the Portsmouth City Council Chambers in Portsmouth, NH.  The purpose of this public hearing was to solicit comments on the draft decision.  NHDES received comments from multiple interested parties.  NHDES considered all comments in arriving at its final decision.

The final Temporary Permit is available from the link provided below.  Supporting documentation, including NHDES's response to comments and description of changes made as a result of comments, are also available via the links below.  Please direct any questions to Padmaja Baru at (603) 271-0905 or by e-mail at

Appeals and Offers to Enter into Settlement Discussions:

Any person aggrieved by this final decision may appeal to the N.H. Air Resources Council ("Council") by filing an appeal that meets the requirements specified in RSA 21-O:14 and the rules adopted by the Council, Env-AC 200.  The appeal must be filed directly with the Council within 30 days of the date of this decision and must set forth fully every ground upon which it is claimed that the decision complained of is unlawful or unreasonable.  Only those grounds set forth in the notice of appeal can be considered by the Council.

Information about the Council, including a link to the Council's rules, is available at (or more directly at  Copies of the rules also are available from the NHDES Public Information Center at (603) 271-2975.



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NH Department of Environmental Services | 29 Hazen Drive | PO Box 95 | Concord, NH 03302-0095
(603) 271-3503 | TDD Access: Relay NH 1-800-735-2964 | Hours: M-F, 8am-4pm

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