Lower Emissions Milestones

1989 - Installed an Electrostatic Precipitator (ESP) at Merrimack Station on Unit One, resulting in no visible stack emissions from that unit.

1991 - Reduced sulfur dioxide (SO2) emissions by 40 percent, in compliance with the NH Acid Rain Law, through the use of low sulfur coal. This reduction was approximately the equivalent of the Clean Air Act Amendments, Title IV, Phase One, which became effective in 1995.

1992 - Gas conversion completed at Newington Station to allow for the burning of natural gas.

1995 - Merrimack Station Unit 2 became the first utility coal-fired boiler in the United States to install a Selective Catalytic Reduction (SCR) system. This installation resulted in a 65 percent reduction in nitrogen oxide (NOx) emissions from that unit. In addition, a Selective Non-Catalytic Reduction System (SNCR) was installed on Unit One to reduce NOx emissions.

1995 - Modifications, including the installation of low NOx burners at Schiller Station and boiler modifications at both Schiller and Newington Stations were completed in order to reduce NOx emissions.

1998 - Voluntarily installed additional catalyst material in the Merrimack Unit Two SCR system which resulted in an 85 percent reduction of NOx emissions. These reductions were of critical importance in a decision by the US Environmental Protection Agency (EPA) not to require automobile tailpipe emissions testing in New Hampshire.

1999 - Installed a SCR system on Merrimack Station's Unit One which reduced NOx emissions from this unit by 85 percent. This reduction in NOx emissions is equivalent to the removal of 700,000 automobiles from the road. As a result of this installation, NOx emissions from Merrimack Station are in compliance with the EPA's NOx standards for new power plants.

1999 - Installed a supplemental Electrostatic Precipitator (ESP) on Merrimack Station's Unit Two, eliminating the remaining visible smoke plume. With the installation of this ESP, Merrimack Station is in compliance with the EPA's opacity (smoke density) standards for new plants.

1999 - Installed a SNCR at Schiller Station. This installation, which has exceeded expectations since it began operation, has resulted in a 40 to 50 percent reduction in NOx emissions.

1999-2000 - Additional NOx reductions achieved at Newington Station following the installation of a combustion tempering system and boiler arch water system.

1999 - New pipelines installed, increasing the plant's capacity to burn natural gas and further reducing NOx emissions.

2001 - PSNH signs the New Hampshire Clean Power Act, a first-in-the-nation agreement that sets emissions reduction targets for carbon dioxide, sulfur dioxide and mercury.

In addition to reducing emission our environmental initiatives have earned PSNH a number of environmental awards.