NRG Texas LP
NRG Texas LP's investment in new, innovative technologies to reduce emissions at our W.A. Parish Electric Generating Station has set the example for others to follow. The facility, one of the largest coal and gas-fired power plants in the United States, is achieving NOx emission rates more than 90 percent below baseline levels on the coal-fired units and is likely the lowest NOx emitting coal-fired facility in the nation and quite possibly the world. NRG Texas LP initiated this project in 1999, in response to anticipated NOx reduction requirements of the Texas State Implementation Plan (SIP).
NRG Texas LP has committed to and achieved substantial NOx emission reductions exceeding regulatory requirements. To a great extent these reductions have been achieved at the coal-fired W.A. Parish Electric Generating Station. Major modifications to the W.A. Parish coal-fired units began in 1999. Units 5 and 6 were retrofit with state-of-the-art, Low NOx Burners (LNB) from the Babcock & Wilcox Company.
These installations included (1) the nation's first commercial application of one type of LNB/OFA system, and (2) the nation's first LNB/OFA system guaranteed by the vendor to achieve the EPA's stringent New Source Performance Standards (NSPS) for new generating units. These controls reduced NOx emissions from the W.A. Parish Station by 50-60 percent, or nearly 20,000 tons per year from 1998 baseline levels.
NRG Texas LP has also installed selective catalytic reduction (SCR) technology on the four W.A. Parish coal-fired generating units to reduce emissions by an additional 80-85 percent. The SCRs achieve a NOx rate of 0.04 lb/MMBtu, a value far below the current NSPS equivalent rate of 0.15 lb/MMBtu as well as recent Best Available Control Technology determinations for coal-fired generating units. The SCR systems for Units 5-8 went into service between January 2003 and April 2004.
NRG Texas LP has spent more than $750 million on new emission controls since 1999, including more than $400 million at the W.A. Parish Station. NRG Texas LP has met the challenge of investing in emissions control equipment while maintaining reliability and availability in a competitive market. This technology is applicable to coal-fired boilers in both electric generating and industrial applications.
Details of Reductions
Additional Information :
The new burners and Over-fire Air (OFA) ports reduced the Units NOx emissions from 0.35 lbs/mmBtu to approximately 0.16 lbs/mmBtu. Units 7 and 8 were retrofit with TFS 2000 firing systems from Alstom. The TFS 2000 system consists of state-of-the-art LNB, close-coupled OFA ports, and two rows of separated OFA ports, which reduced the NOx emissions of Units 7 and 8 from 0.40 lbs/mmBtu to approximately 0.15 lbs/mmBtu.