The U.S. Environmental Protection Agency proposes to approve a NOx-control plan from the state of Nevada that would require new emissions controls for the coal-fired Reid Gardner power plant of NV Energy (NYSE: NVE).
EPA said in an April 12 Federal Register notice that it plans to approve and partially disapprove the remaining portion of a revision to the Nevada State Implementation Plan (SIP) to implement the regional haze program for the first planning period through July 31, 2018. The agency wants to approve the part of Nevada’s Regional Haze SIP that requires Best Available Retrofit Technology (BART) for emissions of NOx from Units 1 and 2 at the Reid Gardner Generating Station (RGGS). EPA is proposing to disapprove the NOx emissions limit for Unit 3.
EPA is also proposing, under a plan that is up for comment until May 14, to disapprove the provision of the RGGS BART determination that sets a 12-month rolling average for RGGS Units 1-3.
EPA is proposing a Federal Implementation Plan (FIP) that establishes certain requirements for which the state of Nevada, in a March 22 letter, has agreed to submit a SIP revision. The FIP sets an emissions limit of 0.2 lbs/MMBtu for Unit 3 as BART and requires the determination of emissions from Units 1-3 based on a 30-day rolling average (averaged across all three units).
In a prior action, EPA approved Nevada’s Regional Haze SIP except for its BART determination for NOx for RGGS Units 1-3.
In its BART determination for RGGS, Nevada regulators considered several control technologies, including selective catalytic reduction (SCR), cheaper but less effective selective non-catalytic reduction (SNCR) and rotating overfire air (ROFA) with Rotamix. Nevada concluded that SCR would result in a very small incremental improvement of visibility, which did not justify the incremental cost of installing SCR. EPA said its analysis was a bit different, but that it supports Nevada’s decision to establish a NOx BART emission limit that could be achieved with ROFA and Rotamix (or SNCR) rather than requiring an emission limit consistent with SCR.
EPA said it considered the comments that it received on its June 22, 2011, proposed approval. It also conducted an independent modeling analysis to evaluate the incremental visibility improvement attributable to the NOx emission rates indicated in the RH SIP. That analysis shows that SCR controls at RGGS would not result in enough incremental visibility improvement at a single Class I area to justify the incremental cost of the technology.
So, the federal agency is proposing to approve Nevada’s determination that NOx BART for Units 1-2 is a limit of 0.2 lbs/MMBtu, which can be achieved with ROFA with Rotamix, or with SNCR with low-NOx burners (LNB) and overfire air (OFA). It proposes to disapprove Nevada’s NOx BART determination for RGGS Unit 3 and the SIP’s provision to measure NOx emissions from Units 1-3 on a 12-month rolling average. The FIP proposes a NOx BART emissions limit for RGGS Unit 3 of 0.2 lbs/MMbtu and a requirement that NOx emissions for RGGS Units 1-3 are to be measured on a rolling 30-day average (across all three units).
RGGS is a coal-fueled plant with four operating units producing a total of 557 MW. Three of the units, built in 1965, 1968, and 1976, are BART eligible and were determined by the state of Nevada to be subject to BART. Each of these units produces about 100 MW. At present, the units are equipped with LNB and OFA, mechanical collectors for particulate control, wet scrubbers that use soda ash for SO2 removal and recently installed baghouses.
In its Feb. 24 annual Form 10-K report, NV Energy (NVE) said that the impacted regional haze BART units are RGGS Units 1-3; the gas/oil-fired Ft. Churchill Units 1-2; and the gas/oil-fired Tracy Units 1-3. The submitted BART SIP contains targeted emission rates and compliance with the state’s BART program can be achieved through options such as retrofit of emission reduction equipment on the affected units, or retirement of those units, NV Energy noted.
“On June 9, 2011, the EPA published in the Federal Register its draft proposal to approve Nevada’s Regional Haze Plan as meeting the requirements of the Clean Air Act,” the Form 10-K added. “However, in announcing its final approval in December 2011, the EPA opted to take no action specifically on the BART determination for nitrogen oxide (NOx) at the Reid Gardner Generating Station, stating that it intends to propose action on those units at a later date and take public comment in the future. The EPA’s final approval did include the state’s proposed BART determinations for SO2 and particulate matter for Reid Gardner Generating Station, as well as the BART controls proposed for all of the other NVE affected units.”
Given the final EPA action in December, NV Energy said it is implementing the approved portions of the rule which will require compliance by Jan. 1, 2015. It intends to retire Tracy Units 1-2 and install retrofit controls on Tracy Unit 3 and Ft. Churchill Units 1-2.