work underway on a water-discharge structure we designed for poor soil conditions
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air permitting support for peaking plant expansion

air permitting support for peaking plant expansion
client
NorthWestern Energy
location
Aberdeen, South Dakota

In 2010 Barr was engaged by NorthWestern Energy to prepare a Title V air permit modification for the company’s Aberdeen, South Dakota, peaking plant. The project added two dual-fuel combustion turbines in a “twin pack” configuration to drive a single 59MW generator for peaking duty. The permit application requested an annual operating-hours limit to keep the project classified as “minor” under PSD regulations.

Barr prepared an emissions impact summary for several operating scenarios, the worst of which still provided an operating-hours limit higher by a factor of three than the anticipated annual hours of operation. Barr worked with the South Dakota Department of Environment and Natural Resources to provide a conservative demonstration of modeled compliance with the PM2.5 ambient air-quality standard while guidance on fine particulate modeling was still being developed by the U.S. Environmental Protection Agency. In addition, we helped evaluate monitoring options to compare continuous emission monitoring systems (CEMS) and parametric monitoring. 

Also, because additional fuel-oil storage was anticipated to be constructed on the site, Barr provided consulting on the need for an integrated contingency plan (ICP) for spill response, including the requirements for a federal response plan.

Construction on the plant began in 2011; commercial operation began in May 2013.