Electric Generator Permitting
Client: Green Mountain Power
Challenge
Green Mountain Power (GMP) currently provides one quarter of Vermont’s electricity. Given electricity demand, GMP decided to replace four of its older diesel electric generators with four new, low-emissions diesel electric generators.
Initiative
To evaluate potential air quality impacts associated with the four new generators at one of GMP’s substations in northern Vermont, RSG in 2005:
- Estimated short-term and annual emissions of criteria pollutants for all possible generator ratings (standby, prime, and continuous) and three different load-operating capacities (100%, 75%, and 50%)
- Conducted a Good Engineering Practice (GEP) stack height analysis
- Identified generator exhaust stack locations that would provide maximum dispersion of air pollutants, in conjunction with the GEP analysis
- Developed a computer-based air pollution dispersion model, using U.S. Environmental Protection Agency software, to estimate ground-level air pollutant concentrations
- Using the dispersion model, identified generator fuel use and exhaust stack parameters meeting National Ambient Air Quality Standards and Prevention of Significant Deterioration requirements
- Prepared air quality impact evaluation report for the Vermont Agency of Natural Resources (ANR)
Results
We identified a stack design that met both GMP’s operating requirements and pertinent air quality standards. The new stack design will afford improved dispersion of air pollutants, thereby benefiting local air quality. GMP received its air pollution permit from the ANR.
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