Owner/Client:      County of Placer

Placer County is planning a 2-megawatt wood-to-energy biomass facility proposed in the eastern part of the county. The County’s objectives included the air quality benefits associated with reduced pile burning of forest thinning debris and improved fuels management to reduce the potential for catastrophic wildfire in the Sierra Nevada. Ascent’s climate specialists quantified the net change in GHGs associated with construction and operation of the facility. This included the estimation of GHGs associated with combustion by the power plant, trucks hauling biomass to the plant, fuel chipping and processing, equipment in the fuel yard, employee trips, water consumption, wastewater treatment, and project construction. Ascent examined both gasification and direct combustion technologies. The analysis also quantified the level of GHGs that would be avoided due to the reduction in open burning of biomass piles, which is the current fate of the woody biomass fuel. Ascent used these calculations to estimate the GHG efficiency by which the facility would generate electricity, expressed in metric tons of carbon dioxide equivalent per megawatt-hour. Because this analysis was part of the project EIR being prepared by Ascent, our GHG specialists also developed a threshold of significance that is tied to California’s Renewable Energy Standard, which was passed under the mandate of the California Global Warming Solutions Act of 2006 (AB 32).