Using Backup Generators for Meeting Peak Electricity Demand: A Sensitivity Analysis on Emission Controls, Location, and Health Endpoints
Elisabeth A. Gilmore, Peter J. Adams, Lester B. Lave
Journal of the Air and Waste Management Association
1 g/m 3 ) in Atlanta and Chicago. The NO emissions also Generators installed for backup power during blackouts could help satisfy peak electricity demand; however, many are diesel generators with nonnegligible air emissions that may damage air quality and human health. The full (private and social) cost of using diesel generators with and without emission control retrofits for fine particulate matter (PM 2.5 ) and nitrogen oxides (NO x ) were compared with a new natural gas turbine peaking
... . Lower private costs were found for the backup generators because the capital costs are mostly ascribed to reliability. To estimate the social costs from air quality, the changes in ambient concentrations of ozone (O 3 ) and PM 2.5 were modeled using the Particulate Matter Comprehensive Air Quality Model with extensions (PMCAM x ) chemical transport model. These air quality changes were translated to their equivalent human health effects using concentration-response functions and then into dollars using estimates of "willingness-to-pay" to avoid ill health. As a case study, 1000 MW of backup generation operating for 12 hr/day for 6 days in each of four eastern U.S. cities (Atlanta, Chicago, Dallas, and New York) was modeled. In all cities, modeled PM 2.5 concentrations increased (up to 5 g/m 3 ) due mainly to primary emissions. Smaller increases and decreases were observed for secondary PM 2.5 with more variation between cities. Increases in NO x emissions resulted in significant nitrate formation (up to IMPLICATIONS Using installed backup generators to peak meet electricity demand for approximately 200 hr/yr is cost-effective compared with constructing a new dedicated peaking plant. Retrofitting these generators with emission controls for PM 2.5 and NO x allows them to operate without severe air quality degradation and adverse human health effects. Modeling the air quality effects with a chemical transport model is necessary to evaluate this strategy. caused O 3 decreases in the urban centers and increases in the surrounding areas. For PM 2.5 , a social cost of approximately $2/kWh was calculated for uncontrolled diesel generators in highly populated cities but was under 10 ¢/kWh with PM 2.5 and NO x controls. On a full cost basis, it was found that properly controlled diesel generators are cost-effective for meeting peak electricity demand. The authors recommend NO x and PM 2.5 controls.