Air quality impacts of using overnight electricity generation to charge plug-in hybridelectric vehicles for daytime use

Abstract

The air quality impacts of replacing 20% of the gasoline powered light duty vehicle milestraveled with plug-in hybrid electric vehicles (PHEVs) in the region served by thePennsylvania, New Jersey, Maryland classic grid are examined. Unutilized, base-loadnighttime electricity generating capacity is assumed to charge PHEVs that wouldsubsequently be used during urban commutes. The net impact of this scenario on theemissions of precursors to the formation of ozone is an increase in nitrogen oxide (NOx),volatile organic compound (VOC) and CO emissions from electricity generating unitsduring nighttime hours, and a greater decrease in NOx, VOC and CO from mobileemissions in urban areas during daytime hours. The changes in maximum daily 8 h ozoneconcentrations, predicted using a regional photochemical model (CAMx), are decreases inozone concentrations between 2 and 6 ppb that are widespread across the urban areas, andincreases in ozone concentrations of up to 8 ppb in highly localized areas. Air qualityindicators beyond maximum daily ozone concentration are also evaluated, and ingeneral indicate air quality improvements associated with the use of PHEVs.However, a limited number of air quality indicators worsened with the use ofPHEVs, suggesting that overall impacts of the use of PHEVs will be complex.