The costs of charging Plug-in Electric Vehicles (PEVs): Within day variation in emissions and electricity prices

The social costs of charging plug-in electrical vehicles (PEVs) that vary by times of day and by levels of emissions in electricity production are investigated. Using data available for the Sacramento area in the United States for 2013, we estimate marginal emission rates of electricity and marginal price of electricity provided for charging PEVs at different times of the day. As the marginal emission rates and wholesale electricity price have different daily patterns, there is a trade-off between emission and charging cost. Moreover, the estimates in the literature of the social costs for the most important emission, CO2, vary substantially, implying that the social cost of charging PEVs vary with the assumed cost. Simulations show that the charging time of lowest social costs for PEVs is found to be at midnight if the social cost of CO2 is not very high (<$90/ton), however, we find this pattern changes with an increase in the social cost of CO2. A high price of CO2 tends to shift the time of lowest social costs of charging to other times of day, thus, charging at workplaces during the daytime rather than at home overnight can reduce the social cost of charging PEVs.