• Objective: To determine the cost savings of charging various
electric vehicles with a residential solar PV system, compared to
charging without one (i.e. purchasing the required electricity
from the utility) and compared to using an average vehicle with
• Analysis assumptions:
• The 2017 BMW i3 BEV assumes a 60 Amp-hour battery.
• Solar electricity estimates are determined using solar radiation values for state capitals from Home Solar Discover.
• Solar generation figures are based on an average-sized residential solar PV system of 5 kW that is operational for 25 years.
• The default PV installation cost is estimated to be $3.50/watt (not including the 30% federal tax credit).
• Financing costs are not included - this analysis assumes an outright purchase of the solar PV system.
• Maintenance costs of the residential solar PV system are estimated to be 10% of the initial cost of installation.
• Where available, state-based solar tax credits were also included in the levelized cost calculations (other incentives, such as performance payments or property tax exemptions, are not included).
• Utility rates are based on the monthly residential rate data set as reported by the EIA and are averages computed using the last available 12 months in the dataset. Latest Utility Rates: December 2017.
• Vehicle fuel economy data is from the U.S. Department of Energy (www.fueleconomy.gov).
• The average fuel economy of a 2017 vehicle is 26 MPG according to the U.S. Department of Energy (www.fueleconomy.gov).
• Monthly average retail (regular) gasoline prices are from the EIA for December 2016.
• Financial estimates don't include the cost of financing the EV.