Sources

Fuel Savings

Electric vehicles (EVs), both battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs), are less expensive to fuel than gasoline vehicles. According to the Department of Energy, "EVs convert over 77% of the electrical energy from the grid to power at the wheels," while for internal combustion engine vehicles (ICEVs) that figure is "about 12%–30% of the energy stored in gasoline."

To estimate fuel savings, we compare the fuel costs of each vehicle type independently and compare the difference. The key variables used in the calculation are different for each power-train.

Internal Combustion Engine Vehicles (ICEVs)

• the price per gallon of gasoline
• miles driven
• ICE efficiency, expressed as miles per gallon

Battery Electric Vehicles (BEVs)

• the price per kilowatt hour of electricity
• miles driven (the same figure used in the ICEV calculation)
• BEV efficiency, expressed as kilowatts per 100 miles (as reported by FuelEconomy.gov)

Example for BEVs compared to ICEVs

If gasoline costs $4 per gallon, electricity costs $0.20 per kWh, an ICE vehicle covers 27 miles per gallon and the BEV consumes 28 kWh per 100 miles, the savings over 10,000 miles would be over $900 per year.

Plug-In Hybrid Electric Vehicles (PHEVs)

To evaluate the fuel costs of a PHEV, we calculate the costs for two driving modes: all-electric and traditional hybrid. The percentage split between these two drive modes is sourced from an SAE International report and is based on the number of miles the PHEV can drive solely on battery. A PHEV with a higher battery only range will drive a higher percentage of miles solely using the battery. The sum of the fuel costs in each drive-mode is the total fuel cost for the vehicle.

All-electric mode (powered solely by electricity stored in the battery)

• the price per kilowatt hour of electricity
• miles driven (the same figure used in the ICEV calculation)
• Percentage of driving done in all-electric mode as per the SAE International report
• PHEV efficiency in all-electric mode, expressed as kilowatts per 100 miles (as reported by FuelEconomy.gov)

Hybrid mode (powered by gasoline and regenerated electricity)

• the price per gallon of gasoline
• miles driven (the same figure used in the ICEV calculation)
• Percentage of driving done in all-hybrid mode (the inverse of the all-electric mode)
• PHEV efficiency in traditional hybrid mode, expressed as miles per gallon.

Example for PHEVs compared to ICEVs

In a scenario similar to the one above, if gasoline costs $4 per gallon, electricity costs $0.20 per kWh, an ICE vehicle covers 27 miles per gallon, the PHEV consumes 28 kWh per 100 miles in all-electric mode, the PHEV covers 42 miles per gallon in hybrid mode, and the PHEV is driven in all-electric mode for 68% of the miles (based on a 40 mile all electric range), the savings over 10,000 miles would be just under $800 per year.

It's important to note that actual fuel savings may vary based on factors such as driving style, energy prices, and local conditions.

Maintenance Savings

Electric vehicles (EVs) cost significantly less to maintain than gasoline vehicles, thanks to their simpler design. Electric engines have far fewer moving parts than internal combustion engines, which reduces the need for repairs and routine maintenance.

According to the Office of Energy Efficiency and Renewable Energy, battery electric vehicles (BEVs) have 40% lower scheduled maintenance costs than internal combustion engine vehicles (ICEVs). Here's how maintenance costs per mile compare across fuel types:

• ICEVs: $0.101 per mile
• Hybrid Electric Vehicles (HEVs): $0.094 per mile
• Plug-in Hybrid Electric Vehicles (PHEVs): $0.090 per mile
• BEVs: $0.061 per mile

Based on the study, a driver traveling 10,000 miles annually would save over $400 per year in maintenance costs. An ICE vehicle would cost $1,010 in maintenance while a BEV would cost $610. A PHEV would have a modest savings of $110 compared to an ICEV.

The lower costs for BEVs are due to their lack of oil changes, reduced brake wear from regenerative braking, and fewer moving parts that can fail. While the precise maintenance savings will vary depending on driving habits, vehicle type, and other factors, BEVs consistently provide significant cost advantages in this area.

It's important to note that maintenance savings may vary based on factors such as driving style, local prices, and local conditions.

Emissions Reduction

Carbon emissions reductions are assessed using the model designed by the Department of Energy's Alternative Fuels Data Center (see model assumptions) and applying it to a specific example. Similar to the Fuel Savings above, we compare vehicle type independently and compare the difference. Instead of assessing fuel costs, we assess the emissions of fuel consumed.

Emissions from gasoline consumption are assessed using 23.7 lbs. of CO2e per gallon, as per the GREET Model developed by Argonne National Laboratory.

Emissions from electricity are assessed by calculating an "average emissions from generated electricity" based on a state of residence using data from the U.S. Energy Information Administration's Electric Power Annual report.

Emissions from both fuel sources match those of the AFDC model. Extrapolating from the AFDC model, the key variables used in the emissions calculation are different for each power-train.

Internal Combustion Engine Vehicles (ICEVs)

• emissions from gasoline consumption (this is a static figure)
• miles driven
• ICE efficiency, expressed as miles per gallon

Battery Electric Vehicles (BEVs)

• average emissions from generated electricity (adjusted based on a state of residence)
• miles driven (the same figure used in the ICEV calculation)
• BEV efficiency, expressed as kilowatts per 100 miles (as reported by FuelEconomy.gov)

Example for BEVs compared to ICEVs

If a gallon gasoline contributes 23.7 lbs of CO2e (constant input per AFDC model), a kWh contributes 0.43 lbs of CO2e (based on a resident of California), an ICE vehicle covers 27 miles per gallon and the BEV consumes 28 kWh per 100 miles, the emissions reductions over 10,000 miles would be over 7,500 lbs of CO2e.

Plug-In Hybrid Electric Vehicles (PHEVs)

To evaluate the emissions of a PHEV, we calculate the emissions for two driving modes: all-electric and traditional hybrid. The percentage split between these two drive modes is sourced from an SAE International report and is based on the number of miles the PHEV can drive solely on battery. A PHEV with a higher battery only range will drive a higher percentage of miles solely using the battery. The sum of the emissions in each drive-mode is the total emissions for the vehicle.

All-electric mode (powered solely by electricity stored in the battery)

• average emissions from generated electricity (adjusted based on a state of residence)
• miles driven (the same figure used in the ICEV calculation)
• Percentage of driving done in all-electric mode as per the SAE International report
• PHEV efficiency in all-electric mode, expressed as kilowatts per 100 miles (as reported by FuelEconomy.gov)

Hybrid mode (powered by gasoline and regenerated electricity)

• emissions from gasoline consumption (this is a static figure)
• miles driven (the same figure used in the ICEV calculation)
• Percentage of driving done in all-hybrid mode (the inverse of the all-electric mode)
• PHEV efficiency in traditional hybrid mode, expressed as miles per gallon.

Example for PHEVs compared to ICEVs

In a scenario similar to the one above, if a gallon gasoline contributes 23.7 lbs of CO2e (constant input per AFDC model), a kWh contributes 0.43 lbs of CO2e (based on a resident of California), an ICE vehicle covers 27 miles per gallon, the PHEV consumes 28 kWh per 100 miles in all-electric mode, the PHEV covers 42 miles per gallon in hybrid mode, and the PHEV is driven in all-electric mode for 68% of the miles (based on a 40 mile all electric range), the emissions reductions over 10,000 miles would be over 6,100 lbs of CO2e.

It's important to note that actual emissions may vary based on factors such as driving style, energy sources, and local conditions.