The Environomics of Driving Electric Cars By Bob Waterstripe Electric Vehicles (EVs) are much more efficient than Internal Combustion Engine vehicles (ICEs) and use much less energy per mile. Electricity per mile is much cheaper than gasoline. Generating electricity to charge an EV results in much lower emissions per mile driven than an ICE burning gasoline. According to the U.S. Department of Energy, “EVs convert over 77% of the electrical energy from the grid to power at the wheels. Conventional gasoline vehicles only convert 12-30% of the energy stored in gasoline to power at the wheels.” 1 That huge advantage in energy efficiency is only part of the story. To make a fair comparison between ICEs and EVs, the “Miles per Gallon – equivalent” rating was invented for EVs. MPG-e is how many miles the EV can travel (city and highway combined) on 33.7 kWh of electricity, equal to the energy in one gallon of gasoline. Just like ICE vehicles have a wide range of MPG, EV models vary widely in MPG-e ratings, so the cost per mile varies as well. For example, a Tesla Model 3 achieves 142 MPG-e, combined highway and city, and is rated at 24 kWh per 100 miles. At $0.15 per kWh, it costs $3.60 for 100 miles, or 3.6 cents per mile. Of course grid electricity prices vary widely. In comparison, a Toyota Camry (2.5L) is rated at 32 MPG combined highway and city, and 3.1 gallons per 100 miles. At $3.50 per gallon, the cost of gas is $10.85 for 100 miles, or 10.85 cents per mile. That is, about triple the cost of powering the EV with grid power. And gas prices vary wildly as well. Anyway, the math is simple. Https://fueleconomy.gov/ has information about 300 EVs and virtually every gas and diesel car that exists. The carbon emissions of gasoline are well known: about 24 pounds per gallon, 5 from producing it and 19 from burning it. The emissions actually weigh about three times as much as the gasoline itself because carbon released in combustion combines with much heavier oxygen in the atmosphere to form carbon dioxide (CO2). The emissions associated with the Camry in our example are about 74.4 pounds per 100 miles, and will outweigh the 3,300-pound Camry itself every 4,450 miles. An EV has no tailpipe emissions, of course, but we must account for emissions from generating electricity to charge it. Emissions per kWh generated vary depending on the sources of energy at the power plants. Solar, wind, hydro and nuclear have no emissions at all, while natural gas and coal have various amounts. The U.S. Energy Information Administration 2 reports that emissions from generating electricity in Florida are a fairly typical (compared with other states) 1.54 pounds per kWh, and thus the Tesla in our example is responsible for 37 pounds of emissions per 100 miles using grid power, only half as much as the Camry. Even if using grid power for EVs reduces emissions by 50% compared to ICEs and cuts the fuel cost per mile by 70%, why stop there? With your own solar power, there are zero emissions per mile driving any EV, as well as zero cost per mile. That’s twice as good for the planet, and infinitely better for your personal wealth. Note: The term “Environomics” is from the 1993 economics classic Environomics: The Economics of Environmentally Safe Prosperity by Farid A. Khavari, Ph.D. 1. https://www.fueleconomy.go v/feg/evtech.shtml 2. https://eia.gov/environment/ emissions/state