What is MPGe?
Before 2020 comes to an end, nearly every automaker in the U.S. will be marketing at least one fully electric vehicle. For folks who are concerned about climate change, these new EVs are a welcome sight. Up until now, EVs have been shunned because of their limited range, but improved technologies now allow them to travel much further on a single charge. Hybrids are very efficient vehicles without major range limitations, but an EVwill never sip a single drop of gasoline. Consumers are understandably concerned about range, but energy efficiency is also very important to the most environmentally thrifty.
One would think that an EV with the best mileage would also have the longest range, but due to some quirks of physics this is not the case. Bigger batteries provide added range, but the batteries are very heavy. As range goes up, efficiency tends to go down. With new advances, you now get more of both, especially from Tesla.
While the range of an EV is easy to grasp, its efficiency is not. The Environmental Protection Agency rates the fuel economy of EVs using a measurement called “miles per gallon equivalent” or “MPGe”. Electricity doesn’t come in gallons, so the terminology can be confusing. The figure represents the number of miles that a vehicle can travel on a quantity of electrical energy that is equivalent to the energy provided by one gallon of gasoline. When you torch a gallon of unleaded, you release 115,000 British Thermal Units of energy. Don’t try this at home. It takes 33.7 kilowatt-hours of electricity to produce the same 115,000 BTUs. So if an EV battery uses 33.7 kilowatt-hours of electricity to propel the vehicle 141 miles, it earns an impressive rating of 141MPGe.
141 actually is the highest MPGe rating on today’s EV market, awarded to the 2020 Tesla Model 3 Standard Range Plus. This amazing Tesla gets 148 in the city and 132 on the highway. It can also go 250 miles on a single charge. The 2020 Hyundai Ioniq EV comes in a close second with 145 in the city, 121 on the highway, for a combined rating of 133. The Ioniq EV was top dog for efficiency in 2019, but Hyundai redesigned the car this year to give it more range and had to sacrifice a little bit of fuel economy. The 2020 still travels a respectable 170 miles per zap.
The EPA’s combined mileage rating based on two separate ratings for city and highway driving has been a useful MPG format for a long time. An EV window sticker prominently showcases the combined MPGe using the largest font size. You’ll have to look closer to determine the vehicle’s range. MPGe figures can be hard to find on automaker web sites, but there’s a great chart at www.
fueleconomy.gov that ranks the MPGe figures for all EVs, and you can click on any vehicle to learn more.
EPA mileage ratings are approximations for all vehicles, varying considerably due to differences in driving behavior and other factors. Mello drivers can get a lot of miles out of their EVs. Vehicles powered by electricity get better mileage in the city than they do on the highway; just the opposite of cars with internal combustion engines. It’s another quirk of physics that has to do with a cool thing called “regenerative braking.” As an EV brakes, its inertia drives a generator that feeds electricity back into the battery where it can be used again. Hybrids also regenerate electricity. Sadly, MPGe goes down in colder climates. In most parts of California, this isn’t an issue.
If you’re considering an EV to help lower your carbon footprint, don’t be swayed by arguments about the fossil fuel that went up in smoke to produce your EV’s electricity. Even when upstream emissions are taken into account, EVs are much cleaner than gasoline burners, especially here in California where a lot of electricity is generated using renewables. Many EV owners also have solar panels on their roofs that they use to charge up, making every mile they drive truly emission free. If you choose to drive an EV, you can be confident that you truly are helping to fight climate change. As the grid gets greener, so will your EV. If you want the greenest car money can buy, look for the EV with the highest MPGe.