MPGe: What Is It? Explaining The New Fuel Efficiency Rating For Electric Vehicles And Hybrids

MPGe is a simple yet crucial metric that potential purchasers of electric cars and plug-in hybrids should be aware of.

You’ll notice a little difference on the windscreen label when looking for any kind of electric vehicle: A small “e” has appeared next to the traditional “MPG” fuel rating.

This is so that hybrid and fully electric vehicles now fall under a new fuel efficiency category established by the Environmental Protection Agency (EPA) in 2010. It stands for miles per gallon of gasoline equivalent, and automakers must display it according to government regulations.

What Exactly Does MPGe Mean?

The greater the MPGe, the better, similar to miles per gallon (MPG). It determines how much distance a vehicle can go on a certain amount of fuel, whether that fuel is gasoline or electricity. This has an impact on your driving experience in terms of how often and how much it costs to refuel.

The EPA website explains that this is “similar to MPG, except it shows the number of miles the vehicle can drive using a quantity of fuel with the same energy content as a gallon of gasoline, rather than miles per gallon of the car’s fuel type” (Opens in a new window).

According To The EPA, One Gallon Of Fuel Equals 33.7 Kilowatt Hours Of Electricity For Calculating MPGe.

“How far can I drive on a gallon of gas?” is a simple notion, therefore it’s much simpler for us to understand that MPG is also a measurement of the economy,” explains automotive writer Tim Stevens. “How far can my automobile go on 33.7 kWh of power, in terms of MPGe? That is far more difficult to picture. We can convert between the two since a gallon of gasoline is thought to have the same amount of energy as 33.7 kWh.”

MPGe For Hybrids, Plug-In Hybrids, And Electric Vehicles

Only EVs and plug-in hybrids are eligible for MPGe. Normal hybrids continue to rely mostly on gasoline and only include a tiny electrical motor for ancillary purposes like air conditioning. Let’s take the hybrid, plug-in hybrid, and completely electric versions of the Kia Niro as an example.

Notice that the Niro hybrid gets 49–53 MPG; it doesn’t specify MPGe. However, compared to an automobile driven only by gas, the MPG is still improved by the addition of electricity.

A plug-in hybrid vehicle, or PHEV, can go up to 33 miles on electricity before switching to gasoline. The Niro has a 108MPGe combined rating. You may spend a whole week without using a gallon of petrol if your PHEV has a 30-mile range, your commute is just 15 miles, and you charge it every night, claims Stevens. In such a situation, a plug-in hybrid’s MPGe is determined by how far it can go on 33.7 kWh of power, much like an electric vehicle. After the electric power runs out on a longer trip, the combined MPGe combines the fuel efficiency of the gas engine with the electric motor.

The Niro is a totally electric car with a 113MPGe rating. Because full EVs don’t have a backup gas engine, they only operate on electricity, hence Kia removed the word “combined” from the EV’s name.

Is High Mpge Equivalent To High Range?

A high MPGe does not imply a greater range on its own. This may seem contradictory since we often assume that a vehicle with a high MPG would need to refuel less frequently (but the size of the tank also factors in, too).

Since MPGe measures a car’s efficiency rather than its range, it may be a bit difficult to understand, according to Stevens.

Energy efficiency is significantly less of a limiting constraint for the majority of EVs today than the battery, which is similar to the size of the gas tank. EV cars are limited to shorter ranges since EV batteries are not yet as energy dense as users would prefer. Therefore, even if the vehicle uses energy more effectively, it still may not be able to store as much energy at once.

The EV has the best MPGe but the smallest overall range of the three, using the Kia Niro as an example.

Niro EV: 113MPGe, a range of 253 miles

Niro plug-in hybrid has a range of 510 miles and 108MPGe.

Niro hybrid: around 50 MPG, range of 479–588 miles

Is Range or MPGe Priority Better?

Your driving style will determine this. Most individuals do not often need the 200–400 miles of range that the majority of EVs have. Choose a vehicle with the best MPGe you can find if conserving money when driving around town is your top priority—perhaps you use a gas or hybrid car for longer journeys. Each vehicle’s anticipated gas savings are shown on the EPA label.

A higher range is necessary to reduce the number of fuel stops along the route for longer journeys. The winning combination combines the maximum miles of range and MPGe that you can find. It implies that the battery can store more energy at once and use that energy for longer.