Miles Per Kilowatt Hour is the new Miles Per Gallon
Courtesy of autoevolution.com
Vehicle energy efficiency–you know this as Miles Per Gallon (MPG)
A gasoline-powered vehicle’s range is the product of fuel efficiency and fuel capacity. E.g., an internal combustion engine (ICE)-powered automobile with 25 miles per gallon (MPG) fuel efficiency and a 10 gallon fuel tank has a range of 250 miles.
EV energy efficiency–will become known as Miles Per Kilowatt Hour (MPkWh)
An electric vehicle’s range is the product of energy efficiency and energy capacity. E.g., an EV with 3 miles per kilowatt hour (MPkWh) energy efficiency and a 24 kWh battery pack has a range of 72 miles.
Typical EV energy efficiency (miles per kWh):
- Electric automobile: 3-4 MPkWh (miles/kWh) (combined city/highway)
- Electric motorcycle: 13 MPkWh city, 6-8 MPkWh highway
- Electric bike: 62 MPkWh
What energy efficiency do you think electric airplanes have?
e-airplane energy efficiencies
Although some people “joy ride” in automobiles, we don’t generally care about an automobile’s time endurance on a tank of gas. But many pilots joy ride in aircraft and want to maximize their time flying around the patch. I.e, we pilots care about hours per gallon as well as miles per gallon.
With that in mind, we should think of two types of energy efficiency for electric aircraft: range efficiency and endurance efficiency.
Range = range efficiency (distance/energy) * energy capacity (energy)
Examples of e-airplane range efficiency:
- GW280 eSpyder range efficiency: 8.5 MPkWh (miles/kWh) (at 38 MPH)
- ElectraFlyer-ULS range efficiency: 10.4 MPkWh (miles/kWh) (at 40 MPH)
- e-Genius range efficiency: 13.8 MPkWh (miles/kWh) (at 93 MPH)
Endurance = endurance efficiency (duration/energy) * energy capacity (energy)
Examples of e-airplane endurance efficiency:
- GW280 eSpyder endurance efficiency: 0.225 hours/kWh (= 13.5 minutes/kWh) (at 38 MPH)
- ElectraFlyer-ULS endurance efficiency: 0.260 hours/kWh (= 15.6 minutes/kWh) (at 40 MPH)
- eGenius: endurance efficiency: 0.148 hours/kWh (= 8.88 minutes/kWh) (at 93 MPH)
Are you surprised at the range efficiencies of e-airplanes vs electric automobiles, motorcycles, and bikes?