Choose a representative vehicle to see how much of the original energy
becomes useful energy moving the vehicle down the road.
Example vehicle
Vehicle “rolling down the road” efficiency
Energy source
Energy-source efficiency
Total Operating Efficiency
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Energy pathway
100 units of original energy
Explore the assumptions (limited adjustments)
These controls allow a small change around the default assumptions.
They are intentionally limited so the calculator remains an educational
model rather than a free-form simulation.
Approximate representative values only. Actual efficiency varies with
vehicle configuration, driving conditions, operating conditions and
energy source. The advanced-hybrid example is included to illustrate
current technology potential and is not intended to imply U.S. availability.
The Effficiency Calculator is based on the US Grid, which is heavily slanted toward Natural Gas, Coal and Nuclear Power – Solar and Wind are currently less than 20% of the US Electric Grid.
Another article will go into detail on our assumptions – but a general look is as follows:
With Electric Vehicles The US DOE estimated approximately 40% of the Nat Gas Energy Makes it to your wall socket. 12 to 15% is then lost in Charging and general standby in your Garage or Parked. Another 15% or more is then lost in the vehicle transmision, bearings, tires and more standby. Similar efficiency is calculated for Public Chargers – it is very similar in %
What’s up with the 70% EV, I Thought they were 85% to 90%? The 70% figure includes: 10 to 20% (avg 15%) charging loses. Faster Charging = Lower Losses. Rolling – moving – 10 to 15% is lost in heat from tires, in-car computers, pushing through air. Standby Losses – 5 to 10% is lost when car is generally inactive – bettery slow-drain and idle electric use. Since operation of an EV isn’t possible without these loses, a 70% baseline is defensible as fact.
With Gasoline Vehicles: Gasoline needs to be refined, stored, transported, etc. – resulting in a loss of approx 15% by the time it makes it into the fuel tank of a vehicle. Hybrids lead the pack of liquid fuel because they match the needed power almost perfectly – and regeneration from brakes and other methods keep things fairly efficient. Here is how a Hybrid works to help save energy. ICE Engines can operate with decent efficiency, however the losses are very high because they provide power (and wasted heat) 100% of the time they are operating.
Note that Efficiency is not the same as Cost or Price per Passenger Mile. Efficiency is “How much of the original Energy in the Fuel that we end up using for a task”.