Wheel-to-Wheel (WTW) Basics
This term represents the overall efficiency from primary energy source production to vehicle motion at the wheels.
What is Wheel-to-Wheel (WTW) efficiency?
The fuel cell technology most commonly used in hydrogen-powered passenger vehicles.
What is a Proton Exchange Membrane Fuel Cell (PEMFC)?
Alternative-fuel vehicle type with the highest WTW efficiency.
What is a Battery Electric Vehicle (BEV)?
A renewable fuel produced from vegetable oils and animal fats.
What is biodiesel?
Among gasoline, hydrogen fuel cells, and BEVs, this technology usually has the highest WTW efficiency.
What is a Battery Electric Vehicle (BEV)?
WTW efficiency consists of these two major stages.
What are Well-to-Tank (WTT) and Tank-to-Wheel (TTW) efficiencies?
Typical wheel-to-wheel efficiency range of hydrogen fuel-cell vehicles.
What is 25–40%?
Typical WTW efficiency range of modern BEVs.
What is 70–85%?
Ethanol is commonly blended with this conventional fuel.
What is carbon monoxide (CO)?
Approximate WTW efficiency of a conventional gasoline vehicle.
What is 15–25%?
This stage includes fuel production, processing, storage, and transportation.
What is Well-to-Tank (WTT) efficiency?
This process uses electricity to split water into hydrogen and oxygen.
What is electrolysis?
This component stores electrical energy in a BEV
What is a battery pack?
The wheel-to-wheel efficiency of biofuel vehicles is often limited by this engine type.
What is the internal combustion engine (ICE)?
Approximate WTW efficiency of a hydrogen fuel-cell vehicle.
What is 25–40%?
This stage measures how efficiently a vehicle converts stored fuel energy into useful motion.
What is Tank-to-Wheel (TTW) efficiency?
The color designation given to hydrogen produced using renewable electricity.
What is Green Hydrogen?
Regenerative braking helps improve efficiency by doing this.
What is recovering kinetic energy during braking?
Biodiesel generally provides lower emissions of this pollutant compared to diesel.
What is carbon monoxide (CO)?
Approximate WTW efficiency of a battery electric vehicle.
What is 70–85%?
The mathematical relationship used to calculate WTW efficiency.
ηWTW=ηWTT×ηTTW
A major challenge reducing hydrogen WTW efficiency.
What are compression, storage, and transportation losses?
Compared with hydrogen vehicles, BEVs require fewer of these energy conversion steps.
What are energy conversion processes?
A major advantage of biofuels compared with fossil fuels.
What is renewability and reduced lifecycle carbon emissions?
Rank these technologies from highest to lowest WTW efficiency: Gasoline ICE, Hydrogen Fuel Cell, Battery Electric Vehicle.
What is:
BEV > Hydrogen Fuel Cell Vehicle > Gasoline ICE Vehicle