The most energy efficient transport per passenger-kilometre: electric trains vs electric cars vs e-bikes

Electrifying a journey removes the tailpipe, but it does not make every mode equal. The question of the most energy efficient transport comes down to a single measure — how much electricity it takes to move one person one kilometre — and on that yardstick the electric bike, the electric train and the electric car are separated by more than an order of magnitude.

Measured in watt-hours per passenger-kilometre (Wh/p-km), the ranking is consistent across independent studies. At typical real-world occupancy an e-bike uses about 10 Wh, an electric train about 50 Wh, and an electric car about 130 Wh to carry one passenger one kilometre. The e-bike is therefore roughly five times more efficient than a train and more than ten times more efficient than a car for the same trip.

The reason is mass. An e-bike weighs around 25 kg and carries one rider, so almost all the energy goes into moving the person. A car weighs 30 to 80 times as much as its occupant, and most of the electricity is spent hauling the vehicle rather than the passenger. A train sits in between: it is heavy, but shared across dozens or hundreds of travellers, its energy per passenger km falls sharply once the seats fill.

How the energy per passenger km was measured

To compare fairly, every figure is expressed at the same point — electricity drawn from the plug, per passenger, per kilometre — and includes about 10% charging losses. That keeps the units consistent and avoids mixing vehicle-level and passenger-level numbers, which is where most misleading comparisons go wrong.

An electric car draws roughly 190 Wh per vehicle-kilometre at the socket for a typical mid-size model. Divide by the average car occupancy — about 1.5 people in the UK and much of the EU — and the figure falls to around 130 Wh per passenger-km. A train's headline draw is far larger, but spread across a full carriage it lands near 30 Wh per passenger-km when the seats are full, rising to about 50 Wh at the load factors seen in normal service.

Why the e-bike wins on e-bike energy use

The decisive figure in any comparison of e-bike energy use is how little the machine asks of its battery. Pedal-assist bikes typically consume between 5 and 20 Wh/km, with about 10 Wh/km a reasonable average across terrain and rider weight. A common 500 Wh battery therefore covers 50 to 100 km on a charge. Because the rider supplies part of the propulsion and the vehicle itself is light, the e-bike moves a person for roughly the energy a car spends idling at a set of lights.

An e-bike carries a person for about 10 Wh per kilometre — close to a tenth of what an electric car needs once you count who is actually in the vehicle.

Electric train vs electric car efficiency

The electric train vs electric car efficiency gap is really an occupancy story. A single-occupant electric car uses the full ~190 Wh per kilometre to move one person, which is worse than a lightly loaded train. Fill the same car with four or five people and its energy per passenger km drops below 50 Wh, rivalling or beating rail. But cars are rarely full: at the observed average of about 1.5 occupants, the train keeps a clear two-to-three-fold advantage on energy per passenger km. Rail also recovers energy through regenerative braking and runs on steel wheels with very low rolling resistance, which helps it stay efficient even on longer, faster services.

What this means for choosing a mode

• For short urban trips, the e-bike is the most energy efficient transport by a wide margin — and usually the fastest door to door.
• For medium and long distances, a well-used electric train is the efficient backbone; see the related look at high-speed rail versus flying.
• An electric car is most defensible when it is shared: carpooling two to four people transforms its per-passenger figure.
• Efficiency is not the same as carbon. A clean grid narrows the emissions gap, but the energy ranking above holds regardless of where the electricity comes from.

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