Are EVs More Efficient Than Petrol & Diesel Cars?

Rising fuel costs and ongoing geopolitical tensions are accelerating the transition from internal combustion engine (ICE) vehicles to electric vehicles (EVs), with efficiency gains emerging as a central driver of change in transport energy consumption.

Since the escalation of the US and Israel's war in Iran, fuel price volatility has pushed more consumers towards electrified transport.

Data from Bloomberg shows that in March 2026 alone, 206,200 EVs were sold across France, Germany and the UK, marking a 44% increase year-on-year. Other markets are seeing similar momentum, with sales more than doubling in South Korea and reaching 16,000 units in Italy, up 67% compared to the previous year.

Against this backdrop, Energy Digital examines how EV efficiency compares with ICE vehicles from an energy perspective.

Energy conversion and system efficiency

At a fundamental level, EVs and ICE vehicles rely on entirely different energy systems. EVs draw electricity from the grid and convert it into motion via batteries and electric motors, while ICE vehicles depend on combustion processes that release energy through heat.

This distinction has major implications for efficiency. A significant proportion of energy in petrol and diesel vehicles is lost as heat during combustion, limiting how much is ultimately used to move the vehicle.

Jan Rosenow, Professor of Energy and Climate Policy at Oxford University, says: “ICE vehicles waste a whopping 80% of energy in their fuel. EVs are propelled by entirely different mechanisms.

"Energy enters the vehicle as electricity, which directly powers the drivetrain making it three to four times more efficient from a final energy perspective.”

Comparing real-world efficiency

Data from the US Department of Energy (DOE) reinforces the efficiency advantage of EVs within the broader energy system.

EVs convert more than 77% of electrical energy from the grid into power at the wheels, whereas conventional petrol vehicles typically convert only between 12% and 30% of the energy stored in fuel.

Energy losses within EV drivetrains are also significantly lower, at around 15% to 20%, compared with losses of 64% to 75% in gasoline engines.

This means that, from an energy input perspective, EVs deliver substantially more usable output per unit of energy consumed, strengthening their role in reducing overall energy demand in transport.

Regenerative braking and demand optimisation

EVs also benefit from regenerative braking systems, which recover kinetic energy during deceleration and feed it back into the battery. This reduces wasted energy and improves overall system efficiency.

According to the DOE, EV efficiency varies depending on driving conditions. Energy delivered to the wheels ranges from 60% to 66% in urban driving and 71% to 73% on motorways.

When regenerative braking is included, efficiency can exceed 94% in city driving and reach around 77% on highways.

Unlike ICE vehicles, EVs also avoid energy losses from idling, further optimising energy use, particularly in congested urban environments.

Emissions and electricity mix

From an operational perspective, EVs produce zero tailpipe emissions, supporting cleaner urban air and reduced transport-related pollution.

However, their overall emissions profile depends on the energy mix used for electricity generation, as well as emissions associated with manufacturing, particularly battery production.

Even when accounting for these factors, the US Environmental Protection Agency finds that EVs typically generate lower greenhouse gas emissions than new petrol vehicles.

Efforts to decarbonise electricity grids and scale battery recycling are expected to further strengthen these benefits. Initiatives from companies such as BMW and Renault highlight growing momentum in recovering materials and reducing lifecycle emissions.