Extended-range hybrids, such as the Chevrolet Volt and Vauxhall Ampera, are similar to PHEVs but they are always powered by their electric motor. The petrol or diesel engine simply keeps the battery charged on longer journeys. The battery has a range of 40/50 miles, with the petrol engine extending this by a further 330 miles. The engine doesn't power the wheels; instead it provides power to maintain the battery power, so it acts like a generator.

Advantages

• extremely quiet
• zero emissions when driving on batteries
• gearbox free
• easy to drive
• no range anxiety
• cheap to run if doing regular 40/50 mile commutes
• tax efficient

Disadvantages

• expensive
• complex to maintain
• poor charging infrastructure
• battery life concerns
• embedded energy used in battery manufacturing
• resale value uncertainty

See cost per mile calculations

Compare the annual running costs of extended-range hybrid vehicles to conventional diesel and petrol cars.