Know Your EV
Battery Electric Vehicles (BEVs)
Battery electric, or pure electric, vehicles are only ever powered by electricity, meaning zero CO2 emissions at the point of use. The drivetrain usually consists of one or more electric motors, with a large battery pack charged from a conventional plug socket or public charging point.
Pros: BEVs have large benefits for cutting inner-city smog, but are also suited to rural commuting where it can be more convenient to recharge at home than to go to the nearest fuel station. Modern electric powertrains allow performance to rival conventional cars, while recharging costs £2 or less, tax costs are low and the low number of moving parts keeps servicing prices down too.
Cons: Manufacturing long-range batteries is expensive, which means production vehicles typically have a range of up to 100 miles and cost more to buy than a conventional rival. Because the technology is new, uncertainty about longevity is keeping residual values low. Charging takes up to eight hours on a fully depleted battery, which makes them impractical for long journeys, and not all drivers have a suitable charging space outside their home or office.
Examples: Renault Fluence Z.E., Nissan LEAF
Hybrid Electric Vehicles (HEVs)
Hybrids are the most common electric vehicles. These maximise fuel efficiency by using an electric motor to assist an efficient internal combustion engine. Most allow a couple of miles of pure electric motoring, while some newer models can combine the two power sources under heavy acceleration. Others have an electric motor driving the rear wheels, which allows four wheel drive traction without the usual decrease in fuel economy.
Pros: Hybrids have been on sale for over a decade, so this is now a proven, mainstream technology. There’s also a growing selection of models on sale, including high performance variants, which means lots of choice for drivers no matter what their taste or needs. It’s also easy to get used to, with conventional refuelling times and a driving experience familiar to anyone used to an automatic gearbox.
Cons: The technology is still expensive, so many hybrids are priced higher than an efficient diesel. Premium brand models tend to be targeted at the US market, where the focus is on improving air quality rather than reducing CO2 emissions, and these have large petrol engines. In Europe, where tax is largely CO2-based, the savings don’t always add up even for hybrids with small engines.
Examples: Toyota Prius, Peugeot 3008 HYbrid4
Plug-in Hybrid Electric Vehicles (PHEVs)
Plug-in hybrids have an internal combustion engine and electric motor, but with the option to charge the battery from an electrical socket. This allows them to cover short-range commuting on electricity alone, switching to a conventional hybrid setup when the battery range is exhausted. Mainstream models are due to go on sale in the UK in 2012.
Pros: Plug-in hybrids are an extension of familiar technology, simply adding longer range electric mobility and lower tax costs to their abilities. These vehicles can cater for most short journeys without any point-of-use emissions, which makes them useful for reducing inner-city smog, yet have conventional refuelling times for long journeys.
Cons: Despite high claims of staggeringly fuel economy, the efficiency of plug-in hybrids are vary dramatically based on usage. Drivers mostly covering short distances will hardly ever use any fuel, while those who frequently use the car for long journeys will struggle to come close to the economy figures touted by manufacturers.
Examples: Volvo V60 Plug-in Hybrid, Toyota Prius Plug-in Hybrid
Extended-Range Electric Vehicles (E-REVs)
Although extended-range electric vehicles have both electric and internal combustion power sources, they function differently to a plug-in hybrid. For journeys up to 50 miles, the car travels on electricity alone, recharged using a charging point or electrical socket. Once the electric range is exhausted, the engine is used to drive a generator, maintaining battery charge and providing an indirect power boost at high speeds. Unlike a hybrid, this never directly turns the car’s wheels.
Pros: E-REVs provide a useful electric range, allowing urban commuters to cover short distances without using any fuel but without needing a second car for long journeys. This technology also allows these vehicles to return low fuel consumption and CO2 emissions figures, which gives tax advantages for business users.
Cons: Although E-REVs can cover long mileage, they offer the biggest cost savings when used for short journeys where the range extender is inactive.
Examples: Chevrolet Volt, Vauxhall/Opel Ampera
Fuel Cell Electric Vehicles (FCEVs)
Fuel cell vehicles use a reaction of hydrogen and oxygen to produce electricity, which in turn powers an electric drivetrain. Refuelling takes around three minutes and the only tailpipe emission is water vapour. Although there are manufacturer trials going on across the world, no fuel cell vehicles are available for sale, but several are expected to go on sale within the next five years.
Pros: Fuel cell vehicles offer the convenience of conventional powertrains, such as long range cruising and short refuelling times, while emitting no harmful gases in use.
Cons: The refuelling infrastructure for hydrogen fuel cell vehicles is almost non-existent in the UK, with only one station available to the public. For the technology to take off, it will need substantial investment in a nationwide network of hydrogen refuelling stations.
Examples: Honda FCX Clarity, Opel Hydrogen4