Hybrid cars and their running costs explained

toyota-prius-plug-in-000.jpg Hybrid cars are advertised as being able to save money for motorists, but is that really the case? Green Car Guide
reports on the typical running costs for a hybrid car.

A hybrid is a vehicle that features a conventional petrol or diesel engine plus an electric motor and battery. The idea is that the petrol or diesel engine provides the power for most of the time, but the electric motor can also assist – in order to save fuel. The electric motor gets its energy from the hybrid system’s battery, and the battery is recharged by the car itself, such as by capturing energy that would otherwise be lost when braking.

Some manufacturers, such as Honda, use ‘mild’ hybrid systems, where the electric motor provides ‘assistance’, but it’s not possible to drive for any distance on electric power alone. This system is relatively cheap, but typically only provides small fuel efficiency gains.

Toyota is probably the best-known manufacturer of ‘full’ hybrids, with the Prius, now in its third-generation, recently taking the accolade of the world’s best-selling car. By 2013, Toyota will have sold over 5 million hybrid vehicles worldwide.

The Toyota ‘full hybrid’ system provides the ability for the car to drive on electric power alone, at low speed and at low load, for up to around one mile. The hybrid system is also constantly working while the car is being driven normally in order to optimise efficiency and fuel economy.

‘Plug-in hybrids’ are now appearing, and Green Car Guide
tips this technology as being one of the key ways for manufacturers to reduce emissions of their vehicles to meet forthcoming EU targets (all car makers need to achieve a fleet average of 95g/km CO2 by 2020). As their name suggests, plug-in hybrids can be ‘plugged in’ to mains electricity in order to recharge their batteries, so providing a longer range, better economy, and lower emissions. The Toyota Prius Plug-in hybrid has a driving range of around 15 miles on electric-only power – and an amazing official fuel economy figure of 134.5mpg.

There are also Extended-Range Electric Vehicles, or E-REVs, such as the Vauxhall Ampera. E-REVs are considered to be similar to hybrids, but in fact they are almost the opposite – whereas a hybrid has its petrol or diesel engine as its main motive power, with support from the electric system, an E-REV is an electric car at all times, with its on-board petrol generator being used as a back-up if the battery becomes depleted. An E-REV such as an Ampera has an electric-only range on its battery of between 35-50 miles.

So do hybrids have lower running costs? The answer should be yes, but it depends on how they are used. A hybrid system performs at its best if the car is used in a ‘stop-start’ urban environment. Under such conditions, the hybrid system gains energy under braking, which can be used to provide power later on, and a hybrid should emit zero-tailpipe emissions for a good proportion of time in an urban environment. This saves fuel, and so cost, for the driver, but it’s also better for local air quality than, for instance, a diesel car that doesn’t have a stop/start system.

Hybrids are more expensive to buy than conventional petrol cars, but if a hybrid emits 100g/km CO2 or less then it will be eligible for certain financial benefits, such as exemption from the London Congestion Charge, which could offset the extra purchase price in around just 12 months. Because hybrids have lower CO2 emissions, they also have lower company car tax benefit in kind rates than comparative non-hybrids. VED, or road tax, will also be lower, or zero, and of course fuel bills will be cheaper.

So if hybrids are used in urban area such as London then they’re likely to be cheaper to run, and to have lower ‘whole-life’ running costs. If a hybrid is primarily used up and down a motorway, it’s likely that an efficient diesel will be cheaper to run.