More manufacturers are now introducing mild hybrids, which is a way of marginally improving running costs and lowering CO2, but at a relatively small expense. There are various types available, but the most common feature is a small additional battery, a 48-volt electric motor and an integrated starter-generator, which has a dual purpose as a starter motor and a power source to help the engine.\rMild hybrids can often turn the engine off when coasting but struggle to run for any real distance on electricity.