Vastly reduced fuel consumption can be achieved by hydrid vehicles now under development that have batteries that can be charged by an external electrical source as well as the onboard engine. Such vehicles could give around 40-50 km driving range from an overnight charge alone, sufficient for the majority of routine driving. As the battery runs down, the internal combustion engine would recharge it as is the case with current hybrids. As of 2009, batteries were under development that could be recharged efficiently by both an external source of electricity and by an internal combustion engine coupled to a generator.