Volvo's hoping to add a spark to next week's Frankfurt motor show with this ReCharge Concept, a C30 hybrid that can be plugged into the mains.Volvo says the ReCharge can be driven up to 62 miles on electricity alone thanks to lithium-polymer batteries that power four electric motors, one for each wheel.The battery takes three hours to fully charge when plugged into the mains, or it can be charged using the car's 1.6-litre flexi-fuel combustion engine.That's not where the technical wizardry ends. The ReCharge is known as a 'series hybrid', which means that there is no mechanical link between the combustion engine and the wheels. Instead, the petrol engine is used only to charge the batteries that power the electric motors. This effectively means that the C30 ReCharge is always powered by electricity, even when the battery is being charged by the engine, which can run off any mix of ethanol E85 or petrol.Volvo claims 45mpg as a realistic economy figure when running on petrol for long periods of time. You can even choose which power source to use. The engine automatically kicks in when 70 per cent of the battery's charge has been used, or the driver can switch the engine on at any point if they want to top up the battery. Volvo won't say when the ReCharge powertrain might be production-ready, but in the current social climate, a hybrid this efficient can't come too soon for Volvo.