Ford has unveiled plans for a concept hybrid car which is solar-powered by panels on its roof. The Ford C-Max Solar Energi Concept can draw power equal to a four hour battery charge, travelling for up to 21 miles just on electrical power.

The roof features a solar concentrator lens, similar to a magnifying glass, which enhances its ability to absorb solar power. It features sensors which follows the movement of the sun to ensure that the car is charging at an optimum rate. 

In addition to the solar panels, the car has a conventional electrical charging socket so it can top its charge from the grid and a traditional petrol engine as reserve power. It’s expected to drive 100 miles to the gallon.

Currently Ford offers a range of hybrid and electric cars, selling around 85,000 in 2013, including 6,300 of the C-MAX Energi range.

The car will be on display at CES in Las Vegas before it goes into testing to see whether it is a viable product. Research by Ford suggests that in the future, solar power will be responsible for up to three quarters of all trips made by an average user who has a solar-hybrid car.

At the show in Las Vegas, which begins on 7 January, Audi is also expected to showcase a car which uses the Android operating system to run it, a software which is usually used to run smart phones and tablet devices.