A plug-in hybrid car sounds like an excellent way of squaring the circle between the green cred of an electric car and the range and reliability of one that runs on petrol, but what if you live somewhere that’s a bit off the grid? Ford’s answer is its C-Max Solar Energi Concept, which makes its debut at CES next week. The car uses a combination of high-efficiency solar panels and a separate frame roofed with a Fresnel lens to concentrate sunlight on the panels to give it a proper charge without using the engine or plugging into the electrical mains.

Called a “first-of-its-kind sun-powered vehicle” by Ford, the C-Max Solar Energi Concept is a joint project designed in collaboration with California-based SunPower Corp. and the Georgia Institute of Technology. Ford sees the concept as not only a technology showcase, but as a demonstration that photovoltaics are emerging as an economically viable source of power.

The key to the C-Max Solar Energi Concept is its roof, which is covered with 1.5 sq m (16.1 sq ft) of photovoltaic cells designed by SunPower. The cells have a metal backing for greater support and the silica cells are much thinner than conventional solar cells, making them stronger and more flexible, which allows the glassed-in top of the concept to maintain a streamlined curve.

Ford says that the solar cells harvest 50 percent more energy than conventional cells, however, as this isn't enough to charge the concept, Georgia Tech designed a sort of car port with the flat roof made from acrylic Fresnel lenses that concentrate the sun's rays onto the top of the car. The clever bit is that the system tracks the sun to keep it concentrated on the panels for maximum effect.

According to the company, the charging system generates the equivalent of a four-hour mains charge (8 kW). Ford claims that the concept boasts the same 620 mile (998 km) range as its C-MAX Energi, with 21 mi (33.7 km) on electricity alone.

Ford estimates that the solar power hybrid would reduce a typical owner’s carbon dioxide emissions by four tonnes (4.4 tons) and would be useful for areas where the driver lives off the grid or where electricity supplies are unreliable or expensive – though it may not be so great for those of us who live in rainy climates where the sun is a rumor for four months of the year.

Ford says that after being shown at CES, which runs January 7 to 10, the concept will begin testing to determine if the design is feasible for practical applications.

Source: Ford