Ford will debut a solar-powered electric car at the Consumer Electronics Show next week.
The car, a concept vehicle not ready for dealer showrooms, is a version of the C-Max Energi plug-in car already sold by Ford (F, Fortune 500). Like the C-Max Energi, the new C-Max Solar Energi can go 21 miles on electricity between charges. It then can switch over and run on gasoline until it is recharged. The concept car’s roof is covered with a solar cells provided by SunPower Corp (SPWR). But because it takes awhile to charge, Ford has also teamed with Georgia Tech to offer a special car port for charging.
Ford calls it an “off-vehicle solar concentrator” — essentially, a magnifying glass that can track the sun as it moves across the sky. The car port boosts the power that can be collected from sunlight by a factor of eight, according to Ford, allowing a full 8 kilowatt charge over the course of a day. The glass was originally designed for a lighthouse.
Ford said its internal data show that the sun could power up to 75% of all trips made by an average driver. It estimates that the solar C-Max could reduce the annual greenhouse gas emissions a typical owner would produce by four metric tons. However, this time Ford is looking to harness all that free energy the sun is producing every day in a plug-in hybrid.
The Ford C-Max Solar Energi has 1.5 square meters of solar panels on the roof that can juice up the battery while it’s parked outside. It’s not as simple as bolting some photovoltaic solar cells to the roof of the car, though. Like other plug-in hybrids, the C-Max Solar Energi has both gas and electric motors. Its total range is impressive at 621 miles, which includes 21 miles of all-electric driving. If the sun is unavailable, you can attach the C-Max Solar Energi to the grid like other electric vehicles. The new concepts and ideas come into play when you’ve got a clear view of the sky.
The solar panels on the roof of the Solar Energi were designed and manufactured by California-based SunPower. These solar cells are a bit different than the cells produced elsewhere. There is a single metal layer on the back of the cell that supports the silicon photovoltaics. It’s a flexible design, which is utilized in the curved glass housing on the top of the car. SunPower also claims its cells can harvest 50% more energy over the same surface area than conventional cells.
For all the supposed efficiencies of these solar cells, 1.5 square meters just isn’t enough surface area to power a car for very long. The C-Max Solar Energi makes use of a special Fresnel lens canopy positioned above the car to boost solar exposure several times over.
A Fresnel lens is a type of compact lens originally developed for use in lighthouses that acts as a magnifying glass. This is not fragile either, Frensel lenses are usually made from plastics like acrylic, so they are light and durable while also being cheap to make. When parked under the Fresnel lens canopy, the C-Max Solar Energi will track the sun and roll slowly backward or forward to keep the most intense area of solar energy concentrated on the panels.
Ford says that using this system the car can gain the equivalent of a four-hour plug-in charge (about 8 kilowatts) over the course of the day. For many people, that’s enough to commute or run some errands without using gas or plugging into the grid. Without the overhead canopy of lenses, the C-Max pulls in too little power to justify putting solar panels on the car in the first place. What Ford is proposing here is a combination of vehicle technology and infrastructure, making it possible to go further between plug ins.
We’re already seeing the expansion of electric car charging stations for electric vehicles, and a Fresnel lens canopy is a lot cheaper. The Ford C-Max Solar Energi will be tested in the real world after CES to see if the technology is feasible to bring to market, it looks very promising so far, the dream of a vehicle powered by renewable energy is one step closer.