Many of us who are interested in electric vehicles and solar power have probably wondered if this form of clean electricity could be integrated into an EV somehow. In fact, for some years now, there have been a number of solar-powered car races conducted. However, these vehicles, though impressive in their engineering and abilities, do not meet consumer expectations for speed, comfort, safety, passenger capacity, and storage space.
In a word, they are impractical and not “there” yet in terms of what most of us would find acceptable or even desirable. Also, they could probably not be made street legal in their current incarnations. Finally, they simply have a very odd appearance resembling a narrow waffle with a bulbous area for the driver to see out of, for the single passenger versions. There is a cruiser class for some of these competitions and these vehicles can transport multiple passengers. However, the larger ones still are not road-worthy for normal driving conditions on city streets and are far too slow for freeways and highways.
Of available commercial vehicles, the Toyota Prius Prime in Japan has a rooftop solar power option, but it doesn’t generate that much electricity, perhaps enough to add about 3.8 miles of driving distance to the vehicle’s batteries when there is adequate sunlight.
There has been some speculation about what a small solar power system on the Karma Revero might be capable of, but a writer summarize the numbers he collected and emphasize how little the panel provided: “So, again, about a month. A month of non-stop solar charging, to get you a full battery, which Karma says will take you a whole 50 miles.”
Sono Motors has developed an EV called the Sion, which has more solar cells embedded into its body — about 81 square feet of its surface. It does meet basic consumer expectations in terms of the conventional form and finish, but the extra dimension of having some solar power is intriguing. The range per charge is about 155 miles, and the solar power system has been estimated to have the capacity to add approximately 18–19 miles of electricity per day in order to recharge the battery when there is adequate sunlight.
The fact that this startup accomplished what it did is impressive, and when Sono vehicles are operating in the consumer world, their very presence will turn some heads and demonstrate that such a technology is indeed possible. The amount of electricity the Sono EV rooftop solar power system will generate won’t be that much, but it is a step further than companies have gone before.
One problem with putting solar cells on cars is that there simply isn’t enough surface area. A small collection of solar cells can’t generate nearly enough electricity to function as a primary source.
Even if solar cells can eventually be made that have two times greater efficiency, solar cells on cars would still not generate enough electricity to be the main source. They will be helpful in situations where an EV is going to sit outdoors in sunshine where there are no chargers, but solar power on car bodies will play an auxiliary role for quite a long time to come perhaps indefinitely.
Aside from simple limitations in efficiency and cost of solar panels, remember that cars often park in the shade, are often shaded by buildings even when they are in daylight, and can rather easily get into accidents which could mean the destruction of highly valuable solar technology.
A more practical approach is to put solar panels on your roof or carport and charge your car there. The good news is, that’s what 28–42% of electric car drivers do, according to our research, or 32% according to more recent research. Collecting solar energy on stationary roofs and using that electricity to charge competitive electric cars makes a lot of sense, so let’s hope a lot more people go that route in the coming years er, months … er, days.