Solar EVs Are Sneaking Into The Mainstream

For decades, solar-powered vehicles have been a cool challenge for university teams and backyard tinkerers, and occasionally the subject of slapstick comedy. But for serious use as a transportation machine? No way! Recent moves in the industry to make serious solar cars are now getting to the point where even mainstream news sources are picking up on it.

It wasn’t all that long ago that all EVs were given the same ridicule as solar cars. Sure, there were some for sale in California, but they were just city cars, plus they were small and funny looking. While it generally wasn’t true, they also had a reputation among the general public for being slow and weak. Outside of some limited factory EV sales, the only way to get your own EV was to build one in your garage. Unless you wanted to pay $100-200,000 for expensive batteries, you were stuck with a bank of lead-acid batteries that might take your vehicle 20 or 30 miles on a charge.

But, Tesla came along and changed all that. It took the tZero concept‘s basic formula, improved upon it, and built the Tesla Roadster. Not only was it quick, but it had enough range to be seriously considered by most drivers. Plus, it was cool. The Model S proved that an EV could serve as a family sedan, the Model X proved that an EV could be a decent crossover and pull 5,000 pounds, and then the Models 3 and Y proved that EVs could be affordable for the middle class.

Now, nobody questions whether an EV can be a serious car outside of some rural and towing edge cases, because the proof is all there staring them in the face.

The problem for solar cars is that they haven’t been proven the way EVs have in the public eye. Most people think solar cars are about like Wayne Szalinski’s solar van in Honey, I Blew Up The Kid, barely able to get from home to work (plus, a stray cumulonimbus cloud could make you late).

A screenshot from Disney’s Honey, I Blew Up The Kid, showing Wayne Szalinski’s solar-powered van struggle to climb into the parking garage (Fair Use, Commentary).

But solar car technology has been slowly improving out of most people’s sight for decades. The first solar car was actually built in 1955 by GM for a car show. It was just a tiny toy car, but it showed that light from the sun could be used to turn wheels. One of the wheels it turned was in the head of adventurer Hans Tholstrup. Inspired by GM’s solar toy car, he decided to build a car that could actually carry people, and he drove it across Australia.

This led to a series of solar races that are still going to this day. The first race in the late 1980s led GM to build the EV1, and gave a number of other companies a crash course in building EV components. This set of efforts led to Tesla and today’s EVs. While the rest of the industry moved on to grid-powered EVs, the competitions continued. Average speeds and distances traveled daily are steadily increasing.

Most recently, an MIT team managed to get their car across over 1,000 miles in five days, at an average of almost 40 MPH. This isn’t really any better than GM’s Sunraycer did in the ’80s, but keep in mind that the resources available for a school team are far less than what one of the largest automakers in the world could put into the race, so it’s a sign that prices are definitely dropping. The top solar-only speed on solar power alone is 55 MPH, while average race speeds have exceeded 65 MPH.

Those solar racecar numbers don’t sound terribly impressive, but keep in mind that these solar race vehicles are required to only run on solar power, and they’re in a long-distance race. For a normal car, neither of those limitations apply. The average American driver only travels around 26 miles per day, and road trips are uncommon. Even on road trips, a solar car could just plug in and be a normal EV, taking advantage of the same charging infrastructure normal EVs use.

Whether on-board solar panels are useful all depends on efficiency.

First, the efficiency of the solar panels determines how much power the vehicle could generate for itself on a good day. Current commercially-available solar cells are generally about 18-24% efficient, but low-volume experimental cells can exceed 30%. This means that the surface of a car (assuming the windows are covered with cells, too) can produce 500-1000 watts. Over the course of a day in good sun, that means the car can generate 2-4 kWh.

The next question is how efficient the vehicle is. If the car is a pig and only gets 2 miles per kWh, that 4 kWh of charge will only make the car go 8 miles on a whole day of charging. That’s obviously not going to be too useful. But, if you can make a vehicle that can get 10 miles per kWh, it’s possible to do all of your driving on solar power, because the cells can add 40 miles in a day.

If you drive less than what the car generates, that means you’ll accumulate “rollover miles” in the car’s battery every day. So, when a cloudy day comes along, you’ll just do your daily driving on power the car saved up from other days.

While the average person thinks that solar cars aren’t yet viable, a mainstream publication recently took notice of all of the solar cars that are fixing to come out. The Lightyear One and the 2-seater Aptera are both going to get a little over 40 miles of range from the sun daily (in good conditions). Squad Mobility BV is going to make a solar golf cart for neighborhood driving. Sono’s Sion is also going to get useful range from its onboard solar cells.

Even Tesla is planning on offering solar power for the Cybertruck, providing up to 15 miles per day, or more with a folding solar panel arrangement to increase surface area.

While CleanTechnica readers probably already knew about all of this (because both the writers and the readers are eco-nerds around here), mainstream publications taking notice means that solar EVs likely have some real potential to go mainstream.

Once the general public sees that solar EVs (even if they’re “hybrids” that use the grid part-time) are viable and useful for the average driver, we can expect to see them go the same way EVs did after Tesla proved that they’re a good option.

Featured image by Aptera.