The direct solar-powered car is something of a Holy Grail. A car that can charge itself by just being out in the sun would solve several key objections to EVs: They could potentially never use electricity generated by fossil fuels, living up to the “Zero Emissions” label. And they would make owning an EV without a home charger significantly more feasible, as in apartment dwellers.
Despite common assumptions that car solar panels are essentially useless except to run a ventilation fan to cool down the interior (actually a pretty handy feature), there are two current cars (Prius Prime, Hyundai Sonata HEV) whose solar roofs can add up to 2.2 miles of range per day as well as run the a/c. But that’s just a modest starting point. The Sono Motors Sion (top) goes into production next year in Europe, and its solar panel skin can generate up to 21 miles of range per day. And Toyota has shown a Prius Prime (bottom right) with advanced cells that can add 35 miles. And the ultra-efficient but ultra-expensive Lightyear (bottom left) has some 450 miles of total range, augmented by its solar roof which can add 12 miles.
Of the three, the Sion speaks to me: it’s real, minimalist, affordable, practical, small but roomy, and designed for easy DIY repair; a Sion to replace my Scion?
I’m going to focus on the Sion, not only for the reasons given above, but also because it’s actually going into production late next year. Sono was started by a couple of Germans in 2016; they’ve come a long way since then. And how is it being financed? By crowdsourcing, which just exceeded its €50 million goal in 50 days in order to put it in production.
The Sion is a small and tall EV with embedded flexible polymer solar cells all over its body. In essence, they are the car’s skin, and as such, they’re some 20% lighter than comparable steel panels. In order for them to generate a meaningful contribution to range, the Sion is maximized for efficiency rather than fast acceleration or high speeds (140 kmh/87 mph max). Its battery has a maximum capacity of 35 kWh, which is modest by American EV standards, but then the Sion is clearly targeted for different conditions in Europe, where longer ranges are not considered nearly as important. The stated range is 160 miles/255 km on the European WLTP standard. But then of course it starts adding range as the sun kicks in, up to 21 miles.
Before you pooh-pooh that range, remember that’s what you start with every morning. The average American drives 29 miles per day. No, it’s not going to be for road warriors, but it would be more than enough for most typical commuters.
The 248 solar cells can generate up to 34 km/21 miles per day, in Munich, Germany, for example. This is equal to some 5,800 km/3600 miles per year. The chart above shows the variable amounts based on conditions. Undoubtedly this would be better in a sunnier Southern climate, as Germany is not exactly optimal for solar.
An 80% charge at a high speed charger takes some 30 minutes.
The Sion has a sleek, understated interior. If you’re wondering what that green stuff is, it was solar powered too.
It’s called breSono, a natural moss-based air filter that’s conveniently shown under a clear plastic cover to remind you that you’re driving a really green car. And one whose production will be 100% carbon-neutral.
Rather than try to produce the cars itself, final production is being outsourced to NEVS, the company that took over the former Saab plant in Trollhätten, Sweden. Thanks to the Sion’s black polymer skin, there’s no need for a big paint shop or stamping plant. Any color you want, as long as it’s…solar cells. And Sono is working with various suppliers to provide the bulk of the components, keeping their own development costs very low.
The first Sions are expected to roll off the lines in late 2021, and deliveries start in early 2022. Given that Sono has achieved its crowdsourcing goals, presumably this is not all just hot air.
One of the aspects that intrigued me is that the Sion is designed to be as simple as possible for user repairs of standard replacement parts. DIY is back! Obviously, Sion will be sold directly without dealers, and this is a way to simplify basic repair issues and/or work with independent mechanics. Major repairs will be outsourced.
Then there’s the price, of course. It’s listed at €25,500, which is roughly $28,000. Since that includes VAT, which is 19% in Germany, a more comparable direct comparison would be $22,680. All of these are before EV incentives/tax credits, which are considerable in Germany (€6,000) and most European countries.
Those prices in dollars are of course hypothetical, as there’s no current plans to bring the Sion to the US. The case for the Sion might be challenging in the US, although undoubtedly it would have appeal to a certain slice of the market. If it takes off in Europe, I suppose it’s possible it might find its way here too, although federalizing it could be a bit of an obstacle..
More details at sonomotors.com.
The Lightyear One is also a European project, from the Netherlands. An offspring of the University of Eindhoven’s winning World Solar Challenge projects, the Lightyear is an exercise in ultimate range (up to 450 miles) through ultra-efficiency. That’s the result of a carbon fiber body, the best aerodynamics of any car on the road, and a solar roof, hood and tail. Those panels can add up to 12 miles of range. It also has four small in-wheel motors.
It’s an interesting project, but its prospects are not good, due to an expected price of some €149,000 ($163,000). That’s just way too expensive. But it gives some idea of possible future solar integration on a handsome shape. More at Lightyear.one
Currently, only two cars offer solar roofs, and with rather limited impact on range. The Prius Prime is available with an optional solar roof in Japan and Europe (not available in the US due to roll-over standards), and addition to running the air conditioner or other accessories, it can add up or 2.2 miles of range per day. Not much actual payback for the roughly $3,000 option.
The Hyundai Sonata hybrid (HEV) is available in Korea with a solar roof. Its addition to range is roughly comparable to the Prius Prime.
But this past summer Toyota showcased a Prius Prime with drastically improved solar capability. The new cells, made by Sharp, are up to 35% efficient, and claimed to generate enough juice to add 35 miles (56 km) of range on a good day. That really starts to change the equation. And of course the Prime still has its gas-hybrid drive train, so it would be ideal for someone who has no access to any grid charging and wants zero range anxiety.
Something like the solar Prius Prime would be perfect for Stephanie, as almost all her trips are very short, she would be likely to hate/forget to have to plug it in every night, and it would take her on her several trips to the Bay Area per year with zero stops for gas, as it has a whopping 640 mile (electric + gas) range.
Production outlook for the Prime Solar is unknown; it’s obviously an advanced technology concept for now. I’m pretty convinced we’re going to see something like it before too long; it just makes too much sense. Never plug in, almost never buy gas. What’s not to like? And what’s next; self-driving cars?