Raphael Thys
A handful of entrepreneurs think solar-powered cars are poised for their day in the sun.
Lightyear, a startup in the Netherlands, is developing a four-door car whose solar cells can generate enough electricity to power brief outings after a day of sitting in the sun. While the company’s Lightyear One resembles a conventional sedan, Aptera Motors Corp. of San Diego is taking another route. It is stretching the traditional image of a passenger vehicle by developing a two-seater featuring three wheels and a dolphin-shaped body.
These and other solar-power vehicles now in development are the descendants of spindly, solar-powered contraptions that gear heads from around the globe have been racing across the Australian Outback for decades. All feature on their exteriors solar cells that work much like the larger solar panels seen along roads and on residential rooftops, converting sunlight into electricity and storing it in an onboard battery pack.
But because their small surface area limits the amount of electricity they produce, solar-powered vehicles need to use energy far more efficiently than most cars on the road today. And the cars being designed for everyday use will come with plug-in capability so motorists can get where they need to go when solar power alone isn’t enough.
Different designs
The first-generation Lightyear One features roughly 50 square feet of solar cells, with a lightweight electric motor located in each of its four wheels. The design dispenses with the gears that more conventional electric vehicles use to deliver torque to the wheels from a centrally mounted motor, helping to minimize weight and extend range.
With its battery pack fully charged from sunlight or power from the grid, the Lightyear One has a range of more than 440 miles, according to Lightyear. After one day in the sun, the car’s solar cells alone would harness enough energy for up to 43 miles, says Lex Hoefsloot, Lightyear’s chief executive. “You only have to charge for the really long trips," he says.
The Lighyear One is slated to go into production next year and would be sold in Europe for roughly $175,000—a hefty price thanks to energy efficiency measures, such as the in-wheel motors. More than 160 vehicles have been reserved, most of them paid for upfront, Lightyear says. The company aims to bring a more affordable model to the U.S. in 2025.
Aptera is planning several versions of its swoopy-looking two-seater, which, according to simulations described by the company, will be good for 250 to 1,000 miles on a single charge, depending on the size of the battery pack. A souped-up version of the vehicle is expected to come with roughly 24 square feet of solar cells, providing up to an estimated 40 miles worth of juice after a full summer day in the sun—and less if it’s cloudy or wintertime, Aptera says.
“Our focus from the beginning was, OK, if range is what’s selling electric vehicles, then how do we maximize that?" says Steve Fambro, Aptera’s co-chief executive. The company says it plans to begin delivering a 400-mile-range version of the vehicle to U.S. customers next year, with prices starting at $29,800.
Another Dutch startup, Squad Mobility BV, is aiming for a more affordable solar-powered vehicle: a golf-cart-size two-seater whose 62-mile range, estimated based on simulations, and maximum speed of about 28 miles an hour make it suited mostly for short trips on surface roads. Four hours in the sun would provide enough oomph to power the vehicle for about 12 miles, says Squad Mobility Chief Executive Robert Hoevers.
“Most of the mobility needs are all of the little trips from the house," Mr. Hoevers says, adding that he expects the vehicles to be used mainly by ride-sharing platforms. Plans call for vehicle deliveries to begin in 2023 in the company’s home market. Prices are set to start under $7,000.
A history of experiments
The vision of sun-powered transportation dates back at least to 1955, when General Motors Co. displayed a 15-inch toy car outfitted with solar cells at a Chicago trade show. Nearly three decades later, two men teamed up to drive an oddly shaped solar-powered vehicle from Perth to Sydney, according to the National Museum of Australia. The low-slung “bathtub on wheels" averaged about 19 miles an hour, taking nearly three weeks to complete the roughly 2,500-mile journey.
Within a few years, solar vehicle competitions were cropping up in Australia and other countries. The events captivated generations of engineering students, including several who went on to become early employees at Tesla.
Traditional auto makers have been experimenting with solar cells for years. Toyota Motor Corp., for example, sells in Europe and Japan a solar-panel-equipped version of its Prius plug-in hybrid. But those cells are only good for a couple of miles a day, according to the company.
The National Highway Traffic Safety Administration, which regulates auto safety, hasn’t tested any vehicles equipped with solar cells for compliance with federal standards, which auto makers self-certify, a spokeswoman says.
Fans of solar cars emphasize the prospect of free power.
“Particularly if the vehicles become more and more efficient, you really can have a car that for six months of the year you may not need to charge it unless you’re doing a larger trip," says Bonna Newman, a senior scientist at the Netherlands Organisation for Applied Scientific Research (TNO) and co-founder of the Alliance for Solar Mobility.
That vision likely will take years to realize, but existing technology can help owners of electric vehicles reduce their reliance on charging stations, Dr. Newman says. She points to a recent TNO simulation showing that adding solar cells to a Renault Zoe electric vehicle used for a weekday round-trip commute of around 25 miles in Munich could cut the need for plug-in charging sessions by roughly 15%. More broadly, efficiency improvements could help make electric vehicles more affordable and less taxing on the energy grid.
Private companies developing solar vehicles have raised roughly $117 million this year through October, up from less than $1 million five years earlier, according to data provided by PitchBook. Sono Group NV, a Munich-based company that is developing a solar-powered car, filed publicly last month for an initial public offering in the U.S. Sono declined to comment.
Cloudy days ahead
Others have expressed doubts about the vehicles, including Tesla Chief Executive Elon Musk. “The least efficient place to put solar is on the car," he said in 2017, noting that many people park indoors and cars have limited sun-facing surface area. In 2019, however, Mr. Musk said the company’s Cybertruck pickup would come with integrated solar cells as an option.
Commercializing vehicles that run consistently on solar power remains a daunting challenge. People still need to get to work, run errands or take longer excursions even if they live in areas with harsh weather or cities where tall buildings cast deep shadows.
Sam Abuelsamid, an analyst at Guidehouse Insights, says he is skeptical that people will routinely get anywhere near the amount of juice from solar cells that some companies are advertising. “There’s a huge gap between theoretical and real-world use," he says.
Dan Steingart, an associate professor in Columbia University’s department of earth and environmental engineering, says that solar vehicles could become more practical, at least for city dwellers, if technological advances enable them to get about 10 miles of range from an hour of sunlight.
“In this urban context, that’s enough," Dr. Steingart says.
Some electric-vehicle enthusiasts are keen to go solar. Neil Mazer, a Tesla owner in Temecula, Calif., learned about Aptera earlier this year from a YouTube video and was captivated by the idea of being less dependent on the electrical grid. He says he invested around $5,000 in the company and put down an additional $100 to reserve an Aptera, adding, “I just like the idea of not even having to really worry about plugging in."