Hayden Smith and his racing team are euphoric. They had spent the last weekend of July obliterating a world speed record that had stood for more than a quarter of a century. Once certified, the Sunswift eVe, built by students hailing from Australia’s University of New South Wales will reign as the fastest electric car to cover 500 kilometers (310 miles). More importantly, the achievement brings it one step closer towards becoming the world’s first street-legal solar-powered car.
The eVe debuted last year at the biannual World Solar Challenge, an event where scores of automotive engineers — hailing from some of the finest research institutions around — take part in a grueling long-distance race through the heart of the Outback. As the premier spectacle in solar-powered motor racing, the cross-country course runs from Darwin, located at the top of the continent, all the way down to Adelaide at the southern tip, a total distance of 1,877 miles.
Since the inaugural race in 1987, the gathering has also given rise to a number of impressive achievements. For instance, the Sunswift team, a longtime participant, built an earlier model that, at an average speed of 55 mph, holds the title of fastest solar-powered vehicle. But even at a glance, it’s easy to see why many say the technology still has a ways to go before making the grade as a serviceable means of transport.
With wide, flat tablet-shaped frames, they’re more reminiscent of a giant tic-tac on bicycle wheels than anything resembling conventional automobiles. The driver’s cockpit, meanwhile, is little more than oval pod that starts to feel cramped, just by looking at it. This approach, however, allows teams to reduce weight and drag through aerodynamics while expanding the amount of surface area that can be decked out with solar cells. In essence, the event has become more of showcase for entries more akin to drivable solar panels than actual cars.
All that changed last year with the addition of a separate “cruiser class” division to accommodate vehicles conceived in the mold of family-style sedans and two-seaters. The idea had been partly inspired by one team’s audacious decision to show up at an event in 2009 with a peculiar entry called the BOcruiser. The car, designed by students from the Bochum University of Applied Sciences in Germany, was rather slow compared to the rest. But it stirred up intrigue amongst on-lookers with a classic four-wheel chassis, ample passenger room and a look nearly indistinguishable from that of a Volkswagen Beetle.
“We probably won’t even arrive on time, but that doesn’t matter,” professor Friedbert Pautzke, of Bochum University of Applied Sciences told the German publication Deutsche Welle at the time. “What we’re really interested in is demonstrating that people can use these rather normal-looking cars to drive across Australia.”
Much has been made of the foreseeable feasibility of bringing a “practical” solar-powered commuter vehicle to the masses. A few years back, Japanese manufacturer Toyota Motors took a crack at integrating solar into its Prius model when they gave buyers the option of an energy-harvesting roof package that generated just enough power to run a ventilation fan during hot days. At the time, the deluxe package, costing $2,000 to $4,000, went on to become somewhat of a subject of ridicule, with detractors pointing out how the net boost from solar cells was so paltry, it simply wouldn’t justify the expense.
In 2012, William F. Banholzer, a chemical engineer and former executive vice president and chief technology officer at the Dow Chemical Company, penned an editorial in Forbes that cited the solar-powered Prius as a classic example as to why a solar-powered car “isn’t practical” and “never will be.” He wrote:
An entire Prius rooftop covered in photovoltaic cells could only generate a tiny fraction of the energy needed to propel the car 33.4 miles — the average distance an American drives in a day.There’s a reason why cars that win the World Solar Challenge are built like small, flat spaceships on bicycle wheels. The roomy sedans and SUVs that we love to drive are simply too massive to be powered by the sun.
In a way, the eVe can be thought of as an ambitious follow-up to the German team’s initial efforts to prove that the very notion of a self-powered car can actually make a lot of sense in the real world. Besides standard seating for two, accompanied by front and side windows, the exterior is comprised of a NASCAR-inspired carbon fiber body that weighs only 661 pounds. Meanwhile, under the hood is a 132-pound Lithium-ion battery, which transfers power to a pair of DC motors installed within the hubs of the rear wheels, a setup that allows for a stated efficiency of 97 percent.
“We take no prisoners when it comes to making sure the car is as efficient as possible,” Smith says. “Everything from the curves in the vehicle, to the tape we use, to the items we have in the car, is designed to keep it as efficient as possible.”
For the record-breaking feat, the car was brought to a racetrack in the southern Australian city of Victoria. The on-board solar panels were turned off for the duration of the run to showcase its capacity for extreme endurance and efficiency. At the course’s end, the team would discover that the driver was able to maintain an average speed of 66 mph, eclipsing the previous speed record of 45 mph by a wide margin.
“Best of all,” Smith added, “we just broke a world record using lower operational power consumption than your typical four-slice toaster.”
To put this in perspective, the eVe consumes less than a third of the electricity at 20 kilowatt-hours when traveling at a cruising speed of 66 mph than the Tesla Model S, which uses fuel at a rate of 67 kilowatt-hours as it moves at a lower speed of 55 mph, according to Smith’s calculations. The caveat, which should be noted, is that the race car isn’t loaded with the kind of standard options that make production models heavier, and consequently, less efficient.
After the victory lap, Smith was sanguine. He feels that the hastening pace of technological advancement, while still having a ways to go, will soon make it possible for photovoltaic cells to serve as a viable range extender as cars become more efficient. Take, for instance, the solar panels on the eVe, which are capable of providing an estimated daily peak power net gain of approximately 800 watts. On a sunny day, this translates to an additional 300 kilometers (186 miles) on top of the car’s 500 kilometer per-charge range.
“A lot of people drive 30-60 minutes to work each day and park in the sun,” he explained. “Using eVe to commute would mean that, on most days, people would never have to recharge.”
Another encouraging sign for the technology may come from the Ford Motor Company, which announced earlier this year that they’ve been prototyping an electric car with a unique rooftop PV system that they claim is capable of providing, on good days, an extra 8 kilowatts of power, roughly the equivalent to four hours of plugged-in charging.
To meet the criteria for road registration by 2015, the Sunswift team plans to carry out a series of minor modifications like installing headlights, raising the vehicle’s height and remodeling the interior. This includes, among other enhancements, adding dashboards, drink holders, a better steering wheel, de-misters, and a wider range of controls for the driver.
“Looking ahead, we’re going to focus on working on refinements like ergonomics, comfort, and convenience,” Smith says. “We want the drivers and passengers to feel like they’re in a real car.”