Two weeks ago, we looked at the autonomous cars that are being built at the Center for Automotive Research at Stanford (CARS). This week we look at the ultimate in efficient vehicles: solar-powered, extremely aerodynamic cars.
“The first aim that motivates us on an everyday basis is that we’re a racing team, and we’re trying to build the fastest solar-powered vehicle,” explains Nathan Hall-Snyder, team leader at the Stanford Solar Car Project. “But we do a lot of educational outreach…as well as a lot of cutting-edge research: members from our group actually were members of the founding team of Tesla Motors.”
Because solar cars could be the vehicles of the future, the engineers are slowly making some allowances for comfort. “The big focus of [Apogee, the latest-generation car] was switching to the upright driving position,” says Hall-Snyder. “In solar cars you used to lie flat in the car—that was very uncomfortable. So this car was [designed for] research related to an upright, more comfortable car. For our next car, we worked with Lockheed Martin on the aerodynamics—because when you’re cruising on a car like this, about 66-80% of the energy that the motor is using is going toward pushing air out of the way. A car like this, mostly because of aerodynamics, gets the energy equivalent to about 1,400 miles per gallon.”
Efficiency like that wouldn’t be possible without huge advances in materials and technology—solar cars have come along way since Stanford’s first solar car in 1989. Back then, “the cars each had 12 square meters of solar panels, the cars weighed about a thousand pounds, and they only went 20-30 miles an hour,” says Hall-Snyder. “And now we have a car with half that amount of solar area, and it weighs half as much, and they’re going highway speeds. Everything has gotten much better: the panels have gotten more efficient, they’ve gotten smoother, the anti-reflective coat has gotten better. We’re getting to the point where a car like this could start to become practical, as long as you don’t have air conditioning. If you had air conditioning, all bets are off.”
Stanford Solar Car Project blog: http://solarcar.stanford.edu/blog