Sixty years and a few days ago (on 31 August, 1955), William G. Cobb from General Motors demonstrated the first solar car – Sunmobile, a 15-inch-long balsa-wood model car powered by selenium solar cells (photo above).
At the time, General Motors stated that full-size solar cars were impossible, because “even 100-percent-efficient cells could produce only 12 hp. [9 kW] for the average car.” That’s a reasonable calculation: at 100% efficiency, we can expect about 1 kW per m2 of solar panels. Tokai’s 6 m2 solar panels (23.2% efficient) produce about 1.4kW. However, General Motors completely failed to predict modern solar cars like Stella Lux – largely, I suspect, from not anticipating modern composite materials like carbon fibre. Stella Lux (picture below by TU Eindhoven / Bart van Overbeeke) weighs just 375 kg; the 1955 Chevrolet was light for its time at 1450 kg, and needed its 155 hp [116 kW] engine to haul all that steel around. Aerodynamics has improved a great deal since 1955 as well.