This year, the race regulations are a clear sign of how rapidly solar technology is changing. Teams have to use a smaller solar collector than before: cars in the Challenger class can have no more than 43 square feet of solar cells versus nearly 65 square feet for the previous race, in 2015. That’s half the area allowed on cars from the original 1987 race. In other words, technology is advanced enough now (both in solar cells and the underlying vehicle designs) that you don’t need a sea of panels to keep a car running.

Source: Solar car race kicks off 30th anniversary with a fresh challenge