Sometimes people see the solar panel on my trike and say something about wanting a #solar car. Let me just run the numbers here, just off the top of my head:

My #ebike - a big cargo tricycle - weighs a few hundred pounds (including me and whatever I'm carrying) and travels 10-15mph. I can go around 50 miles/day if it's sunny, and maintain a steady charge entirely from solar power.

A car probably weighs about 10x that and travels an average of 4x as fast.

Also, I usually provide around 50% of my trike's power by pedaling, which you don't get in a car.

So you'll need 10x4x2x the amount of solar panels I have on the trike to keep your car going at normal car speeds for 50 miles per day, which means 80x the solar panel area I have on the trike. If you only need to go 25 miles most days, you could get away with 40x the solar panels.

My trike's solar panel is about 3x4 feet (12sqft). Our hypothetical solar car is going to need between 480 and 960sqft of solar panels. At about 6 feet wide for an average car, that means your car needs to be 80 to 160 feet long. The average car is around 15 feet long. Our hypothetical solar car could be half the length of some city blocks.

Carrying enough solar panels to keep a car charged is somewhere between "difficult engineering challenge" and "downright absurd".

This isn't just about the implausibility of solar cars; it's about the absurdity of car design in general. Cars use an enormous amount of power for what they do. Electric cars may be an improvement over gas cars, but they are still incredibly inefficient.

This is (part of) why we need safe #bicycle and #pedestrian routes, why we need good #transit, why we need all kinds of #micromobility and #activetransportation.

(I say "part of" because here's a whole other essay to write about the *safety* of a vehicle that's so heavy and so fast, but I'll save it for another day.)