My commute would be 16 miles one-way by bike (more distance than by car), all on bike paths except for the first two miles and last four which are on potentially hair-raising roads but nothing awful.
Am I completely insane for hoping a decent e-bike would let me do that in 30~40 minutes? I probably wouldn't consider it if it took longer than that (which is why I've ruled out normal biking, that's definitely not happening at that pace). Are e-bike rentals common? Or do any offer returns? I feel like I'd know 100% the answer after trying it once.
It's not insane to hope for that, but you will need to be realistic about your bike and your route.
BikesMy first ebike was a RadRover, and I averaged about 17 mph on that. While top speed was 20 mph, traffic, stop lights, etc. made an average of 17 about all I could do.
My current ebike is a Haibike xDuro, with a Bosch mid-drive. I put a performance chip in it, so I have no speed limiter, and generally travel at 26-27 mph, with an average commute speed of 24 mph over 18 miles. Best ever was an average speed of 24.9 mph, and I was cranking hard the whole way to work. I have a shower at work.
RouteRoute will make a massive difference in your average speed, and could easily double your ride time from an 'ideal' state. My commute is 15 miles of paved canal trail with very light cycling traffic, no intersections, and no stops. The final 3 miles is on surface streets with bike lanes with the occasional stop light. If I'm really hustling home, I will often clear 30 mph for a mile or two on some sections of my ride.
I have nearly 5,000 miles on ebikes now, nearly all commuting miles. Including a reasonable value on my current bike, my average costs have been about $.13/mile.
The RadRover was fun, but the miles I was putting on it really beat it up quickly. After 1,400 miles I had replaced the front fork, had the wheels trued up several times, replaced the tires, etc. It felt like a lot of maintenance. To be fair, it is a heavy bike with huge tires and I was using it as a long distance commuter. Just not the right tool for the job.
The Haibike I have now has been phenomenal. Quality is excellent, I trust all the components, and with 3,400 miles or so on it I have proven its reliability. I jump off curbs with it, ride at 30 mph frequently with the chipped motor, and generally have a blast of a time on it. I would buy it again in a heartbeat.
Good luck!