[IshKebab]

> In the very least, the battery mass is responsible for an effective drop in energy efficiency of around 30% just to cart someone around.

It's not nearly as simple as that because electric cars have regenerative braking, and because the energy doesn't all go into acceleration. A lot (probably most, depending on how you drive) goes into wind/rolling resistance at a constant speed and that doesn't depend much on mass.

[glogla]

Toyota H2V (Mirai) has a small battery that serves as a buffer for the fuel cell, and it can also regen brake into it.

I'm still convinced hydrogen is scam greenwashing natural gas, though.