RE: Efficiency2 Nov 2018 11:27
It comes down to the energy density per kg, speed of charge, cost and the lifespan of batteries. If we cannot create a battery that is cheap enough and uses materials we actually have access to and does not destroy those materials, charges quickly enough with enough range to make semi spontaneous practical, whilst being small enough in terms of size and weight to be practical, then we need an alternative. This would be some kind of liquid energy store so it can be replaced quickly, solving both the speed and range problems. Tesla has shown it can just about be done, in terms of size, weight, speed of charge and range, but is the solution sustainable and have longevity? Further development will solve the first 4 conditions better, but the 5th remains.
On the other hand fuel cells suffer from rare materials too.
For some vehicles, long range trucks fit example, the charging time will be too long, whilst a car might get to 80pct in 30mins, a truck with 10x the capacity would take 6 hours, or a dedicated power station, here the speed of charge constraint has not been met. Ditto with buses etc, anything hauling a lot of weight, needs a lot of power therefore has extreme charge times. Anything with a variable weight would Benefit from the flexibility that it offers, imagine running out of charge, a truck pulls up to refuel you, much easier than one trying to recharge you.