On Thursday, 18 April 2019 09:33:38 UTC+1, Mike Clarke wrote:
On 17/04/2019 21:35, NY wrote:

Diesel has an energy density of 38.5 MJ/litre. So 60 litres in 5 minutes
(300 seconds) is:

60*38.5/300 MJ/sec = 7.7 MJ/sec, aka 7.7 MW (gulp!)

The filling station at my local Asda has 8 pumps. If we all used
electric cars and didn't change our usage patterns they'd need to be
replaced with 8 super fast recharging points and need a 62 MW power
supply to provide the 5 minute recharge. Scale that up for the whole
country and you have a massive infrastructure problem.

Since electric motors should be much more efficient than internal
combustion engines

With electric the bulk of the losses move to the power station instead. And of course the car has to move more weight, creating more losses.

the above figures are pessimistic but even if the
power requirement was only 30% of the above they'd still be problematic.

A magic new battery that can store far more per kg isn't going to happen any year soon. What options does that leave?
1. not going electric
2. going hybrid
3. going electric with any of
- lots of charging points to enable small battery use
- much lower Cd, which isn't hard to achieve
- in some areas it may be possible to run small vehicle routes as well as large, enabling safe use of golfcart size cars, where electric power works much better
- battery swapping
- charge as you go networks, probably overhead wires
- some new approach to crash safety that permits use of lightweight vehicles

Once you've come up with the possible ways to make electric work, those are the only options.


NT