Originally Posted by
philehidiot
If you do the calculations then even if you assume EV motors are 95% efficient (they're not most of the time, only when cruising) then the efficiency from the point of release of energy, grid losses and so on means that in terms of energy efficiency they're currently roughly (back of envelope) on a par with internal combustion. Probably, given the gernerous calculations a fair bit less. What you're achieving is moving the emissions away from populated centres to the power station which isn't a bad aim, but we must be honest that this is only helpful in terms of human helath and not for the enviroment. Once you add on the horrific lifecycle of lithium batteries then the net environmental impact is awful. Also when you appreciate the massive leap in efficiency coming with compression ignition engines, EVs are going to be left behind.
This being said, if you don't buy rubbishrubbishrubbishrubbishty Chinese crap there are now solar panels (designed in Germany and made in Italy) which are 78% efficient and if you can use this with a battery system to charge your EV then we're on to a winner.
Just FYI in terms of efficiency calcs the assumptions are based on the following: you have a power station at ~30% efficiency burning hydrocarbons, ~30% of the energy from carbon neutral (wind, nuclear and probably generous if you examine our mix - could be a little more or less as we can't track the source of our electricity bought in from interconnects), ~15% grid losses, ~15% putting energy into and then ~15% extracting from the batter in the EV and then the efficiency of the motor being ~95%. This doesn't look at the variable efficiency of the motor which does drop well below 95% when setting off and so on, it doesn't look at transformation from grid to vehicle and it doesn't look at regenerative braking (which is currently limited to being crap due to the system needing to thermally throttle).
There is a lot of hope for EVs and the tech does need to be developed but there are massive issues regarding the way we create electicity for them and also running costs / servicing are huge limitations. The tech does need to be developed but if I were a punter looking to help the environment and save me money, I'd be waiting for compression ignition engines to come out in 2019, waiting another year for the bugs to be ironed out and buying one in 2020.