On 16/10/2012 23:57, The Other Mike wrote:
On Tue, 16 Oct 2012 00:14:26 +0100, "Doctor Drivel"
wrote:

SteveW wrote:

Pure electric vehicles
cannot (may never?) have the energy density and rapid refill times of
the "old" technology.

That is pure nonsense.


Petrol is around 34MJ per litre. A 50 litre refuel takes around 2 minutes

So that is 1700MJ transferred in 2 minutes

1MJ = 0.28 kWh

Or around 476kWh of energy transferred from the petrol station storage tank to
the car fuel tank in 2 minutes

Or, using a nominal 240v single phase power source, some 152 hours of charge via
a 13A socket (assuming 100% efficient charging)

476000W / volts = amps

Assume a 'fast' charger running at 1kV and to get 2 minute refuel times the
single phase current is 476A

A 500A connector at 1kV is going to be so large as to be inpractacal, so lets up
the voltage to 10kV and its just a piddling 50A and almost practical.

But then again, that one 50 litre refuel of petrol is equivalent to the output
of a 15MW power station for 2 minutes

Extrapolate that to the entire UK usage of petrol per day - 61.38 million
litres*

A 100% electric fleet needing that level of 'refuellling' requires 584GWh of
energy transfer every day.

Take that over 24 hours and that is around 24GW, all day every day of the year.

Or around the current summer base load.

You have gone an done it now, you have used numbers. Dribble will just
have to call you a name and let that teach you!


--
Cheers,

John.

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