On Tue, 17 Jul 2018 11:50:18 +0100
The Other Mike wrote:
On Mon, 16 Jul 2018 08:59:01 +0000 (UTC), wrote:
It seems to me the whole charging problem of mass ownership of electric cars
has been kicked into the long grass. As usual politicians will only react
when
they have to when the load on the grid either local or national becomes
critical
whereupon headless chicken mode will be engaged.
We've already been here before and there is NO problem.
The additonal supply requirements are negligible if you take your head out of
the sand, forget this idea of a two minute charge because thats how long it
takes for your hydrocarbon car to refuel to do 600 miles to the back end of
nowhere without stopping for urinating or whatever and realise the average car
is, with absolute certainty, sat doing absolutely nothing but depreciating for
many thousands of hours a year. Around half of that almost certainly at home.
So what? Its the energy that it uses when it is moving thats the issue.
When I last commuted to work by car it was a round trip of about 40 miles, say
2 gallons of diesel which is approx 300 million joules of energy. Assuming
for ease of calculation my car is around 33% efficient that'll be 100M joules
used for moving. Electric cars are (according to google) around 50-60%
efficient from grid to wheel so say an electric car needed 200M to do the
same job. With a 30 amp supply that'll take 200,000,000 / (240 * 30) = 27777
seconds = 7.7 hours to charge.
Now I don't know about you, but I suspect an extra 240 * 30 = 7.2KW load
multiplied by however many houses have electric cars multiplied by 7 hours
will be quite a bit extra for the local substation to cope with.