On Fri, 15 Jun 2018 11:54:26 -0700, Steve Koerner wrote:

On Friday, June 15, 2018 at 10:39:26 AM UTC-7,
wrote:
On Friday, June 15, 2018 at 12:18:30 PM UTC-4, Steve Koerner wrote:
Go ask your electrical utility for a price quote on that sort of
connection...

Well Moshe, when the supercapacitors become workable in cars, why
wouldn't they also become workable for buffering at the filling
station? Megawatt connections won't be the issue.

You'd need a heck of a lot of those supercapacitors. The reason they
are being talked about in cars is to provide acceleration or
regeneration for a few seconds, a small amount of energy relative to
what's stored in the main battery. Sort of like a now-old-hat "hybrid"
car uses the battery for short-term acceleration and regeneration while
the gasoline tank stores most of the energy. The supercaps have a much
lower energy storage density, and much higher price per energy unit,
relative to batteries. Also, at a "filling station" you'd want to
allow one car to fill-er-up after the other, not much time for
buffering. So you'd still need megawatts of supply. That's actually
perhaps economically feasible at a dedicated filling station, but not
at home.

Makes sense. I've not looked at numbers. It's fun to read the tidbits
in Gliding International about carbon nanotube materials and super dense
battery technology -- even if it's mostly fictional and none of it will
come to light. Numbers just spoil the fun. I'd rather continue to
contemplate supercapacitors that will be tiny and cheap and hold
enormous energy.

A very quick bit of playing with numbers (service station with 18
chargers, assuming that each recharge was the equivalent of a tankful of
petrol, 60 litres, and charging averages one full charge sold per charger
each hour over a 10 hour day) looked like an equivalent electric charge
point would need a continuous power input of around 0.1 MW.

Assumptions:
- 60 litres is a full tank: that's roughly what my Focus takes.
- The standard energy content of a litre petrol is 10 KWh.
- The number of pumps matches my local supermarket.
- The average fill rate of one tankful per pump per hour is a guess
based on how full the service station is at various times combined
with a guestimate that the average stop for a full tank of gas is
10-12 minutes.


--
Martin | martin at
Gregorie | gregorie dot org