Mike Carrell & I wrote:
You fill a gas tank in avout five minutes with enough energy to
drive a car at 70 mph for several hours -- and you are going to
charge the capacitor with that energy in minutes?
Mike has brought up this important point before, HOWEVER, there are
two mitigating circumstances:
1. Electric cars use far less energy per kilometer of travel than
gasoline cars do.
This is easy to estimate, actually. Electric cars use 0.2 to 0.3
kWh/km. Assume the range is 500 km (310 miles) -- which I suppose is
about average for U.S. gasoline cars, but I wouldn't know. Anyway,
suppose it is . . . and 120 fully discharged cars fill up per hour.
That's 18,000 kWh per hour, or 18 MW.
Looking up Gas Stations & Truck Stops for sale here:
http://www.mergernetwork.com/industries/Gas-Stations-and-Truck-Stops/00002.htm
. . . I find that a lucrative station pumps 160,000 gallons per month
with 12 stations (see lot # BFS-110285). The pump rate is limited to
10 gallons per minute by law, sez the EPA. So that's 13,333 gallons
per pump, or 1,333 minutes of operation per month. There are 43,800
minutes per month, so the duty cycle -- I guess it would be called --
is 3%. The pumps are idle 97% of the time.
If the place is full up for 10 minutes a day, and then each pump is
used a couple times an hour during daylight hour, that would be about 3%.
3% of a day is 43 minutes, so if this were the electric charging
station it would use 12,950 kWh per day. With a bank of
super-capacitors that can spread that demand evenly throughout 12
hours of daylight, it comes to a steady 1.08 MW of power. Or with a
whole bunch of supercapacitors to spread consumption through the
entire 24-hour day it is a steady 500 kW. According to Arthur D.
Little this would place it in range of:
"Hospitals (200-300 beds)
Large Hotels (750 rooms)
Office (200,000 sq. ft.)
School (125,000 sq. ft.)
Large Retail"
"200 kW - 1,000 kW baseload power requirements" See p. 8 here:
http://www.osti.gov/bridge/servlets/purl/475277-moRBKG/webviewable/475277.pdf
That's big, but not unthinkable. There are plenty of "large hotels"
and 300-bed hospitals located near U.S. highways, with large power supplies.
- Jed
