http://www.technologyreview.com/view/521...
One issue is that the voltage falls as the charge is depleted. This implies higher voltages are necessary. Yes some sort of electronic inverter can help, but stepping the voltage up has diminishing returns, considering half the voltage is twice the current for the same power. The voltage will fall very quickly once the capacitor is below the voltage of the load. The result is a capacitor would discharge up to some point then more and more quickly. I mean that the energy stored in a capacitor cannot be fully utilized for running a load. Maybe it will work better by just doubling the storage size and having two or 3 times the voltage required.
The energy for your house example is 15kWh per day, so in joules, 54MJ. If stored at 1000V then 200F stores 100MJ. When voltage is down to 350V it still stores 12.25 megajoules, so 87 useful MJ (24.4kWh). Maybe something like that works. There is no equipment available that does this that I know of, though it might be do-able, after a few more years. I would be a bit wary of this 'bomb in the basement'. Maybe as time goes on we will find that it all works fine and is safe. This is roughly the equivalent of a 650V battery with a 40Ah capacity, which is well proven and has a slower release (though still spectacular enough). Presumably the super-capacitor can discharge very quickly, and the peak power is a function of J/s. If 100MJ goes in 1s the average power level during that second is 100MW. The energy is the equivalent of 21kg of TNT.
Here is someone who was speculating about just the same thing: http://peakoil.com/forums/post135964.htm...
But there are differences between batteries and capacitors in power density, energy density, expected life, charge times, and the nature of the way the charge is held in the device: http://www.ultracapacitors.org/index.php...
Powering a home with ultra caps involves trying to put energy density in a devices known for its power density this kind of joining is exactly where the research is going: http://www.technologyreview.com/news/417... Given enough time, money, and space all things are possible. We used to have computers that could fill a building and now the same capacity will fit into a phone or a watch.
Anything over 1F and you may as well call it a battery IMHO. In fact systems for houses or electric cars that want to store electrical energy tend to charge up huge banks of 12V car batteries, which rather suggests that super capacitors are too expensive.
If money and space are not a problem, then this can be achieved.
However, this is not practical for the simple reason that batteries are much more cheaper.
I saw a few youtube videos of people powering drills and lightbulbs, and exploding watermelons with capacitor banks. One guy had a 10,000 farad Supercap. Bank.
According to my math, it'd take about 600 of his supercapacitor banks to power an average 15,000kwh home for 24 hours.
Upon looking up how much this would cost, it made a little more sense why my question has no answer still.
Has anyone ever tried to store a house's power in capacitors? Like a solar/wind powered home that's off the grid. Would it be practical if money and space requirements weren't a problem?
