Can we power our houses for free using capacitors?

Question

Since the power authority only charges for Watts, not VARs, can't we all just get a big bank of capacitors (I know it may be expensive), and run our electrical appliances with that? (Can I assume that there are capacitors capable of charging faster than they discharge?) The grid would only see those VARs and I guess I'm also asking if those capacitors would decouple our appliances from the grid? Let me know your thoughts....thanks

Here's the scenario I'm presenting: connect the grid power to a capacitor bank, which means you're only using VARs, then from that bank power is sent to appliances which would use mainly watts, but maybe also some VARs. I am an EE student and I took a class in Power Systems and we learned the power company only charges for Watt usage, not VAR usage -- as if you charged up capacitors (or inductors for that matter). I would think this could be illegal, but it would have to possible first right?

Answer 1

No the power meter on your house is actually a current meter. Granted it assumes a power factor of 1, however your still takeing in current. At most you might be able to lower your bill a tiny bit.

As far as powering appliances no...because your appliances require AC power...what your thinking about is powereing a DC device to do so you'd have to convert the AC to DC just to charge the cap. and there is always losses so in the end it would come out less efficient.

Answer 2

No

You may be able to reduce you VAR by getting your power factor closer to one with capacitors. Though if you put to many in place you will actually raise your VAR. While they say the charge you for watts they assume a 1 power factor on your meter so they really charge you for VA not for watts. So by reducing your VAR you can reduce your VA and slightly change your bill.

If you put in the right amount of capacitors to cancel out the inductance of the loads in your house essentially making it a purely resistive load and minimizing the current you need to get your needed power.

The capacitors would probably cost more then you will save on your power bill though.

The average power factor for a house is between .9 and 1 so taking it to 1 you would save at most 10% on your power bill.

If you are not an electrical engineer or at least a technician I would not try this. Clearly from you lack of understanding you are not one, or you are a very bad one.
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Ok i read your update you are trying to charge them then discharge them into your house. to charge them you would need a rectifier which would have losses also you would make them into a real load and not a reactive load. Then you would have more losses turning it back into AC to run you devices.

The only way you get them to be a VAR load is if they are in a constantly AC circuit just like inductors. If you charge them from the grid then discharge them into your house the grid will get a real power loss from this not just reactive. Your system would actuly cause you to use more power.

It comes down to the basic the amount of matter/energy in the universe is constant. You can't get power from no place that would be magic.

You remind me of a guy I knew back when i was in navy nuke school back when i was in the navy. He was always coming up with ideas that made no sense because he only half understood a lot of the stuff we where learning. His doughnut motor idea was great. I forget what it was now but it was crazy.

Answer 3

The power company charges us for energy ( watt hours) and not power (watts). Capacitors store energy and the energy is
E= (1/2) x C x V^2... where C is the capacitance and V is the voltage. When you charge a cap you are charging it with energy so you would get charged for it. AND caps cannot store a,c, currents sou would have to turn the a.c. to d.c. to store it and then back again when you use it. The conversion is not 100% efficient so it costs you energy and in the long run it would cost you more.

Answer 4

there is still the law of conservation of energy. the power used to charge the capacitors will still be used by the load- and capacitors are designed to give higher volts over a short period- slowly draining a capacitor reduces their ability to hold a charge.
A good way to see this in practical application is to take contstant amp readings of a capacitor assisted motor during startup- and then take another motor that uses the capacitor during run-time and measure the amps, and then take the capacitor off and monitor the motor run amps without the capacitor.
Finally the US Patent office quit issuing perpetual motion patents a long time ago because of the first thing I mentioned.

Answer 5

Something would have to power the capacitors. You don't get energy for free at least not in physics. I believe the capacitors would need a flow of electricity to charge them.

Answer 6

Sure, you can get energy from nothing. It happens all the time in Nowhere Land.

Answer 7

Yes but it is against the law.

Answer 8

tisk, tisk