## "save energy by using the power company's spikes"? is this fact or fiction?

Started by AdironDoc, May 06, 2011, 06:35:55 AM

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I keep getting ads for a device that will reduce my electric bill by "up to thousands" and was told by someone I should use it for any new cabin project. Well, being off grid it's a no starter, but it did stir my curiosity. If something like this were the real deal, why isn't it universally used? So I ask those with more experience in electrical engineering for a critique on this. Essentially their premise is that the utility sends out inefficient power containing dips and spikes in voltage. Further, that the spikes are wasted, that these spikes can somehow be stored a bank of capacitors, and lastly, that what is stored in the capacitors can be harvested to offset the power consumed in the household.

As my electric bill is measured not by incoming voltage, but by flow, even if there were to be spikes in voltage, why would that effect my meter reading? If there were spikes in current, then I'd be paying for them anyway as they pass my meter. Sounds fishy to me. Anyway, I'll stay open minded and hear any thoughts to the contrary.

Doc

#### JRR

#1
I'll take a wild guess about what they are offering: Power Factor Correction.  The power company delivers electrical energy in approximate sine waves ... a sine wave of voltage ... a sine wave of current.  If the load is purely resistive in nature (such as incandescent lamps or heating strips) the current sine wave is in sync with the voltage wave  ... and the transfer efficiency is as good as it gets ...  the transfer factor is "1".  However, as we start adding motor loads ... heat pumps instead of heat strips ... washing machines, refrigerators, etc, etc ... the load becomes more "inductive" in nature and the voltage wave shifts away from the current wave, ... this is not as efficient, and the transfer factor lessens getting as low as .85 sometimes.  The wasted energy appears everywhere in the system ... at the generators ... along the power distributrion lines ... in your home.  You are charged as though the current wave is in sync with the voltage wave ... even though it isn't.

What can be done about this out-of-sync condition?  One simple correction is to add capacitors near the inductive loads.  If the capacitors are large enough, the transfer factor can be fully corrected ... all the way back to "1".  But capacitors of any significant size are very expensive to manufacture ... so there quickly becomes a point where it is cost prohibitive.  Large power customers have other options ... things that look like motors but are "synchronous reactors" ... these act as capacitors on a sine wave.

I suspect the device offered similates one of these gadgets.