For the last week or so my Facebook and other sites have been inundated with ads for Elon Musk’s Pro Power Saver. When I looked around I found that there are all kinds of brands of these devices. you plug them into a vacant outlet and they start to save electricity by “cleaning up” Dirty current”. This sounds like one of those things that wise people say “If it sounds too good to be true. . .” So is it too good to be true? How do they work in laymans’ language if indeed they do work?
Some of these can be had for $10.00 or so. Do they work? And do they do anything to improve the use of solar power?

 

"Power companies hate it when you do this one thing..."

Scam on two fronts.
Elon Musk nor Telsa make or endorse any kind of device like this. Snopes

Also, these devices simply don't work. They are based on something called power factor correction, which is something that can save large industrial/commercial plants money in electricity usage. But they have different electrical services and equipment than a residence - and their power factor correction equipment is a LOT bigger than a little box that plugs in.

So, definitely not worth the $10. Not even worth the $0.50 that it probably cost to manufacture the device.

 

“If it sounds too good to be true. . .” So is it too good to be true?
Yes

"How do they work..."
They don't, at least for saving electricity. They consume power so they do the opposite of saving.

"...do they do anything to improve the use of solar power?"
No, solar is DC. Those so called "power savers" are AC devices. Apples and oranges. Any solar system will use an inverter to convert DC to AC. It won't convert a the modified sine wave from a cheap inverter into a nice, pure wave form.

 

The "better" models have a larger capacitor in them for the ultimate smoothing experience.
Those power savers come and go in cycles.
They don't save any energy.

 

What is power factor?
Explanation that gives you an idea of what power factor is but is not rigorously correct.
Imagine your child is on a swing set and you stand back behind him and help him out with a push every time he comes back at you. Now imagine that you push him at not quite the correct time each time. It takes you more effort to get him to a given swing height compared with pushing him at the right time. Correcting the power factor means adjusting your pushes to be at the correct time.

When you correct the power factor in the home (after the meter) your electric bill will go down. But the error in a home setting (a residential neighborhood) is small so correcting it will save a very small amount of money, perhaps just one percent.

(Correcting power factor is done to aim at a standard, unlike the best time to push your child versus the best time another parent uses to push his child.)

What is dirty power?
The AC voltage waveform is not a pure sine wave. When you have dirty power with a repeating waveform (as opposed to random spikes) , that (60 Hz) current is a mixture of 60 Hz and multiples (120 Hz, 180 Hz, 240 Hz, etc.) It so happens that a capacitor connected so as to "short circuit" the line will short out the highest frequencies to a greater extent and the capacitor is chosen to not lose too much of the 60 Hz. This brings the waveform closer to a pure sine wave. Some electronic equipment behaves unfavorably when fed dirty power thus cleaning up the power with the capacitor helps. Note that the electrical energy representing the higher frequency content (the harmonics) is billable or is included in your generator's maximum output and cleaning that up with simple means is waste you pay for.

(A single capacitor or certain other simple circuits to clean up dirty power might change the power factor in an unfavorable way and also will leave behind much of the nearest (120 Hz, 180 Hz) harmonics). So really good devices to clean up dirty power are more complicated and more expensive.)