reply to post by Eurisko2012
Isn't the local power company obligated to pay the farmer for all
power generated by the windmill?
Let me shine a little light on this...
Yes, if you produce more electricity than you use, and that electricity causes your meter to 'run backward', it is now a law in the USA that the
local electric supplier must pay you for that power. But it's a little more complicated in practice.
Electrical energy at the wholesale level (which is what you are paid for your excess), is charged at a varying rate depending on what the electricity
is worth at that time
. During high peak demands, the wholesale price of electricity rises; during low-demand times it falls. Unless you can
prove, with 'approved' instrumentation, when your power was generated, you will receive the lowest price your power distribution company paid for
electrical energy at the wholesale level in that month
Of course, such information can only be gleaned from expensive monitoring equipment, which large producers have.
There are also some other 'tricks' being employed. The frequency is the tightly controlled parameter on electrical power; not the voltage. That is
why you will typically see such power requirements listed as '125VAC', '117VAC', '120VAC', etc. The RMS voltage can easily vary from 100 to 140
volts on a typical power line. This variance is of little consequence in older technology (such as light bulbs or heating appliances), but can be a
problem with computers, televisions, etc. So, they make voltage regulator chips to throttle any over-voltage back to a safe level. Every modern gadget
has such regulators built into the circuit.
Now, in order for power to flow back into the grid from your production, the RMS voltage on the grid has to be lower than the RMS voltage on your
system. That means that you will typically only supply power back during high-demand, low-voltage times. And yet, you get paid for low-demand
Also, if there is a phase difference between your AC and the AC of the grid, the power will flow into your meter during one part of the cycle and out
during the other. The result evens out; as much power flows in as flows out. Since your meter registers the resulting effect, this inefficiency evens
out as well. But since your small generator is 'bucking' the larger grid, you will use more energy to produce the same amount of power for
This applies to any phase shift, even small ones. Large phase shifts tied into the grid will produce the equivalent of a 'short circuit',
overloading your generator while spinning your meter at an alarming rate (or popping breakers if you're lucky).
I suggest anyone who wants to produce their own power not try to tie into the grid. You receive a small portion of what your production is worth, you
typically overburden your generator unless you spent the $$$ to precisely align the phases, and should the grid go down, your production will be
drained by everyone else. I would rather suggest a self-contained system with an emergency relay to connect back to the grid automatically in case of