Feb 24, 2008 06:45 am
Re: Minimum watts to grid tie?
Assuming that you have allready reached an apogee where the energy efficiency of your home is concerned, think in terms of, offsetting the electric needs of a particular appliance or the perhaps the gas or oil needs for heating, which ever may apply.
If electric energy, take for example the refrigerator. Lets say it consumes on average over a year, 150 watts in 24 hours. In your region you have an average over a year of, 3 hours of full rated power from PV in 24 hours. That would be, at minimum, a 50 watt PV array.
Remember these figures are an average and they are only an example to demonstrate the math.
Typically, small systems as in the example I gave do not exist anymore. At one time a company called Solarex made PV modules with a built "microinverters" and some folks might just plug it right into a wall receptacles. Not Code legal (National Electrical Code) but it happened.
Oh, by the way, Solarex which was a subsidiary of the American Oil Company (Amoco) sold out along with Amoco to the British Petroleum company (BP) who also produce PV modules. Next thing you know Shell Oil, General Electric, almost everybody is making PV modules. Then they proclaim that there is a shortage of raw materials for making PV cells and the price of PV goes through the roof. Smells fishy to me.
Sorry 'bout that. I got off the subject. I guess you can tell, I am not happy with the PV industry right now. Back to the subject...
You know, the widespread utilization of electric energy by human beings on the planet Earth is only about 100 years old. Beginning with the likes of Thomas Edison, Nikola Tesla, and George Westinghouse. In retrospect, human beings have lived on the planet Earth for more than 7,000 years. No matter what your religion teaches, you cannot disagree with these facts. This means that for over 6,900 years, human beings did more than just survive on the planet Earth, the flourished, without the utilization of electric energy.
Now look at us today only after 100 years with it.
Oops, there I go again.
I am going to sign off now. Best of luck to you Paul. If you truly want minimum watts, then just turn it off!