In a message dated 02/10/2009 18:41:31 GMT Standard Time, bruninga@usna.edu writes:

Again, there is a BIG difference between solar design for stand-alone battery systems (must point south, optimum angle, etc) and grid-tie systems that can be anything from SE to SW and even FLAT and still be only a few percent off peak!.

Sorry Bob, But a few percent is certainly not correct for the installation I'm responsible for. I have a set of panels pointing at the horizon at my local school and they are about 40% down at midday. The efficiency is directly related to the amount of sun falling on the panel....well some relationship to the tan of the angle in radians....or whatever it was I calculated and then measured. Actually the angle to the sun is critical for max efficiency. (Obviously missed completely by the %7'!** who approved this installation.)

_http://www.sunnyportal.com/Templates/PublicPageOverview.aspx?plant=7350f0ac -1a01-4248-89cc-90607f32caaf&splang=en-GB_ (http://www.sunnyportal.com/Templates/PublicPageOverview.aspx?plant=7350f0ac-... ng=en-GB)

If you want to check out the efficiency of an installation near you, just have a quick search of the "publicly available plants" at _www.sunnyportal.com_ (http://www.sunnyportal.com)

David G0MRF