[amsat-bb] Re: Satellite Solar Power (indoors) and out

Bob Bruninga bruninga at usna.edu
Wed May 16 20:48:27 PDT 2012

> What's funnier is the 35 million spent on solar panels...
> to save $475k a year...[and] take 70 years to break even.

Its a lot more than breaking even.  Don't forget about a few million tons of pollutants and burned fossil fuel byproducts, and destroyed land and habitat that now don't have to be sacrificed to produce all that energy we demand...

> ...I think that savings is probably based on every day
> being sunny. Indiana is not what I would call a great 
> place to operate solar panels. Many cloudy days and in 
> winter, it's possible for ice to cover objects for long 
> stretches of time.

ANyone can easily compare the real-10 year actual solar weather effects for anywhere in the country.  SImply google for "PVwatts" and pick the city and state.  It will compute the yearly power for any array and is based on the 10 year actual climate history for that site.

A quick check for Indianapolis shows a 10 kW array will generate 12,238 kWH per year worth $893 per year.  A quick check for Houston Texas produces the same KWH (12,198) but the value is worth $1183 per year.  So unless Houston has lousy weather too, both are comparable.  The only reason that Indiana's payback is less is because their electricity is cheaper at 7 cents compared to 9 cents for texas.

The neat thing about the PVWATTS web page is that the entire country uses the model for designing systems because it gives REAL numbers based on the 10 year climate model, not just wishful thinking.

AH, I just did  it for Phoenix arizona and the same array would produce 16,170 KWH per year worth $1374.  SO yes, Indiana is about 75% as productive as Phoenix, but I think you would like the weather in Indiana better than the 120 degree temperatures in Phoenix.

Bottom line, the effects of local weather are FULLY included in all solar estimates and anyone can do them in seconds on the PVWATTS web page.


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