# Solar Power

(Notice to reader:  Please note that there are Microsoft Excel spreadsheets embedded in this web page so the reader can try different scenarios.  If you have Excel loaded on your local computer the page will come up very quickly. If you do not have Excel it will still load and be usable but it may take 15-30 seconds.  I am working on alternative software for the page.)

Solar power is by far the most readily available source of power we have.  Let’s run some simple numbers to confirm this:

Let’s do a simple comparison between a 6ft in diameter wind turbine located in Maine and a 235W Sharp solar panel.

First we will look up the average wind speed for our location from the National Renewable Energy Lab’s website (link to map).  For our example let’s use 4 meters per second or 8.9 miles per hour as the average wind speed.  Typing that value in the interactive spreadsheet below we can see that output from a good turbine will be:

267.4 kWhrs per year.  OK..That’s not tiny but my farm house with an electric stove, dryer, in law apartment, and hot water heater uses 1200 kWhr’s per MONTH.  That six foot windmill isn’t going to get me off grid any day soon.

If you play with the calculator the numbers say I need a windmill 45 FEET in diameter to be off grid with wind alone.  There are obviously other issues such as when the wind doesn’t blow but those can be saved for the wind page.

Now let’s do the same thing for the solar panel.  We will look up the incoming solar power from the National Renewable Energy Lab ( here ).  Reading from the map the local solar intensity is about 4kWhr/(m^2day).  So crunching the numbers:

So a single solar panel can make much more power than a 6ft in diameter wind mill.