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AUGUST 21, 2008   

Enough sun for ya?

Continuing on yesterday's sun-related theme, here's a great way to see if solar power might work for you. I read a small mention in today's Plain Dealer about the brand new RoofRay website, created by a couple of California computer entrepreneurs/engineers whose goal is:

to help consumers evaluate solar for their home or business and to create greater awareness for solar overall.

Sounded promising. Right after breakfast I tried RoofRay to see whether my house was a good candidate for a solar photovoltaic (PV ) installation, something I've thought about for several years now.

Satellite view of my house roof, with area for solar panels indicatedThe site is extremely easy to use. Start by typing the address of your house into the search box. You'll see a satellite view of your home based on Google Maps. Zoom in to get as close a view as possible

Next, with a few clicks outline your roof (choose the part that faces south or as close to south as possible). After finishing the outline, drag the red line to show the direction the roof slopes.

Now the magic happens: click the Performance tab to get a month-by-month chart of the expected performance of a solar array on your roof. This estimate is based on the size and orientation of your roof and includes factors like typical weather, cloud cover, etc.

Chart of potential solar output January-DecemberHere's the results for my house in frequently cold and cloudy Cleveland, Ohio. Looks pretty good.

The total estimated output for the year is about 11,000 kilowatt hours (kWh). My actual electric consumption for 2007 was about 5400 kWh. So the potential is there. Now, how about the cost of installation, projected payback time, etc.

I moved on to the Financial Analysis tab, pulled out a year's worth of utility bills, and filled in my month by month electricity costs for last year. The site promised me that this would give me a more accurate estimate than if I used an average monthly bill. I hit the Next button and...

...to my disappointment found that as of August 2008 the site is only programmed with a few California utility company rates. Nothing for Ohio, although hopefully that's coming soon.

Despite this rather glaring problem at present, this is a great site: easy to use, informative, thoughtful and thought-provoking (solar power can work even in Cleveland!). Try it and see.

An alternative

A quick Google search led me to the FindSolar estimator, a site with geographic/rate data for the entire U.S. that calculates what it would cost to build a system for your house and estimates utility cost savings, payback time, return on investment, etc. FindSolar's financial aspect is quite thorough, but unlike RoofRay there's no mechanism for using your roof size/orientation as part of the information used to calculate solar potential.

If your state's information is not yet part of the RoofRay calculator, the FindSolar site is an excellent alternative.

Bottom line

Solar PV panels to generate half my home's electrical needs would cost about $18,000 to install. With state and federal tax incentives this would come down to about $10,000. It would take about fifteen years to break even, although it doesn't appear that the FindSolar site factors in what we might gain from selling excess power to the utility in the summer, when our own usage is quite low.

At this point the numbers still seem a bit intimidating. I'm hoping that Ohio's governor and legislature come up with an energy plan that offers more in the line of incentives. If so, you'll see solar panels on my roof sooner rather than later.

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