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See How Renewable Energy Works in Your Backyard

December 19, 2008

Photo of a large two story home with the roof exposed to the sun. On the right of the home is a windmill.

NREL's online tools help consumers determine how economically wind and PV systems will operate in their locations. The IMBY tool can help this homeowner decide if a modern wind turbine or solar panels would make sense.

Suppose you live in an 100-year-old mansion and want to reduce your utility bill – and your carbon footprint – by integrating it with 21st century renewable energy technology.

Are there sufficient solar and wind resources at your location to generate electricity? How much electricity? And how long would it take to recover the cost of your new system?

NREL's new online analytical tool, In My Backyard, helps to answer those fundamental questions. And it is not limited to mansions. Homeowners, businesses, and researchers use IMBY to develop quick estimates of renewable energy production at locations throughout the continental United States, Hawaii, and northern Mexico.

New and Improved Version

IMBY was introduced last May. Since its release, NREL Geographic Information System scientist Christopher Helm has been refining the online tool. The upgraded version generates performance and cost information that is even more specific to locations and renewable energy systems that consumers want to explore. He has made IMBY's online interface easier to use, too.

"We want to make this tool sensible and meaningful to the everyday household," Helm said. "We don't want people to have to be completely literate in photovoltaics to use this successfully."

To get started, visit the IMBY Web site and follow the onscreen links.

What pops up should look familiar. IMBY uses a Google Maps interface to allow users to choose with pinpoint accuracy where consumers might want to install a renewable energy system.

Go the box on the upper-right hand side of the screen and type in the property's street address, such as "400 East 8th Avenue, Denver, CO."

This happens to be the Governor of Colorado's residence at Boettcher Mansion, built in 1908.

(Colorado Gov. Bill Ritter already has added a 9.8 kilowatt solar system to the official residence that produces 11,200 kilowatt-hours per year. The average Colorado home consumes 7,200 kWh each year.)

Zooming In

IMBY virtually whisks you to the address and offers a bird's eye view of the property using a satellite image. It is highlighted by an icon of a giant green push-pin to mark the spot.

Next, select solar or wind. The online tool estimates solar photovoltaic (PV) array and wind turbine electricity production for the location based on your specifications of system size, location, and other variables. Then it generates information for that location from one of NREL's renewable resource databases to estimate your total potential renewable electricity production.

Based on the typical cost of electricity for a residential customer in that location, IMBY estimates the annual electrical bill for the address with the new system in place – including whether the system has the potential to deliver an electricity surplus back to the utility.

Then, it takes the cost of an installed system – say, $30,000 for a 4 kilowatt PV array – and factors the variety of ways a customer can reduce the system's cost. These include using up-to-date incentive and rebate information.

Generating Savings

Finally, IMBY estimates how many years it will take for the property owner to recover the system's cost. This is calculated through a determination of the total system cost and the amount of electricity the system will generate on an annual basis.

And throughout the exercise, the online user can see a variety of charts illustrating the system's potential performance and estimated cost savings by year and month.

"Now IMBY emphasizes the economics of renewable energy and net-metering," Helm said.

Next summer, Helm plans to introduce IMBY 2.0. He wants to add features that PV installers and property developers would like to see, such as the ability to run multiple PV configurations on a location for comparison and deeper analysis.

While IMBY can estimate the production you can expect from a PV array or wind turbine, it cannot determine if such a system is right for your property or pocketbook. To learn more about these systems, see Learning About Renewable Energy.

Image of a computer screen with an aerial photo of a parking lot on the left, several roofs and a park. To the right of that image is text in the In My Backyard software tool.

NREL's In My Backyard online tool allows users to view a satellite image of a property. Shown is the Colorado Governor's mansion in Denver.

— Joseph B. Verrengia

Photo courtesy of John Masson