The Washington PostDemocracy Dies in Darkness

Now Google can tell you whether it’s a good idea to put solar panels on your roof

FILE: Solar panels in Rockville, Md. (Photo by J. Lawler Duggan/For The Washington Post)

Despite its benefits, switching to solar power can be a daunting prospect for the average homeowner. From the cost of purchasing or leasing your own solar panel system to uncertainties about how much power it’ll actually generate, taking the leap can seem like a risk.

A new Google project is seeking to allay some of these concerns with a tool that estimates the amount of energy and savings solar power could generate for any given home. Project Sunroof, which just launched in pilot form on Monday, allows users to search their address and find out the number of square feet available on their roof for solar panels, the number of hours of usable sunlight that could be generated, and the amount of money it could save. It’s currently available for residents of the San Francisco Bay Area, Fresno and Boston.

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The tool uses the same aerial imagery data used for Google Earth to evaluate a rooftop’s solar potential, taking into account factors such as shade from nearby trees or buildings. The tool also factors in local annual weather patterns to make a more informed evaluation about how much sun will be hitting the roof. Once they receive their results, users can input data on their typical energy bills to get better estimates on the amount of money they could save each year by installing solar panels. It also links users to solar providers in their area.

Considering that cost is likely to be a major question for many people considering the switch, the tool includes detailed information on the price of installation. It draws on information from banks and other financial institutions to provide estimates on how much it will run a resident to lease, buy or even take out a loan for the panels, according to Barry Fischer, a global communications and public affairs officer at Google. Annual and long-term savings are likely to differ depending on which route a homeowner decides to take.

The project is led by Google engineer Carl Elkin, who started work on the tool through Google’s “20 percent time” program, a policy which, in the past, has allowed employees to spend a fifth of their time working on their own projects and ideas. While it’s still just a test for now, it may expand to other parts of the country in the coming months.

It’s also one of a string of renewable energy-oriented projects Google has been involved with in recent years. In 2013, the company announced its investment in Africa’s largest solar energy plant, the Jasper Power Project in South Africa. And its Mountain View campus is also home to one of the country’s largest corporate solar panel installations.

Whether Project Sunroof makes a difference in the number of people switching to solar energy is another question. But the solar providers Google is partnering with seem optimistic that it will help people make better-informed decisions. “For the first time, residential solar systems are able to give people a real choice when it comes to where they get their electricity. …  And it’s saving them a lot of money,” said Greg Butterfield, CEO of Vivint Solar, in a statement. “Google is helping us provide an amazing service to even more people.”

And in a blog post about the tool, Elkin wrote, “…as a volunteer with the Boston-based solar program Solarize Massachusetts and a solar homeowner myself, I’ve always been surprised at how many people I encounter who think that ‘my roof isn’t sunny enough for solar,’ or ‘solar is just too expensive.’ Certainly many of them are missing out on a chance to save money and be green.”