There’s Vast Untapped Potential for Solar Rooftops in the US, Says Google
When Google first launched a website two years ago that collects data on solar rooftops, called Project Sunroof, it only covered a few cities. But this week, the search engine giant announced the solar site is now crunching data for every single U.S. state, including 60 million rooftops across the country.
The expansion means that Google’s Project Sunroof is starting to get a much clearer picture of how much rooftop solar capacity there actually is in the U.S. Project Sunroof uses data from Google Maps and Google Earth, combined with 3-D modeling and machine learning to determine the solar electricity potential of individual roofs.
Potential solar customers — or just the solar-curious — can enter their addresses into the site and get information about how much a solar system on their roof might cost and how much money they might save over time by going solar.
Google’s product manager Joel Conkling told GTM the goal of Project Sunroof is “to get data into the hands of people thinking about solar, and who are making decisions about solar.” He added that “the hope is [to] help people make more quantitative decisions about solar.”
The large amount of data being collected by Google also means that the internet company’s project could be a helpful tool not only for consumers interested in solar, but also for solar companies looking to bring in new customers, as well as academic researchers and even utilities.
Now that Project Sunroof’s availability is countrywide, Google’s amassed data has started to reveal some interesting trends and information. For one thing, Google says that 79 percent of the rooftops it’s analyzed are viable for solar, which is good news for rooftop solar providers.
That doesn’t mean that 79 percent of rooftops should or will adopt solar, though. Rather, it means that 79 percent technically get enough sun to be able to accommodate solar panels.
That finding is likely a generous interpretation of the data. For comparison (though it’s not apples-to-apples), a National Renewable Energy Laboratory analysis from January 2016 — arguably the best technical analysis to date — found that the rooftop space on all buildings in the U.S. could generate about 39 percent of total national electricity sales. The NREL report, which uses data from lidar and software modeling, also found that a sunny state like California could generate 74 percent of the electricity sold by utilities in the state.
Solar industry watchers know that sun potential is only a part of the equation for when a customer decides to go solar. Other major factors include state renewable energy targets, net metering rates, tax credits and available financing.
While keeping that in mind, Project Sunroof still plays a role in exploring the upper end of what’s possible. Google’s Conkling says Project Sunroof is specifically meant to report on the technical potential of solar. Google does include economic data in its solar price quote for users based on address and ZIP code. But Project Sunroof does not offer a comprehensive view of the rooftop solar market.