AI Case Study

"Stanford University engineers have developed a way to find every solar panel in the contiguous United States.

Solar installations are difficult to track and even more difficult to manage. Some solar installations are privately owned, on the rooftops of family homes. Others are industrial-size and owned by utilities, spanning acres of land. Those solar panels are all pumping out various amounts of energy depending on their size, cloud cover and location.

Without thorough data, utility companies can’t plan their energy needs, solar installers don’t know the ideal areas for more panels and lawmakers can’t incentivize adoption of renewables.

That’s where the Stanford research team comes in. A new paper published Wednesday in Joule presents how to spot solar panels buried in an enormous database of satellite images using a deep learning computer model. Utility managers, researchers, policy makers, developers and curious onlookers can check out an open-access and aggregated version of this data online.

“This is really cool work,” said Budhendra Bhaduri, a scientist at the Oak Ridge National Laboratory in Tennessee who was not involved in this paper. Publicly available information on this scale, he said, could help revolutionize the future of energy.

Once DeepSolar had identified a pixel that it recognized as a solar panel, the network could use that information in concert with the pixels located nearby to calculate the size of solar installations across the country. The result is a database of the location and size of every recognizable solar panel across the lower 48.

DeepSolar found sunnier areas had greater solar adoption than places with less average sunlight, as you might expect. But the model could put an exact figure on the sunshine cutoff point, where residents were unlikely to adopt solar. Places below 4.5–5 kilowatt hours of solar radiation per square meter per day — for example, decently sunny cities like Norfolk, Virginia or Bend, Oregon — had essentially no rooftop solar panels.

Another surprising result, Rajagopal said, was that solar panel adoption was higher in areas of increasing average household income, until the average reached about $150,000 per year. At that point the rate of solar panel installation leveled off. “That was quite striking,” Rajagopal said, because there’s no clear explanation yet for why wealthy people would adopt solar at a slower rate than middle-income households.

Policymakers who want to incentivize solar adoption, for example, would know where to apply tax breaks for maximum impact.

Utility managers could use the information to plan for their own power production in the short term (less on sunny days, more when heavy clouds block the sky). In Germany, energy overloads due to the rapid adoption of renewables have spawned power surges and occasional increases in carbon emissions from fossil-fuel plants. Utilities can also use DeepSolar to determine whether new and expensive power plants might become obsolete before they’re built.

Entrepreneurs will know where to set up smaller, decentralized power grids thanks to DeepSolar.

“It adds a lot of resiliency in case of hazards and disasters when you are the generator of your own electricity,” Bhaduri said. “I always think about the upcoming disruptors. What is the Uber or Airbnb for energy? Who will create micro-energy economies where people are sharing energy with each other?”"