The average Walmart has about 180,000 square feet of flat rooftop space — about the size of three football fields — that could hold enough solar panels to power nearly 200 hundred homes for a year, according to a new report from the environmental advocacy organization PennEnvironment.

“The opportunity that we uncovered through our research is astounding,” said Rachel Vresilovic with PennEnvironment, during a Zoom press conference last week. “The rooftops of America’s big-box stores and shopping centers have the potential to generate nearly 85 terawatt-hours of solar electricity each year. That’s the equivalent of the amount of electricity that would power 8 million homes, or 30,000 typical Walmart stores.”

There are more than 100,000 superstores in the U.S. with about 7.2 billion square feet of rooftop space — the size of El Paso, Texas.

“Our report also shows that Pennsylvania ranks ninth in the country for potential annual solar generation from big-box store rooftops. That means potentially generating enough energy annually to power 297,000 homes,” said Vresilovic.

“The data in our report estimates that Pennsylvania could reduce the state’s global warming pollution by nearly 2 million metric tons of CO2, which is the equivalent of taking 400,000 cars off the road.”

Rooftop solar at a Walmart in Puerto Rico. Photo courtesy of PennEnvironment.

Chester County Commissioner Marian Moskowitz also spoke in favor of the concept.

“We know that solar energy is not only a good way to reduce fossil fuel consumption, it’s a smart business decision,” said Moskowitz. “It gives our businesses the ability to lower their energy bills and hedge against unpredictable rising energy prices. Big-box stores use massive amounts of electricity, accounting for 5 percent of the U.S. total. These chains could reduce the overall demand for electricity in the country if they generated their own power.”

This isn’t a new idea. According to the Solar Energy Industries Association, the four companies with the most solar panels installed as of 2019 — Apple, Amazon, Walmart and Target — had solar installations totaling almost 1.4 gigawatts of capacity in that year.

“Right now, thousands of big-box stores and parking lots have no solar panels installed,” noted Vresilovic. “We’re missing out on a great opportunity to produce clean renewable energy right here in Pennsylvania, and that needs to change now.”