Big bang ahead for big-box store solar panels?

Ikea leads the way, with environmentalists urging others to follow.

(A native of England, Matthew Diebel is a veteran journalist who has worked at NBC News, Time, USA Today and News Corp., among other organizations. Having spent his childhood next to one of the world's fastest bodies of water, he is particularly interested in tidal energy.)

Real estate, real estate, real estate. That’s what big-box stores such as Walmart (WMT), Target (TGT), Home Depot (HD) and Costco (COST) have in abundance, with the average Walmart store, for example, having about 180,000 square feet of roof space, according to a report by nonprofit Environment America.

And then there are the parking lots.

And what’s above these giant spaces? For part of the day, at least, the sun — which means they could be prime places for solar panels.

“Every rooftop in America that isn't producing solar energy is a rooftop wasted as we work to break our dependence on fossil fuels and the geopolitical conflicts that come with them,” Johanna Neumann, senior director for Environment America's campaign for 100% Renewable, told CNN. “Now is the time to lean into local renewable energy production, and there’s no better place than the roofs of America’s big-box superstores.”

Some companies, though, have already embraced the sun. Swedish furniture phenom Ikea, for example, now has solar arrays installed on the roofs of 90% of its U.S. locations. And last year the chain announced that it had installed shady car canopies in the parking lot of its Baltimore, Md., store that have solar panels on top and cool autos underneath. “With each installation, IKEA moves closer to its ambitious sustainability goals and we’re glad to be a part of that mission,’’ said Erik Schiemann, CEO of Schenectady, N.Y.,-based Distributed Solar Development, which partnered with the home goods giant in its solar strategy, which also includes parking lot power at other locations in Maryland and in California.

Together, the Baltimore roof and parking lot panels have cut the amount of energy Ikea needed to buy by 84%, the company reported.

Time for others to play catch-up? Leveraging the full rooftop solar potential of superstores would generate enough electricity to power nearly 8 million average homes, Environment America’s report found, and would cut the amount of planet-warming emissions equivalent to 11.3 million gas-powered cars.

Attention, shoppers, this could be coming to a store near you.