U.S. Superstores Have Huge Solar Potential, Says Report

The rooftops of the U.S.’ so-called “big box” retail stores and shopping centers could host 62.3 GW of solar photovoltaic capacity, equivalent to the amount of electricity used by more than 7 million average U.S. homes and more than triple the solar PV capacity that has been installed in the country to date, according to a report released by Environment America and co-authored by Frontier Group.

The report notes that the 10 big box companies with the largest amount of retail space in the U.S., alone, have enough rooftop space to host approximately 17 GW of solar capacity on their retail stores. Those companies include Walmart, Target, Home Depot, Lowe’s, Sears Holdings (including Sears and KMart), Macy’s, J.C. Penney, Kohl’s, Costco, and TJX (including Marshall’s and TJMaxx).

Environment America says the roofs of large stores are perfect locations for solar panels, as they are largely flat and vacant and almost always fully exposed to the sun. According to the report, the U.S. has more than 102,000 big box retail stores, supercenters, large grocery stores and malls with more than 4.5 billion cumulative square feet of available rooftop space on which solar panels could be installed.

According to the latest data available summarized in the report, titled “Solar on Superstores,” Walmart leads the pack in total solar panels already installed (with at least 142 MW of on-site solar), followed by Costco, Kohl’s and IKEA. In addition, the report says the top 25 companies have installed a total of 1,462 solar energy systems at business locations across the U.S.

Rooftop solar is also good for business, the report continues. Electricity produced by rooftop panels on all the big box stores and shopping centers analyzed in the report could offset the annual electricity use of these buildings by 42%, saving these businesses $8.2 billion annually on their electricity bills.

For example, the report says Costco reported savings of $300 per day on average over three months after installing solar panels on two of its California stores.

The report adds producing electricity on rooftops, close to where the electricity will be used, also reduces losses that happen during electricity transmission – losses which totaled 5% of electricity sales in 2012.

Shouting from the rooftops
Environment America releases its report as the advocacy group calls on Minneapolis-based Target to go big on solar. The group says Target has pledged to put solar panels on a quarter of its stores, but the company could cut pollution dramatically and even save its customers money by putting panels on all of its nearly 2,000 rooftops in North America. According to Environment America, Target’s solar potential is second only behind competitor Walmart.

“Target has made progress on solar,” comments Bret Fanshaw, solar program coordinator with Environment America. “But, just like the ads say, we ‘expect more,’ especially when the company has so much potential to cut pollution, reduce energy waste and save money.”

In addition to calling directly on Target and other major retailers to install solar panels on all of their roofs, Environment America has urged government policies to help facilitate rooftop solar, such as net metering and third-party financing.

“Rather than waste energy through transmission or fire up expensive, polluting peaking power plants to meet temporary demand, we should do all we can to encourage the production of solar energy on our rooftops, close to where we live, work and shop.” Concludes Environment America’s Fanshaw.

The full report is available here.

Photo courtesy of Freedom Solar Power and SMA America: A solar installation atop a Whole Foods store.


  1. If solar panels were put onto 5,000 square miles of desert in the US they would produce enough electricity to power all 100 million homes in the US. Utah alone is 85,000 square miles, about half is desert. Then there are all the deserts in Arizona, New Mexico, California, Texas etc. If solar farms were spread right across America from the East Coast to Hawaii they would produce electricity for around 16 or 17 hours a day. Mostly during the time we use the most electricity, during our waking and working hours.
    Just saying.

  2. There would also be savings in air conditioning costs as the PV systems would shield a large portion of the roof top from direct solar radiation


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