Solar on Superstores
Big roofs, big potential for renewable energy

Executive Summary

Solar electricity generation capacity has increased about 40-fold between 2010 and 2021, making solar energy the fastest growing form of electricity generation in the U.S.1 That growth is due to solar energy’s low and rapidly dropping price, the immensity of America’s solar resources, and public policies that make solar power a viable and economically attractive option for individuals and businesses.2

America has only just begun to tap its solar resources. The United States has the technical potential to produce 78 times as much electricity as it used in 2020 just with solar photovoltaic (PV) energy.3 To accelerate the transition to a future of 100% clean and renewable energy, America must take advantage of untapped solar energy opportunities, including on the rooftops of “big box” superstores.

The flat, open, sunny roofs of giant grocery stores, retail stores and shopping malls are perfect locations for solar panels.4 The United States has more than 100,000 big box retail stores, supercenters, large grocery stores and malls, with almost 7.2 billion cumulative square feet of rooftop space.5

The rooftops of America’s big box stores and shopping centers have the potential to generate 84.4 terawatt-hours (TWh) of solar electricity each year, equivalent to the amount of electricity that would power almost 8 million average U.S. homes, or more than 30,400 typical Walmart stores. California, Florida, Texas, Ohio and Illinois have the largest big box store solar generation potential.

Putting solar panels on the nation’s superstores would be good for electricity customers, good for the grid and good for the environment.

  • Generating the full 84.4 TWh of clean solar power potential from America’s superstores would reduce global warming pollution by more than 52 million metric tons of CO2 annually – equivalent to taking over 11.3 million passenger vehicles off the road.6
  • Big box stores and shopping centers could replace half of their annual electricity use by fully building out their rooftop solar potential.
  • Producing electricity on rooftops, close to where the electricity will be used, reduces energy losses that happen during electricity transmission and distribution – losses that made up 6% of gross electricity generation in 2020.7 Solar power also makes the grid more resilient to outages and disruptions.

The map below shows the solar PV technical potential on big box stores in each state, as well as the reductions in global warming emissions each state would see by building out that technical potential. Hover over or click on a state to see its potential big box solar generation and greenhouse gas emissions reduction potential.

Many big box retail stores are already reaping the benefits of installing solar power on their rooftops.

  • According to the Solar Energy Industries Association, the four companies with the most solar installed as of 2019 – Apple, Amazon, Walmart and Target – had solar installations totaling almost 1.4 gigawatts of capacity in that year.8 That’s more than 11% of the total commercial solar capacity installed in the U.S. as of 2019.9
  • Walmart’s solar installations have already saved the company over $1 million, and the company’s installations in California were expected to provide between 20%-30% of each location’s electricity needs.10

To combat climate change, help their communities, increase resilience and reduce energy expenses, businesses should set ambitious goals to install solar generation capacity on their facilities and invest the time and resources needed to meet those goals. They should, additionally:

  • Investigate, catalog and report climate impact and energy use throughout their businesses;
  • Set strong, detailed and comprehensive environmental goals; and
  • Use their political influence to advocate for positive policy change.

Officials at all levels of government should implement solar-friendly policies that help to accelerate adoption of solar energy by America’s businesses. These include:

  • Extending and expanding the federal investment tax credit for solar power, as well as other tax incentives and credits;
  • Ensuring that businesses that generate solar electricity are adequately compensated for the benefits they deliver to the environment, public health and consumers through programs like net metering, feed-in tariffs and value-of-solar payments;
  • Enabling and enacting financing tools like third-party and Commercial Property Assessed Clean Energy (C-PACE) financing of solar installations to help remove financial barriers to solar adoption;
  • Supporting community solar power programs to allow businesses to go solar in partnership with their communities; and
  • Streamlining solar permitting and interconnection processes to make going solar easier and faster.

Cover photo: Solar panels on the roof of the Baltimore, MD, IKEA. Photo credit: IKEA



  1. U.S. Department of Energy, ISSUE BRIEF Investing in a Clean Energy Future: Solar Energy Research, Deployment, and Workforce Priorities, August 2021, p. 1, archived at↩︎
  2. Price: Tony Dutzik, Jamie Friedman and Emma Searson, Solar Energy on the Rise: Solar Energy is Rapidly Expanding Across the U.S., Environment America and Frontier Group, 2020, accessed 5 August 2021 at↩︎
  3. Gideon Weissman and Emma Searson, We Have the Power: Realizing Clean, Renewable Energy’s Potential to Power America, Environment America and Frontier Group, June 2021, p. 12, accessed at↩︎
  4. See Methodology for more detail on the definition of big box store used in this report. Many companies could also use other spaces to host solar installations, including parking lots and warehouses.↩︎
  5. See Methodology.↩︎
  6. Emissions reduction equivalent in cars: U.S. Environmental Protection Agency, Greenhouse Gas Equivalencies Calculator, accessed 25 October 2021 at↩︎
  7. U.S. Energy Information Administration, U.S. Electricity Flow, 2020, accessed 18 August 2021 at↩︎
  8. Solar Energy Industries Association, Solar Means Business, accessed 9 August 2021 at↩︎
  9. 12,494.4 megawatts installed as of 2019: Solar Energy Industries Association, Solar Industry Research Data, accessed 17 November 2021 at↩︎
  10. Energy Digital Admin, “Walmart installs solar panels on 60 California stores,” Energy Digital, 17 May 2020, archived at↩︎