With more than 5,000 locations in the US and 10,000 globally, Walmart’s unparalleled size comes with an equally stark carbon footprint. The retail giant emitted 14 million metric tons of greenhouse gasses in 2021, equivalent to the annual emissions of roughly 300,000 average American households. In the transition to renewable energy, Walmart’s energy footprint presents problems and an opportunity.

What are Walmart’s climate commitments?

In 2020, Walmart announced its commitment to net-zero emissions by 2040. More recently, in January 2024, Walmart adopted specific targets to help reach this goal: aiming to complete 10 gigawatts of new clean energy projects by the end of 2030. These plans include adding one gigawatt of new clean energy on-site, primarily through solar and storage.

While other companies have expressed commitment to net zero by 2040–including competitors like Target and Amazon–Walmart is trying to distinguish itself with the speed, transparency, and scale of its efforts. Just two months after detailing their plan, Walmart committed to investing in new clean energy projects totaling nearly 1 GW, the equivalent of the annual power consumption of more than 200,000 average households.

Walmart plans to make these clean energy investments through community projects and agreements to buy power from large-scale solar and wind farms. While these long-term power purchase agreements will grow clean energy in America and reduce the brand’s dependence on fossil fuels, Walmart is missing a big opportunity to produce power right where it’s needed.  

Why rooftop solar?

With more than 780 million combined square feet of rooftop space that could accommodate solar, Walmart is the American retailer with the most rooftop solar potential. These flat, open, and sunny roofs could provide electricity close to where it can be used–reducing energy losses that happen during electricity transmission and distribution. In 2020, these transmission losses made up 6% of gross electricity generation. Especially when coupled with battery storage, producing electricity on-site also has the benefit of making the grid more resilient to outages and disruptions.

Where Walmart has installed solar on its roofs, it has worked. The retailer’s existing solar installations have already saved the company over $1 million, and its installations in California were expected to provide between 20% to 30% of each location’s electricity needs.

From Apple to Exxon, firms are making big decisions about how to approach environmental issues. Walmart shows promise–but there is still a lot of work to do to combat 14 million metric tons of emissions. Rooftop solar offers a readily available, cost-effective, and convenient way for the retail giant to immediately commit to clean energy.