Can big-box stores do big things for our environment? We tend to bristle at Walmart’s sheer immensity and its domination of local economies. But on the environmental front, the company claims that the “size and scale” of its operation can be wielded to drive green-energy development—saying that slapping solar panels on hundreds of supercenter rooftops could add up to some serious juice. But environmentalists warn that, despite Walmart’s potential big green footprint, its “green growth” business model prioritizes profits over the environment, the same way its mass retail model pushes low prices at the expense of workers.

Walmart recently set a target of transitioning to a 100 percent renewable energy supply, primarily through improvements in energy efficiency, and through wind, solar and other clean-energy projects, attaining “the production or procurement of 7 billion kilowatt hours of renewable energy globally” by the end of 2020. However, a study by the Institute for Local Self Reliance (ILSR) finds that Walmart’s green agenda is blighted by ongoing reliance on dirty fuels. According to ILSR’s analysis, “Walmart’s U.S. operations use nearly six times the amount of electricity as the entire U.S. auto industry. The operations use more than 4.2 million tons of coal each year, accounting for nearly 75 percent of the company’s total emissions from U.S. electricity use.”

Since Walmart launched its push for renewables in 2005, its carbon emissions have grown 14 percent; its renewable power usage actually peaked in 2011 and then slid back. So despite mounting international pressure to curb carbon consumption, Walmart has actually pulled back from its earlier promises to lead the retail industry in sustainable business practices.

The ILSR argues that in terms of converting incrementally to renewable energy sources, Walmart lags behind other major retailers, including Kohls and McDonald’s. Staples US, for example, claims that it has “increased…green power purchases to cover 100 percent of our U.S. electricity needs.” Though it’s hard to make a direct comparison, Walmart’s mammoth retail operations seem far more carbon intensive.

According to Walmart spokesperson Tara Greco, “In the U.S., as of 2013, Walmart-driven renewable energy projects provided three percent of our buildings’ annual electricity needs, and the grid provided another 11 percent for a total of 14 percent renewable electricity in the U.S.” Globally, Walmart reports that about 19 percent of energy use in its buildings comes from renewable sources, primarily wind power.

Walmart’s reliance on coal-based power not only drives up carbon emissions but also results in localized air and water pollution. Toxics emanating from coal-fired power plants disproportionately hurt the environmental health of poor communities of color, who also happen to be a target customer base for Walmart.

And Walmart’s use of renewables vary highly by region. According to ILSR, “Over 90 percent of Walmart’s clean energy—including both its on-site installations and its purchases of renewable power—is produced and consumed in places where coal comprises a smaller than average share of the power Walmart’s stores are pulling from their local grid region.” So Walmart typically concentrates green investments in places that are less coal-dependent than Walmart itself. Likewise, Walmart stores in coal-heavy regions generally invest far less in renewables.

Walmart also fuels dirty energy through the political machine, providing financial support to politicians strongly allied to the fossil fuel industries, according to campaign records.

Walmart boasts its emissions have remained “steady” overall in relation to its growth since 2005. Over an eight-year period, the company reports it has “limited our emissions growth to only one-quarter…of our business growth” in terms of sales and square footage. In other words, “progress” for Walmart means raising its emissions more slowly than it expands its corporate empire.

So can green capitalism save us? There’s obviously incentive to invest green when, say, installing wind turbines is cost-effective for certain stores. But advocates argue that Walmart is squandering its potential to leverage its market share to overturn (rather than conform to) business-as-usual climate destruction.

And Walmart’s reported emissions may be just the tip of a submerged iceberg. Like other multinationals, when assessing its carbon footprint, Walmart focuses on “Scope 1” and “Scope 2” emissions from buildings, logistical operations and purchased electricity. But ILSR says the data is less clear on the effects of Scope 3 emissions, stemming from indirect energy consumption through waste and “leased facilities.”

Moreover, ILSR Co-Director Stacy Mitchell tells The Nation via e-mail, Walmart does much of its business in a global economic context where, overall, coal consumption is rising, “mainly because of growing coal use in China, where Walmart does most of its manufacturing. Our analysis only captures Walmart’s consumption of coal-fired electricity in the U.S. The company also consumes a lot of dirty coal-fired energy in China. But we don’t know how much.”

Walmart says it is on track to cut global supply-chain emissions by 20 million metric tons from 2010 through 2015. It also recently announced a partnership with China to promote cleaner production, by inviting suppliers of “70 percent of Walmart’s business sourced in China…to participate in an energy efficiency program by the end of 2017.” But the program is voluntary, without overall reduction mandates.

Given Walmart’s reliance on complex global networks of contractors and suppliers, with a trade structure based on outsourcing and offshoring production to poorer countries like China, indirect emissions down the supply chain might be the big unknown we should be really worried about.

In fact, the size of Walmart’s entire scope is itself troubling. Despite claims of “corporate social responsibility,” when any one corporation is allowed to dominate a market—whether its a consumer retail market, or a local job market or the global solar panel market—a massive concentration of power in a single, private entity tends to steer toward a form of stagnation that maintains profits; any semblance of real altruism is just incidental to business gains.

A different path to green energy might wield Walmart’s market clout to build sustainability on more ambitious, comprehensive scale. In an announcement of the report, Jeremy Hays, executive director of Green For All, said “Walmart should…be using its power and wealth to build stronger and more sustainable communities, not disrespecting workers and endangering the future of our planet.” A real plan for sustainability would foster economic development that helps communities transition toward clean energy systems that are socially inclusive and protect environmental health, and provide living-wage jobs. Of course, given the company’s history as a premiere low-wage employer as well as a top carbon emitter, marrying green development with decent work does not seem to be the Walmart way.

It seems that just as Walmart’s low Black Friday prices are underwritten by poverty wages, its big-box environmental agenda just slaps a thin coat of green over a dirty energy system.