Microsoft’s annual pollution to skyrocket 44% from single off-grid gas-powered project in WV; full 8GW project adds equivalent of 6 million cars to highway, according to new analysis

SAN FRANCISCO (Chochenyo and Karkin Ohlone Lands) — Researchers at Stand.earth Research Group (SRG) have calculated that a single new Microsoft data center facility announced last week in West Virginia is anticipated to unleash a 44% increase in the company’s annual emissions. The SRG analysis independently verifies and builds on methodology recently published by journalist and analyst Michael Thomas. This new analysis also finds that the fully gas-powered, off-grid (or “behind-the-meter”) facility will burn enough methane gas to power over 1.2 million homes in West Virginia.

Microsoft’s facility will be just one part of this off-site data center complex, and further analysis reveals that upon reaching its full planned 8GW capacity in 2031, Microsoft and co-located partners will emit 25.55 million metric tons of CO₂e per year, as much as putting nearly 6 million cars on the road.

Operating at a 90% capacity factor – common for high-utilization AI training – Microsoft’s 1.35  gigawatt (GW) facility will require approximately 81.25 trillion Btu of methane gas every year, based on the official electrical efficiency of the CAT G3500 at 44.7%. Using the carbon intensity of methane gas, this project would emit roughly 4.31 million metric tons of CO₂e per year. To achieve this scale with the CAT G3500 series (rated at ~1.15 MW per unit), approximately 2,000 generators would be required.

Microsoft is one of a number of hyperscale data center developers that have publicly committed to reducing their carbon emissions, setting the goal in 2020 to become “carbon negative” and to power its data centers with round-the-clock, carbon-free energy by 2030.

“In the rush to bring data centers online, hyperscalers like Microsoft are essentially abandoning their pledges to protect the climate and do right by communities. You can’t claim to be a leader on climate and then build out massive fossil-fuel facilities that emit millions of tons of climate pollution and poison the people living next door,” said Rachel Kitchin, Senior Corporate Climate Campaigner at Stand.earth.

 

This announcement is part of a growing trend of hyperscalers increasingly turning to on-site power generation to get data centers online more quickly. On-site generation is overwhelmingly coming from methane gas power, drastically increasing fossil fuel lock-in: At the end of 2024, on-site data centers made up 5% of all demand for methane gas power being developed in the U.S. One year later, this has ballooned to 39%, with on-site data center demand for methane gas capacity in 2025 outstripping all demand for methane gas capacity in the prior year.

Developers claim that the behind-the-meter approach will “eliminat[e] the burden on existing utility customers and protect[-] ratepayers’ bills.” However, the rapid growth in demand from the data center build out has already drastically increased consumers’ electric bills and is likely to continue to do so moving forward by spiking methane gas prices, according to industry analysts.

“By prioritizing methane gas as the primary power source for data centers, hyperscalers are throwing a lifeline to the fossil fuel industry and putting communities in grave danger, while putting the final nail in the coffin of their own climate commitments. To keep communities and the climate safe, data centers must be run on 24/7, local and additional renewable energy from the beginning, or simply not run at all,” said Kitchin.

 

The behind-the-meter methane gas build out also comes with its own set of negative externalities. Because these facilities are often using smaller, less-efficient gas turbines, they have greater consequences for the climate – and people living nearby. A Virginia Commonwealth University study published earlier this month found that on-site power derived from methane gas and diesel generators for a single data center in Virginia could lead to $53-99 million in health-related costs.

Communities living near fossil fuel power, off-grid or otherwise, face increased risk of cancers, heart disease, stroke, respiratory illnesses, and other adverse health outcomes. A 2021 Harvard University study found that 1 in 5 deaths globally can be linked to air pollution caused by the burning of fossil fuels, reinforcing the industry’s responsibility for rapid climate action.

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Media contact: Shane Reese, Corporate Campaigns Media Director, Stand.earth, shane.reese@stand.earth, +1 919 339 3785 (U.S. Eastern Time)