AI Data Centres Could Erase 15 Years of US Power-Sector Emission Cuts

October 29 — According to a Bloomberg report on the evening of 28 October, an internal analysis by the US environmental group the Sierra Club finds that the rush to build fossil fuel plants to power AI data centres could wipe out the greenhouse gas cuts the US power sector has made over the past 15 years.

The Sierra Club estimates that, counting planned AI projects, US power-sector carbon dioxide emissions will reach 2.1 billion tonnes by 2030 — 618 million tonnes more than in 2025, a rise of about 42%.

Jeremy Fisher, the Sierra Club’s chief climate and energy adviser, notes that a forecast made 18 months ago would have put the build-out and its impact at only a quarter to a half of current projections.

Faced with the enormous power demand of AI data centres, many developers are turning to natural gas, both drawing on the public grid and building their own generation.

By 2030 most of the added emissions are expected to come from facilities not directly connected to the public grid. Tech companies often build their own power to avoid long waits for grid connections. Fisher says this share could exceed 460 million tonnes — roughly Mexico’s annual emissions.

BloombergNEF analyst Helen Kou notes that if new facilities rely heavily on gas-fired generation, emissions are likely to come in higher than this year’s level.

How much higher remains hard to judge. Forecasts for the US power sector diverge enormously — the gap between the highest and lowest estimates corresponds to more generation than California and Florida consume combined.

The Sierra Club analysis combines public filings with other organisations’ data centre forecasts, including the Environmental Integrity Project’s tally of plants planned before 2030 and their emissions.

New generating units connected to the public grid alone would lift 2030 emissions 10% above the baseline scenario, or 154 million tonnes. On top of that come the power facilities data centres build for themselves.

A separate analysis by the environmental groups Earthjustice and the Better Data Center Project finds that 80% of the energy for such facilities could come from natural gas. On-site plants add local air pollution and greenhouse gases, and they are fuelling opposition to data centre construction across the US.