Gartner warns that fossil fuel dominance in on-site power generation is not sustainable, given the rapid rise in datacenter energy consumption due to AI servers.

The research firm forecasts that electricity required by datacenters worldwide is set to expand 16 percent this year alone, and likely to double to 980 terawatt hours (TWh) by 2030.

It will come as little surprise to El Reg readers that the rapid rise of AI-optimized servers and infrastructure is the chief culprit fueling the increase. Gartner expects the electricity usage from all that machine learning gear to rise nearly fivefold, from 93 TWh in 2025 to 432 TWh in 2030.

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This sharp rise means that AI infrastructure will account for more and more of the total consumption, expanding from about 21 percent of total bit barn power use this year, to 44 percent of it by the end of the decade. At this point, those AI servers will represent 64 percent of incremental demand, meaning the additional electricity required to power new systems added to the grid.

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But the frenetic pace of datacenter building compared with the glacial pace of power grid expansion means that many facilities face a long wait to get connected, and operators are increasingly turning to on-site generation, at least in the short term. This likely means burning extra fossil fuels that add to pollution and greenhouse gas emissions.

The Colossus datacenter operated in Tennessee by Elon Musk's xAI has faced criticism for allegedly belching out [4]smog-causing fumes from its gas turbines, for example. Meanwhile, [5]coal-fired power stations have seen an unexpected resurgence in the US due to bit barn energy requirements.

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Gartner states that the current dominance of fossil fuels in on-site power generation is not sustainable, and that cleaner on-site power alternatives such as green hydrogen, geothermal, and small modular reactors (SMRs) will become viable fuel alternatives for datacenter microgrids by the end of the decade.

"In the near term, natural gas will lead as the main power source for datacenters," [7]said Gartner VP analyst Tony Harvey. "However, within the next three to five years, we anticipate rapid growth in battery energy storage systems (BESS) to balance the fluctuations of solar and wind energy."

[8]Brits to help foot power bill for datacenters under government AI plans

[9]Power: The answer to and source of all your AI datacenter problems

[10]Britain's first small modular reactors to be built in Wales

[11]Microsoft is building datacenter superclusters that span continents

Financial analyst biz Jefferies recently published a report that BESS could become standard at datacenters thanks to the AI infrastructure boom, and [12]forecast that 20 GW of capacity will be deployed over the next decade .

Another recent study estimated that [13]renewable energy sources could power datacenters at a lower cost than relying on nuclear generation from SMRs, which other analysts believe are [14]likely to be a decade away from coming into production.

Meanwhile, [15]geothermal microgrids offer great promise, according to Gartner, but the high initial costs and permitting challenges will likely keep it a niche option for the present. ®

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[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/aiml&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aRz6h2AMIC9ZKVSh0rs8TQAAAFQ&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0

[4] https://www.theregister.com/2025/06/02/naacp_musk_dc/

[5] https://www.theregister.com/2025/10/10/datacenter_coal_power/

[6] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/aiml&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aRz6h2AMIC9ZKVSh0rs8TQAAAFQ&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0

[7] https://www.gartner.com/en/newsroom/press-releases/2025-11-17-gartner-says-electricity-demand-for-data-centers-to-grow-16-percent-in-2025-and-double-by-2030

[8] https://www.theregister.com/2025/11/18/uk_ai_growth_zones/

[9] https://www.theregister.com/2025/11/15/power_supercomputing/

[10] https://www.theregister.com/2025/11/13/anglesey_smr/

[11] https://www.theregister.com/2025/11/13/microsoft_fairwater_dataceter_superclusters/

[12] https://www.theregister.com/2025/11/11/analysts_forecast_bit_barn_battery/

[13] https://www.theregister.com/2025/09/26/renewables_vs_smr_datacenter/

[14] https://www.theregister.com/2025/11/13/anglesey_smr/

[15] https://www.theregister.com/2025/03/13/geothermal_datacenters/

[16] https://whitepapers.theregister.com/