AI is testing Big Tech’s climate pledges. Microsoft’s 2025 report showed total emissions 23.4% above its 2020 baseline even as operational (Scope 1+2) emissions fell 29.9%, because data center construction and hardware pushed supply-chain emissions up 26%. The IEA estimates data centers caused about 180 Mt CO2 in 2024 and could peak near 320 Mt around 2030. Companies are buying clean power at record pace: Google contracted over 12 GW in 2025 alone, and tech firms signed about 40% of corporate renewable PPAs. On water, US data centers used about 17 billion gallons directly in 2023 (LBNL); Google replenished roughly 78% of its freshwater consumption in 2025. The EU now requires sites above 500 kW to report energy, water and renewable KPIs.
Data center sustainability covers three linked problems: the carbon emitted to power and build facilities, the water used to cool them, and whether the clean energy they buy actually matches their consumption hour by hour. This article reviews what the largest operators report, what 24/7 carbon-free energy means, how water pledges work, and what new EU rules require. It is part of our Data Center Economy hub; for the nuclear contracts underpinning many clean energy plans, see nuclear power for data centers, and for the cooling technologies that drive water use, read data center cooling explained.
Are Big Tech emissions rising because of AI?
For several companies, yes. Microsoft’s total emissions were 23.4% above 2020 levels in FY24, driven by data center construction and hardware in its supply chain, even though its operational emissions fell.
What is 24/7 carbon-free energy?
It means matching every hour of electricity consumption with carbon-free supply on the same grid, rather than buying enough renewable energy over a year to equal annual use. Google targets it for 2030.
How much water do data centers use?
LBNL estimated US data centers used about 17 billion gallons directly in 2023, plus about 211 billion gallons indirectly through electricity generation. Closed-loop cooling can cut direct use sharply.
How much carbon do data centers emit?
The IEA estimates data centers were responsible for about 180 million tonnes of CO2 in 2024 from the electricity they used, roughly 0.5% of global fuel combustion emissions. In its base case, emissions rise to a peak near 320 Mt around 2030 before easing to about 300 Mt by 2035.
Those figures come from the IEA’s Energy and AI report, which also estimated data center electricity use at about 415 TWh in 2024, around 1.5% of global consumption, and projected it could roughly double to about 945 TWh by 2030. The IEA’s 2026 follow-up said demand rose 17% in 2025. More detail is in our data center electricity consumption statistics.
Why don’t emissions double along with electricity? Because the IEA expects renewables to meet nearly half of the growth in data center demand to 2030, with natural gas and coal together covering more than 40%, and nuclear’s role growing after 2030. In a faster-growth “Lift-Off” case, data center emissions rise about 2.5 times over the decade. The IEA also notes that AI applications could, under favourable conditions, reduce emissions elsewhere in the economy by more than data centers emit, though it stresses those savings are not assured.
These IEA numbers count only electricity-related emissions. They exclude backup diesel generators, refrigerant leaks and, importantly, the embodied carbon in concrete, steel and the servers themselves, which for hyperscalers is now often the fastest-growing part of their footprint.
Why are Big Tech emissions rising despite clean energy pledges?
Emissions are rising mainly because building data centers and manufacturing chips and servers create large supply-chain (Scope 3) emissions that clean electricity purchases cannot offset. Microsoft’s operational emissions fell almost 30% versus 2020, but its total emissions were 23.4% higher.
Microsoft’s 2025 Environmental Sustainability Report, covering fiscal 2024, put Scope 1 and 2 emissions 29.9% below its 2020 baseline, reflecting large clean electricity purchases, while Scope 3 emissions were 26% higher and total emissions 23.4% higher. The company attributes much of the Scope 3 increase to data center construction and the hardware it fills them with. Microsoft remains committed to being carbon negative by 2030, and has leaned heavily on carbon removal: nearly 30 million tonnes contracted under long-term agreements by the time of the 2025 report, about 22 million of them in fiscal 2024 alone. Its 2026 report added deals including 5.08 million tonnes of permanent removal from Stockholm Exergi and up to 18 million tonnes of nature-based credits through Rubicon Carbon.
Google’s trajectory has been similar. Its 2024 Environmental Report said total greenhouse gas emissions rose 13% in 2023, largely due to data center energy use and supply chain emissions. Google has since emphasized efficiency gains and record clean energy procurement, but has acknowledged that AI growth makes its 2030 targets harder to reach.
The structural problem is that capital spending is accelerating. The IEA notes that capex by five large technology companies exceeded $400 billion in 2025 and was set to rise another 75% in 2026, as covered in our article on the AI capex supercycle. Each new campus embeds tens of thousands of tonnes of concrete and steel, plus servers with high-carbon semiconductor supply chains. Low-carbon concrete, recycled steel and longer server lifetimes help, but cannot yet offset the sheer pace of construction.
What is 24/7 carbon-free energy and how does it differ from 100% renewable matching?
Annual renewable matching means buying enough renewable energy over a year to equal total consumption. 24/7 carbon-free energy (CFE) means every hour of consumption is met by carbon-free supply on the same grid, which is far harder because it requires clean power at night and in calm weather.
Most large operators already claim the first standard. Amazon says it matched 100% of the electricity used across its global operations with renewable energy in 2025, for the third consecutive year, years ahead of its original 2030 target. Microsoft reported reaching its milestone of matching 100% of annual electricity consumption with renewables in fiscal 2025. Meta has also matched its operations with clean and renewable energy and says the wind and solar projects it has supported add almost 29 GW to grids.
Critics argue annual matching overstates climate benefits, because a data center running on gas-heavy grid power at night can still claim 100% renewable status by buying surplus solar certificates generated at noon elsewhere. 24/7 CFE closes that gap. Google committed to run on carbon-free energy every hour on every grid where it operates by 2030, and Microsoft has a goal it calls 100/100/0: 100% of electricity, 100% of the time, from zero-carbon sources, also by 2030.
Reaching hourly matching drives a different procurement strategy: more firm clean power such as nuclear, geothermal and hydro, more storage, and sometimes flexible computing that shifts workloads to hours and places where clean power is abundant. That logic explains why the same companies leading 24/7 commitments are signing nuclear restart and SMR deals, and why the IEA counts about 45 GW of conditional SMR offtake agreements with data center operators.
How are tech companies buying clean energy for data centers?
Mainly through long-term power purchase agreements (PPAs) for new wind, solar and storage, increasingly supplemented by nuclear, geothermal and utility green tariffs. The IEA estimates the tech sector signed about 40% of corporate renewable PPAs in 2025.
The volumes are enormous. Google says it signed more than 12 GW of net-new clean energy agreements in 2025, its largest annual total, bringing it to nearly 35 GW across more than 240 agreements since 2010. Microsoft said in its 2025 report that it contracted 19 GW of new renewable energy across 16 countries in 2024 and had contracted 34 GW of carbon-free electricity across 24 countries overall. Meta reports almost 29 GW of supported wind and solar.
PPA structures have evolved. Virtual PPAs, in which the buyer pays a fixed price and receives certificates while the project sells into the market, dominate in the US. Physical PPAs and utility green tariffs are more common where markets are regulated. Increasingly, buyers sign deals for firm resources: existing nuclear output, restarts such as Crane and Duane Arnold, geothermal, and battery-backed solar.
There is a tension, though. Data centers are increasingly being powered in the near term by natural gas, including on-site turbines, because grid connections are slow. The IEA’s 2026 report counted a pipeline of about 47 GW of on-site gas power projects for US data centers. Behind-the-meter gas can be paired with carbon capture or later replaced with cleaner supply, but in the short term it adds direct emissions that annual certificate purchases do not erase, as discussed in our article on the {L(‘data-center-power-grid-bottleneck’,’data center power bottleneck’)}.
| Company | Emissions trend (latest reported) | Clean energy procurement | Water | Key 2030 goal |
|---|---|---|---|---|
| Microsoft | Total +23.4% vs 2020; Scope 1+2 −29.9% (FY24) | 34 GW contracted; 100% annual renewable match (FY25) | Replenished 14.2m m³ in FY25, above withdrawals; WUE 0.30 L/kWh | Carbon negative; water positive |
| Total +13% in 2023 (2024 report) | 12+ GW in 2025; ~35 GW since 2010 | Replenished ~7.7bn gallons, ~78% of freshwater use (2025) | Net zero; 24/7 CFE | |
| Meta | Targets −42% Scope 1+2 by 2031 vs 2021 | ~29 GW wind and solar supported | Restored 1.6bn gallons in 2024 | Net zero value chain; water positive |
| Amazon | Carbon intensity −38% since 2019 | 100% annual renewable match (2025) | AWS 75% toward water positive (end-2025) | AWS water positive; net zero by 2040 |
Source: Microsoft 2025 and 2026 Environmental Sustainability Reports; Google 2024 and 2026 Environmental Reports; Meta 2025 Sustainability Report; Amazon Sustainability (2025 data); IEA.
How much water do data centers use, and what are water-positive pledges?
US data centers used about 17 billion gallons of water directly in 2023, according to Lawrence Berkeley National Laboratory, plus about 211 billion gallons indirectly through power generation. Water-positive pledges promise to replenish more water than a company consumes, usually by 2030.
Company disclosures show the scale. Google reported more than 6 billion gallons of data center water use in 2023, and Meta about 776 million gallons. LBNL projected direct water use by hyperscale facilities could reach 16 to 33 billion gallons a year by 2028. In Virginia, JLARC found data centers used about 2.1 billion gallons in 2023, up 86% since 2019, with roughly one-third from reclaimed water. Our article on data center water, land and jobs statistics has more local data.
Microsoft, Google, Meta and AWS all target being water positive by 2030. Progress varies: Google says it replenished about 7.7 billion gallons in 2025, roughly 78% of its freshwater consumption, through 165 projects across 97 watersheds; AWS says it was 75% of the way to water positive at the end of 2025; Microsoft reported replenishing more than 14.2 million cubic metres in fiscal 2025, more than it withdrew; and Meta says its restoration projects returned over 1.6 billion gallons to stressed regions in 2024.
Replenishment is not the same as reducing local consumption. A company can fund wetland restoration in one basin while drawing heavily on an aquifer in another. That is why siting and cooling technology matter. Microsoft’s design for new data centers, announced in December 2024, uses closed-loop chip-level cooling that does not evaporate water for cooling and is expected to avoid more than 125 million litres a year per facility, with pilots in Phoenix and Mount Pleasant, Wisconsin.
What does the EU require data centers to report?
Under the EU Energy Efficiency Directive and Delegated Regulation 2024/1364, data centers with at least 500 kW of installed IT power must report energy, water, waste heat and renewable energy data to a European database every year. The Commission proposed a common rating scheme in September 2026.
The first reports were due by 15 September 2024, and subsequent reports by 15 May each year, covering the previous calendar year. Required indicators include total and IT energy consumption, total and potable water input, waste heat reused, renewable energy consumption (split into guarantees of origin, PPAs and on-site generation), and data traffic and capacity figures. From these, four sustainability indicators are derived: power usage effectiveness (PUE), water usage effectiveness (WUE), energy reuse factor (ERF) and renewable energy factor (REF).
The next phase is about performance, not just disclosure. The European Commission proposed a common EU rating scheme for data centers on 21 September 2026 to make energy and water performance comparable, ran a consultation on minimum performance standards through December 2026, and plans a legislative proposal on those standards in the second quarter of 2027. At the same time, the EU says it aims to triple its data center capacity, a goal that will test how well efficiency rules and growth ambitions coexist. Our overview of Europe data center investment covers the growth side.
Some jurisdictions go further: Germany’s Energy Efficiency Act sets efficiency and renewable requirements, and Singapore requires new data centers to meet a PUE below 1.3.
Can AI data centers ever be truly sustainable?
They can become much cleaner, but not without trade-offs. Efficiency gains, hourly clean power matching, closed-loop cooling and low-carbon construction can cut footprints sharply, yet the speed of AI growth means absolute emissions and water use are likely to keep rising through the late 2020s.
The optimistic case rests on several trends. Hardware is becoming more efficient per unit of computation: Google says its eighth-generation TPUs deliver up to twice the performance per watt of the previous Ironwood generation. Hyperscale facilities already run at PUEs around 1.1 to 1.2, far better than the industry average of about 1.54 reported by Uptime Institute. Clean firm power from nuclear restarts, uprates and geothermal is arriving this decade, and the IEA’s analysis suggests AI applications could deliver emissions savings in other sectors larger than data centers’ own emissions.
The sceptical case notes that efficiency gains have historically been outpaced by demand growth, that behind-the-meter gas is expanding quickly, and that corporate targets rely increasingly on carbon removal and replenishment rather than absolute cuts. Embodied emissions in construction and chips remain hard to abate. Both cases agree that location and procurement matter: a data center on a clean grid with closed-loop cooling has a fundamentally different footprint from one on a coal-heavy grid using evaporative towers. That is why sustainability is now a core part of data center site selection.
What should companies watch in data center sustainability over the next two years?
Watch three signals: whether hyperscalers’ total emissions start falling as clean firm power arrives, whether EU minimum performance standards set binding PUE or water limits, and whether US regulators or investors begin demanding hourly or location-based emissions reporting.
Other indicators include the pace of nuclear restarts and SMR licensing, adoption of closed-loop cooling in water-stressed regions, growth of low-carbon concrete and steel in construction, and the extent to which on-site gas plants incorporate carbon capture or are replaced over time. Corporate reports published in mid-2027, covering 2026, will show whether record clean energy contracting has begun to bend emissions curves or whether AI construction continues to overwhelm them.
For now, the honest assessment is that data center sustainability is improving per unit of computing but worsening in absolute terms at several major operators. Whether that reverses before 2030 will depend less on new pledges than on how quickly clean firm power, efficient cooling and low-carbon materials can be deployed at the scale of the AI build-out.
Frequently Asked Questions
What is the difference between Scope 1, 2 and 3 emissions for data centers?
Scope 1 covers direct emissions, such as diesel backup generators and on-site gas turbines. Scope 2 covers emissions from purchased electricity. Scope 3 covers everything else in the value chain, including construction materials and server manufacturing. For hyperscalers, Scope 3 is now usually the largest and fastest-growing category, which is why Microsoft’s total emissions rose even as Scope 1 and 2 fell.
Is buying renewable energy certificates enough to make a data center green?
Not on its own. Annual certificate matching can claim 100% renewable status while the data center still draws fossil power at night or during calm periods. Hourly 24/7 carbon-free energy matching, additional new clean generation on the same grid, and location-based emissions reporting give a more accurate picture. Google and Microsoft both target hourly matching by 2030.
Which data center cooling method uses the least water?
Closed-loop liquid cooling paired with dry coolers or chillers uses the least on-site water because it avoids evaporation. Microsoft says its zero-evaporation design avoids more than 125 million litres a year per facility. The trade-off is slightly higher electricity use on hot days. Evaporative cooling uses less energy but much more water, which is a problem in drought-prone regions.
Do EU rules apply to non-European data center operators?
Yes, if they operate data centers in the EU. The reporting obligation applies to each facility in an EU member state with installed IT power of at least 500 kW, regardless of the owner’s nationality. Hyperscalers, colocation providers and enterprises with qualifying sites must submit energy, water, waste heat and renewable energy data annually to the European database.
Discover more from Kurums | Business Intelligence
Subscribe to get the latest posts sent to your email.