A data centre uses power every hour of every day. Solar panels produce only in daylight, and wind turbines only when the wind blows. So a data centre can buy as much renewable energy as it uses over a year and still run on other sources at night or on still days. Running on clean power every hour needs more: storage, a mix of sources in different places, and contracts that match supply and demand hour by hour.
The gap between supply and demand
The US Department of Energy notes that solar energy production can be affected by season, time of day, clouds, dust and haze, and that solar energy is not always produced at the time energy is needed most. Storage helps: short-term storage that lasts just a few minutes keeps a solar plant running smoothly, while longer-term storage can help provide supply over days or weeks. NREL adds that variability can be managed cost-effectively by increasing grid flexibility, including with energy storage and other quick-ramping resources.
Annual matching and hourly matching
Many companies buy renewable energy equal to their annual use. Google, explaining why it set a goal to source carbon-free energy to match its electricity consumption in all places, at all times, calls annual matching an imperfect solution. Measured hour by hour, it reported that one of its data centres was 67% matched with carbon-free sources in 2017, and that none of its data centre campuses were matched 24x7 that year. Google now publishes an hourly carbon-free energy share for each cloud region, and in its 2025 data gives, for example, 83% for its Oregon region and 70% for Frankfurt.
| Approach | What it means | What it leaves |
|---|---|---|
| Annual matching | Buy clean energy equal to a year of use | Hours with no sun or wind are met by the grid mix |
| Hourly matching | Match clean supply to use in each hour | Needs storage, firm clean power and a wider mix |
| On-site solar or wind | Generate at the data centre | Usually far smaller than a large data centre's demand |
Where data centres get their power today
The International Energy Agency estimates that renewables, primarily wind, solar PV and hydro, currently supply about 27% of the electricity used by data centres worldwide, natural gas 26% and nuclear 15%. It projects that renewables meet nearly half of the additional demand over the next five years, growing from 460 TWh in 2024 to over 1,000 TWh in 2030.
What is not certain
- Hourly matching results depend heavily on the local grid; figures for one region do not carry over to another.
- Company figures on clean energy matching are self-reported.
- IEA projections are scenarios, not forecasts of what any one data centre will use.
Sources and method
- US Department of Energy, Solar Energy Technologies Office, Solar Integration: Solar Energy and Storage Basics, updated 31 March 2025. https://www.energy.gov/eere/solar/solar-integration-solar-energy-and-storage-basics
- NREL, Renewable Energy Integration, updated 22 May 2025. https://www.nrel.gov/grid/renewable-energy-integration
- Google, 24x7 carbon-free energy, September 2019. https://sustainability.google/projects/24x7
- Google Cloud, Carbon free energy for Google Cloud regions, 2025 data, updated 26 October 2026. https://cloud.google.com/sustainability/region-carbon
- International Energy Agency, Energy and AI, chapter Energy supply for AI, April 2025 (no date shown on the page). https://www.iea.org/reports/energy-and-ai/energy-supply-for-ai
Method: each link was opened on 29 October 2026 and every figure was taken from the page cited beside it. No figure was estimated.
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This article provides general information, not investment advice or an offer of securities.