Sustainable energy in IT requires two things: use less electricity to run computing and its supporting infrastructure, then supply the remaining demand with cleaner power. For data centers, that means coordinating IT equipment, cooling, electrical systems, measurement and energy procurement—not relying on one technology or a single efficiency score. The right combination depends on the facility, its climate, reliability needs and available energy sources.
What sustainable energy means for IT facilities
This guide focuses on the electricity used by enterprise server rooms, colocation facilities and hyperscale data centers. They share efficiency and clean-energy goals, but differ in scale, equipment, operating constraints and access to infrastructure. A measure that suits a large campus may not be practical in a small server room.
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The U.S. Department of Energy and National Renewable Energy Laboratory caution that no single design guide can prescribe the most energy-efficient data-center design for every scenario. Their data-center design guidance treats energy efficiency as a set of connected opportunities, from IT equipment and airflow to cooling, electrical systems, heat recovery and benchmarking.
Why data-center electricity demand matters
The International Energy Agency (IEA) estimates that data centers worldwide used about 415 terawatt-hours (TWh) of electricity in 2024, roughly 1.5% of global electricity consumption. In its 2025 base case, the IEA projects global data-center electricity use could reach about 945 TWh in 2030. That is a scenario projection, not a measured outcome or a guaranteed forecast; the IEA notes substantial uncertainty in demand estimates and projections. AI and accelerated servers are important drivers, but adoption, efficiency and infrastructure constraints will influence the result. See the IEA’s analysis of energy demand from AI and its 2025 executive summary.
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For a separate U.S. historical estimate, the Department of Energy’s Federal Energy Management Program (FEMP) reports that U.S. data centers used approximately 176 TWh in 2023, about 4.4% of total U.S. electricity use. This is a different geography and year from the IEA’s global 2024 estimate, so the figures should not be read as a direct comparison. FEMP’s 2025 fact sheet describes the estimate and DC Pro, an early-stage assessment tool.
How to reduce the electricity needed by IT and facilities
Start by finding where electricity is being used and whether the equipment is doing useful work. Improvements to IT utilization and operating conditions can reduce both computing demand and the downstream load on cooling and electrical systems. DOE/FEMP’s design guide organizes efficiency across these interdependent systems.
Review IT equipment and server operation
Assess whether servers and other IT equipment are being used effectively, and review power-management settings before adding capacity. ENERGY STAR describes operational practices such as server power management in its examples of ways to cut data-center energy waste. Treat example savings as examples, not as a guaranteed result for another facility: outcomes depend on the equipment, workload and implementation.
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Improve airflow before increasing cooling
Hot and cold air mixing, blocked inlets or poorly managed airflow can make cooling systems work harder. Review containment and air distribution, check for obstructions, and use monitoring to identify hot spots before changing temperature or airflow settings. ENERGY STAR’s airflow and HVAC guidance outlines operational approaches. Any change must keep equipment within its thermal operating limits.
Match cooling to the site and climate
Cooling is not a fixed share of data-center electricity. The IEA reports it accounts for about 7% of electricity use in efficient hyperscale data centers and more than 30% in less-efficient enterprise data centers. Those figures describe different facility types and efficiency levels; they are not a universal target or a prediction for a particular site. Climate, equipment density and system design all affect which cooling measures make sense.
Where local climate and operating requirements allow, evaluate free cooling and other ways to reduce mechanical cooling. Also examine fans, pumps and control systems as part of the cooling load. DOE/FEMP prioritizes efficient systems and dry heat rejection where possible, but these approaches are site-dependent rather than universal prescriptions.
Check UPS and other electrical systems
Review uninterruptible power supply (UPS) operation and electrical distribution as part of an efficiency assessment, while preserving the required resilience and power quality. A metered rack power distribution unit (PDU) can help an operator observe rack-level electricity use; it is a measurement aid, not an efficiency improvement by itself. The DOE/FEMP guide covers electrical systems alongside measurement and benchmarking.
Consider heat reuse where there is a real nearby use
Waste heat may be useful when a nearby building, process or district heating network can accept it at the right temperature and time. Assess distance, demand profile, infrastructure and operating economics before treating heat reuse as a project opportunity. Without a suitable heat user, recovering heat does not by itself deliver a practical energy benefit.
How to measure whether changes are working
Establish a baseline before making changes, then use consistent measurements and benchmarking to track results. Power Usage Effectiveness (PUE) is useful for understanding facility overhead: it compares total data-center energy with energy delivered to IT equipment. It can help reveal whether supporting infrastructure is becoming more efficient, but it does not measure every environmental impact or explain whether IT energy is being used productively.
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DOE/FEMP guidance also identifies Energy Reuse Effectiveness (ERE), Water Usage Effectiveness (WUE) and Carbon Usage Effectiveness (CUE) as relevant measures. Consider energy, water and carbon together where they apply: a cooling decision can affect water use, while the carbon impact of electricity depends on its source and timing. No single score establishes that a facility is sustainable. The DOE/FEMP guide describes measurement and benchmarking as part of a broader design and operating approach.
For facilities that need a structured starting point, FEMP’s 2025 fact sheet describes DC Pro as an early-stage assessment tool. Use its output as a way to identify areas for investigation, not as a substitute for site-specific engineering or ongoing measurement.
How to supply the remaining load with cleaner electricity
After reducing avoidable demand, evaluate how the remaining electricity can be supplied with lower-carbon resources. The U.S. Department of Energy’s Office of Electricity identifies solar, land-based wind, battery storage and energy efficiency as rapidly scalable options for meeting data-center demand. It also points to geothermal and nuclear power as potential sources of clean firm power. These are options to assess, not a universal ranking or a guarantee of availability at a given site. See DOE’s overview of clean energy resources for data centers.
Best Value
| Approach | What it contributes | What to assess |
|---|---|---|
| On-site solar or wind | Generation at or near the facility, subject to local resource and project conditions | Available space and resource, connection requirements, output timing and how the facility will cover periods without generation |
| Grid-region clean-energy procurement | A way to support or procure cleaner electricity from resources connected to the relevant grid region | Regional availability, procurement terms, timing of generation relative to load and how the claimed supply is accounted for |
| Battery storage | Can shift electricity availability across time when paired with generation or grid supply | Charging source, operating schedule, duration needed, reliability role and whether charging adds to electricity demand at other times |
| Geothermal or nuclear power | Potential clean firm-power contributions identified by DOE | Whether a project or supply is accessible, its timing, connection and contractual arrangements, and site-specific reliability needs |
These approaches can be combined, but their value depends on when electricity is generated and consumed, the grid region, reliability requirements and project timing. Storage shifts electricity across time; it does not create energy. Keep energy efficiency in the plan as well as clean supply: reducing demand can lower the amount of new generation and infrastructure a facility needs.
How to choose measures for a specific site
Compare candidate projects using the same practical questions rather than assuming one measure is best everywhere:
- Energy reduction: What load is expected to change, and how will the result be measured against a baseline?
- Reliability and thermal limits: Does the change preserve redundancy, power quality and safe equipment operating conditions?
- Site and climate fit: Are the necessary space, climate, grid connection, heat user or energy resource available?
- Water and carbon: How might the measure affect water demand and emissions associated with electricity supply?
- Timing and delivery: When does energy become available relative to the facility’s demand, and how long will implementation take?
- Cost and operations: What capital, operating and maintenance requirements need to be evaluated for this site?
- Measurement: Can the facility verify the change with consistent data after implementation?
The sources do not establish a universal ranking or payback period for these measures. An operator should compare proposals against the facility’s baseline, constraints and objectives.
Quick Recap
A practical sequence for an energy-efficiency program
- Define the boundary. Identify which buildings, IT loads and supporting systems are included, and distinguish the facility’s own energy data from grid-region procurement or generation claims.
- Build a baseline. Gather consistent readings for IT and facility electricity, then choose relevant measures such as PUE and, where appropriate, ERE, WUE and CUE.
- Investigate operational opportunities. Review server power management, utilization, airflow, HVAC controls, fans and pumps, UPS operation and electrical distribution.
- Evaluate site-dependent projects. Check whether free cooling, dry heat rejection, heat reuse, on-site generation or storage is feasible under the site’s climate, thermal limits, infrastructure and demand profile.
- Set an implementation and verification plan. Define the expected change, reliability safeguards, responsible teams and measurement method before work begins; compare results with the baseline after commissioning.
- Plan cleaner supply for the residual load. Assess grid-region procurement and available generation or firm-power options in light of energy timing, reliability, water and carbon considerations.
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