Servers do the computing. Electrical systems deliver and condition power. Cooling systems move heat away. Networks move data. A campus can contain several buildings built in phases, so one announcement is not automatically one operating facility.
Not every data center is the same kind of place. Types of data center explains how a hyperscale campus, colocation, a carrier hotel, an enterprise or government data center and an edge site work and differ.
Explore: follow the power and the heat
Choose a part to see the number it usually produces, where that number is recorded and what it doesn’t tell you. Switch the outdoor cooling to see where the water goes. Moving lines show the direction of flow, not measured amounts.
1Grid connection and substation
Utility lines bring electricity to the site, and a substation steps the voltage down.
- Number you’ll see
- A utility-service request, contracted capacity or service limit, in megawatts (MW): a rate of power at a moment.
- Usually recorded in
- Utility and state utility-commission filings, which can establish requests, contracts or cost-allocation rules.
- What it doesn’t tell you
- How much electricity the site uses. A request, a contract and measured grid load are different numbers, and energy used over time is counted in megawatt-hours (MWh). The physical grid may serve many customers even when a company signs a contract tied to a particular generator.
Read more: power answers · ratepayer brief
2Transformers and switchgear
Transformers, switchgear and power-conditioning equipment step the voltage down, route power and keep it steady for the computing equipment. Battery systems, often called UPS, carry the load through the short gap before backup generators start.
- Number you’ll see
- Equipment ratings, often in kVA or MVA. A rating is what that equipment is built to handle.
- Usually recorded in
- Building and electrical permits and plans, which authorize defined work.
- What it doesn’t tell you
- Whether the work finished, or how much power actually flows. A rating is not the load.
Read more: power answers
3Backup generators
On-site generators, often diesel, run during grid outages and for routine testing.
- Number you’ll see
- How many generators and their rating, in kilowatts (kW) or megawatts (MW).
- Usually recorded in
- State or local air permits, which authorize defined emissions and can limit running hours.
- What it doesn’t tell you
- What the data center draws from the grid. A generation rating says what equipment could produce, not what the site uses.
DataCenterData has not yet checked air permits.
4Data halls and servers
Rooms of servers, storage and network equipment do the computing. They turn most of the electricity they use into heat.
The racks stand in rows, with a cold aisle on the side where air enters and a hot aisle on the side where the heated air leaves.
Source: U.S. Department of Energy guidance on data center design.
- Number you’ll see
- Critical IT load: the power planned for, or available to, the computing equipment, in MW. Announcements may give a campus total instead.
- Usually recorded in
- Company announcements and planning or zoning applications.
- What it doesn’t tell you
- Measured use. An announcement proves the company made the statement. A campus can contain several buildings built in phases, so one figure is not automatically one operating facility.
Power usage effectiveness (PUE) compares total facility energy with IT-equipment energy. It does not reveal a site’s total electricity use by itself.
Read more: every total and what it counts
5Cooling inside the building
Fans, coils and pumps move heat away from the equipment: by air, by liquid piped to the chips (direct-to-chip) or by immersing equipment in fluid.
In an air-cooled room, the design aims to keep the cooling air from mixing with the hot air the equipment gives off. Some designs replace the usual finned heat sink on a chip with a cold plate, which has liquid flowing through channels to remove the heat.
Source: U.S. Department of Energy guidance on data center design.
- Number you’ll see
- Usually none. The design is described in words such as “air cooled”, “liquid cooled” or “closed loop”.
- Usually recorded in
- Company statements, and sometimes planning documents.
- What it doesn’t tell you
- Water use. “Closed loop” usually describes recirculation inside part of the system. It does not, by itself, prove zero withdrawal or zero consumption. The heat still has to leave the site (part 6).
Read more: cooling and water record set
6Heat out: cooling towerdry cooler
A cooling tower carries heat away by evaporating water. The evaporated water is consumed. Make-up water replaces it, and some water is drained off (blowdown) to limit mineral build-up; that drained water becomes discharge.
A dry cooler blows air across coils that carry the warm loop. Running dry, it evaporates no water. Electricity demand depends on the weather, operating temperatures and the rest of the cooling system. Some designs spray water on the hottest days, and that water evaporates.
Sites can also use chillers, or a combination of these. An airside economizer uses outdoor air to cool the inside of the building when the weather allows, and a chiller can supplement it when that is not enough.
Source for the outdoor-air method: Lawrence Berkeley National Laboratory, data center energy report, 2024.
- Number you’ll see
- Usually a design described in words. Water figures appear with the water connection (part 7).
- Usually recorded in
- Company statements and site plans.
- What it doesn’t tell you
- How much water or electricity the site uses. Climate, utilization and cooling design all change the result.
Read more: cooling and water record set · water answers
7Water in and out
A water connection supplies the site, and a sewer or discharge connection takes water away. With a cooling tower, the cooling system takes in make-up water and sends blowdown to discharge.With dry coolers, cooling may need little make-up water, but the site can still withdraw water for other uses.
- Number you’ll see
- Water withdrawal, consumption or discharge, often as a permitted or contracted maximum, in gallons per day or millions of gallons per year.
- Usually recorded in
- Water-utility agreements, withdrawal permits, and wastewater or discharge permits.
- What it doesn’t tell you
- How much water is used. A permitted or contracted amount is a limit or a commitment, not a measurement. Withdrawal, consumption, discharge, potable water and reclaimed water are separate measures, and water used to generate the site’s electricity is a separate, off-site figure.
Read more: cooling and water record set · water answers
Power is a rate; energy adds up over time.
= MWh (876 GWh)
MW × hours = MWh. This is arithmetic for the number you enter, not an estimate for any facility. A request, capacity or rating is not an average draw.
Power is a rate; energy adds up over time. 100 MW drawn on average for a full year (8,760 hours) is 876,000 MWh. A request, capacity or rating is not an average draw.
One site can produce several different counts
A project is a development effort. A campus is a site that may contain several buildings. A building is one physical structure. An operating facility is a building or bounded site supported as operating. A provider presence can be only a tenant suite inside someone else’s facility.
Those units can overlap. Adding them together double-counts the same physical place. That is why DataCenterData keeps its record units and counting rules visible.
Developer, owner, operator and tenant are different jobs
A developer proposes or builds the project. An owner holds the land or buildings. An operator runs the data-center facility. A tenant occupies space or uses capacity inside it. One company can hold more than one of those roles; a cited record can also name none of them.
When developer, operator or tenant is blank here, the wording is: not named in the cited records. When owner is blank, the wording is: Owner of record not established. Neither phrasing finds that nobody occupies the role. Owner of record not established means the cited documents do not establish the owning legal entity, even if a form names an individual contact or property-owner field.
Power and energy are not the same number
A megawatt (MW) is a rate of power at a moment. A megawatt-hour (MWh) is energy used over time. A utility-service request, contracted capacity, anticipated site demand, critical IT load, backup-generator rating and measured grid load are different measurements. They should not be silently substituted or added.
Utility service or contracted capacity. What the site asked a utility for, or what a contract or service limit allows. It covers the whole connection to the grid, including power for cooling and other support systems. It is not how much electricity the site uses.
Critical IT load. The power planned for, or available to, the computing equipment. It leaves out cooling and other support systems, so it is a different number from the site’s utility capacity. An announced figure is a plan, not a measurement.
Backup-generator rating. What the generators could produce. It is not what the site draws from the grid.
Measured grid load. What a meter recorded the site drawing. This is the only one of these that measures use, and it is rarely published.
Power reaches the computing equipment through substations, transformers, switchgear and power-conditioning equipment. Some electricity also runs cooling and other support systems. Power usage effectiveness, or PUE, compares total facility energy with IT-equipment energy; it does not reveal a site’s total electricity use by itself. For national context, see the U.S. Department of Energy data-center resource hub.
Where the power comes from
A data center normally buys electricity through a utility or competitive supplier. The physical grid may serve many customers even when a company signs a contract associated with a particular generator. On-site backup generators, a proposed power plant, a utility service limit and the servers’ critical IT load are separate figures. A generation rating says what equipment could produce; it does not say what the data center is drawing from the grid.
Cooling moves heat; the water result depends on the design
Computers turn most of the electricity they use into heat. Air cooling, direct-to-chip liquid cooling and immersion cooling move that heat in different ways. Heat can ultimately be rejected with dry coolers, chillers, cooling towers or a combination.
“Closed loop” usually describes recirculation inside part of the system. It does not, by itself, prove zero withdrawal or zero consumption. Withdrawal, consumption, discharge, make-up water, potable water, reclaimed water and avoided potable use are separate measures. Climate, grid mix, server efficiency, utilization and cooling design all affect the result; Berkeley Lab’s water-use review explains why there is no single universal number.
Open the cooling and water evidence →
A project moves through stages
Announced means someone described a plan. Proposed means review or approval is still pending. Approved means a named approval exists, not that construction began. Construction requires evidence of physical work. Operating requires evidence that the facility or a defined phase entered service. Withdrawn, expired and closed projects stay in the history instead of disappearing.
Who approves what, and what the paper proves
Local planning and zoning records can establish land-use permission. Building and environmental permits authorize defined work or emissions. Utility and commission filings can establish requests, contracts or cost-allocation rules. Tax and development agreements can establish legal commitments. None of those documents alone proves that construction finished, a building opened, a promised job exists or a projected amount of power or water is being used.
Ask for the project or case number, adopted approval, issued permit, utility docket, parcel ID, agreement, inspection or certificate of occupancy, plus the date and the exact phase it covers.
Jobs, taxes and incentives need denominators
Peak construction workers, construction job-years, permanent employees and contractors are different quantities. Announced investment is not completed investment. A tax exemption, abatement, payment in lieu of taxes, special charge and gross tax receipt affect different ledgers. A useful local-outcome claim states the place, period, payer, recipient and whether the figure is authorized, promised, paid or observed.
Read the jobs brief → · Read the incentives brief → · Read the ratepayer brief →
How to read a DataCenterData claim
- Read the exact statement and who made it.
- Check the unit, place, scope and date.
- Open the cited source and its page, clause or record locator.
- Read what the source supports—and what remains unknown.
- Check the verdict date and visible correction history.
A missing operating record does not prove that a site is closed. A permit does not prove use. A company announcement proves that the company made the statement, not that the future outcome has occurred.
Browse evidence and sourced answers → · See corrections and lifecycle changes →