A plain-language field guide to the words that show up in data-center debates — from the equipment on the campus to the deals that get it approved. Bookmark it and come back.
Hyperscale
The largest class of data center: a campus of server buildings, often on hundreds of acres, operated by a cloud or AI company at massive scale. A single hyperscale site can draw hundreds of megawatts. See how they work.
Colocation (“Colo”)
A data center where a developer builds the building and infrastructure, then leases space, power, and cooling to multiple tenants who install their own servers — as opposed to a single company owning the whole campus.
Megawatt (MW)
The standard unit for a data center’s power demand. One megawatt is a million watts; a large campus may request several hundred. Watching the megawatts is the fastest way to gauge a project’s impact on the grid. See where the power goes.
Interconnection
The process of connecting a large new electricity user (or generator) to the grid. A data center’s interconnection request tells the utility and grid operator how much power it needs and when — and the queue for it is often public.
Substation
Equipment that steps high-voltage transmission power down to a level a facility can use. Large data centers frequently require a new or expanded substation, a telling sign of the load a project will add.
Load
The amount of electricity a facility draws at a given moment. “New load” from data centers is what forces utilities to plan new generation, transmission, or — in some cases — to keep older plants running.
PUE (Power Usage Effectiveness)
A ratio of a data center’s total energy use to the energy used by its computing equipment alone. A PUE near 1.0 means little power is “wasted” on cooling and overhead; higher numbers mean more.
WUE (Water Usage Effectiveness)
A measure of how much water a data center uses per unit of computing energy. It captures the water side of the trade-off that PUE misses — a site can post a low PUE precisely because it uses water instead of electricity to cool.
Evaporative Cooling
A common cooling method that uses the evaporation of water to shed heat from servers. It is energy-efficient but water-intensive, which is why local water supply is a central data-center question. See where the water goes.
PILOT (Payment in Lieu of Taxes)
An agreement in which a project pays a negotiated, usually reduced amount instead of standard property taxes for a set number of years. PILOTs are a common data-center incentive and a key thing to scrutinize before a vote.
Tax Abatement
A reduction or exemption of taxes — property, sales, or both — granted to attract a project. Data-center abatements can run for decades, so the long-run fiscal math matters as much as the headline investment figure.
Rezoning
Changing the zoning designation of a parcel to permit a use it didn’t previously allow — for example, from agricultural or residential to industrial. A rezoning hearing is often the public’s clearest chance to weigh in on a data center.
Special-Use Permit (Conditional Use)
Permission to build a use that isn’t automatically allowed in a zone but may be approved with conditions. Data centers frequently need one, and the conditions attached are where accountability can be built in.
By-Right Development
A project that already complies with existing zoning and needs no rezoning or special permit — meaning it can proceed with little or no public hearing. When a data center is proposed “by right,” residents have far fewer formal chances to be heard.
Power Purchase Agreement (PPA)
A long-term contract to buy electricity, often used by operators to claim clean-energy supply. Reading the fine print matters: a PPA on paper doesn’t always mean the local grid serving the campus is any cleaner.
Ratepayer
Anyone who pays an electricity or water bill in the utility’s service area. A recurring accountability question is whether the cost of new infrastructure for a data center is borne by the operator or spread onto ordinary ratepayers.
Behind the Meter
Power generated on-site and used directly by a facility without passing through the public grid’s meter. Some operators propose behind-the-meter generation to speed up projects — which raises its own oversight questions.
Water Rights
The legal entitlement to draw water from a given source. In water-stressed regions, a data center’s water rights and permitted withdrawals are among the most consequential public records to request.
Now put it to use
You know the vocabulary — go find out what’s being built in your own state.