Every word you need, in plain English. Ten of them cover almost everything a homeowner runs into. The other 36 are the vocabulary the industry uses, for when you need it.
Start here — the ten words that matter
If you have just heard that a data center might be built near you, this is the whole vocabulary.
Data center
A building full of computers. The big new ones are for AI, and they use as much electricity as a small town.
Megawatt (MW)
A unit of electrical power. One megawatt runs roughly 800 average US homes, so a 300 MW data center uses about what 240,000 homes use.
The grid
The network of wires that carries electricity from where it is made to your house.
Interconnection queue
The waiting list to plug something new into the grid — a solar farm, a battery, or a data center. Joining the list is not permission to build.
Interconnection request
An application to join that waiting list. It is a request, not an approval, and most are never built.
Withdrawn
The company gave up on that project. This is the most common ending, nationally — usually a developer testing a site and moving on.
Large load
Any single new customer that needs a lot of power at once. A data center is the kind everyone is arguing about.
Grid operator
The organization that runs the waiting list and keeps the lights on for a whole region — PJM in the mid-Atlantic, ERCOT in Texas, and so on.
Tariff
The rulebook that says what a customer pays and on what terms. Several states are writing new ones aimed specifically at data centers.
Moratorium
A temporary ban on new data centers, or on connecting them, while a government decides what its rules should be.
The industry vocabulary
Written for people making siting decisions, not for a tariff. Where a term has a precise regulatory meaning that differs from ordinary use, the entry says so. Free to quote with attribution.
Time and delivery
Term
What it means
Speed to power
How long it takes from deciding on a site to having usable grid power there. It is the phrase the data center industry uses in place of 'interconnection timeline', because the buyer is purchasing time, not a queue position. Also written time to power.
Time to power
The same thing as speed to power: elapsed time from site decision to energization. Typically quoted in years, and in most US markets it now runs longer than the time to build the facility itself.
Energization
The moment a site is actually connected and can draw power. An energization date is the number that matters commercially — a signed interconnection agreement is not power.
First power
The date the first block of capacity at a site becomes usable, as distinct from the date the full build is energized. Large campuses are usually phased.
Bridge power
Temporary on-site generation used to run a facility before the grid connection is ready. Also bridge generation or bridge-to-grid.
Queue and process
Term
What it means
Interconnection queue
The ordered list of requests to connect to a transmission system. Each request is studied in turn, and the queue is public for generation in most of the US.
Large load interconnection request
A request to connect a large new electricity consumer — typically a data center, above a threshold such as 50 MW — rather than a generator. ERCOT's formal term. Unlike generation, these carry no federal transparency requirement, so most are never published.
Cluster study
A study of a group of interconnection requests together rather than one at a time. Introduced by FERC Order 2023 to clear queue backlogs. Requests can only join during a cluster window.
Cluster window
The fixed period when a transmission provider accepts new interconnection requests. Usually annual. Miss it and the next opportunity is a year away — which is why the window date is worth diarising.
Restudy
Re-running an interconnection study because something ahead of you in the queue changed, usually a withdrawal. A restudy can move both your timeline and your network upgrade cost, and it is the single most disliked word in the process.
First-ready, first-served
The replacement for first-come, first-served: position depends on readiness — site control, deposits, and completeness — not on the date you filed.
Site control
Documented legal right to use the land, usually a deed, lease or option. Now a prerequisite for entering most queues.
Readiness deposit
A payment, often per megawatt and often non-refundable, required to enter or stay in a queue. It exists to deter speculative requests.
Withdrawal
A request leaving the queue before it is built. Roughly three quarters of the capacity that entered US queues between 2000 and 2020 was withdrawn, which is why queue totals are not a pipeline forecast.
Capacity
Term
What it means
Available transfer capacity
Abbreviated ATC. How much additional power a substation or line can carry without exceeding safe operating limits. The technical version of 'is there room here'.
Offtake capacity
How much power a substation can deliver to a load — a data center or factory — without upgrades. The load-side counterpart to injection capacity, which is what a generator can push onto the grid at the same point.
Headroom
Informal term for spare capacity on a piece of grid infrastructure. Feeder headroom refers to a distribution feeder specifically.
Deliverable capacity
Power that can actually be delivered to a site, as opposed to theoretical capacity implied by nameplate ratings. The gap between the two is where projects fail.
Hosting capacity
A utility-published map of how much new generation a distribution system can accept. Note it is generation-oriented and distribution-level, so it does not answer a large load question directly.
Cost and rights
Term
What it means
Network upgrades
Transmission or substation work triggered by a new connection. The interconnection customer usually pays, the cost is only known after study, and it is the most common reason a project is abandoned.
Capacity interconnection rights
Abbreviated CIRs. In PJM, the right to sell capacity associated with an interconnection. They attach to a position and can be transferred, which is why a retiring plant's rights have value to a new load.
Will-serve letter
A utility letter confirming it will provide service to a site. Frequently required for financing or permitting, and often the first hard commitment in the whole process.
Contribution in aid of construction
Abbreviated CIAC. An upfront customer payment toward infrastructure the utility builds. Increasingly used to shield existing ratepayers from large load costs.
Policy and tariffs
Term
What it means
Large load tariff
A rate schedule created specifically for very large customers, typically with minimum terms, minimum demand charges and exit fees. Twenty-four states had approved at least one by August 2026.
Data center moratorium
A local or state pause on new data center approvals, usually time-limited. They can be enacted quickly and can strand a site that was viable when it was optioned.
Take-or-pay
A tariff structure obliging the customer to pay for a contracted quantity of power whether or not it is used. Common in large load tariffs, and a major term in any negotiation.
How power is supplied
Term
What it means
Behind the meter
Generation on the customer's side of the utility meter, serving the load directly. Contrasted with taking network load service from the grid.
Co-location
Siting a large load directly at a generator. The subject of FERC's PJM proceedings, because it raises who pays for the grid the load still relies on.
Bring your own power
Abbreviated BYOP. A developer supplying its own generation to shorten time to power. In PJM and ISO-NE policy documents the same idea appears as bring your own new generation.
Flexible load
A load that can reduce or shift consumption on request. Flexibility is increasingly the price of a faster connection, because a curtailable load needs less firm capacity.
Land and buildings
Term
What it means
Powered land
A parcel that already has, or can quickly obtain, enough grid capacity for its intended use. The scarce asset in data center real estate, and priced accordingly.
Powered shell
A completed building with power and cooling infrastructure but no IT fit-out. Faster than greenfield, and a distinct product from powered land.
Shovel-ready
A site with permits, zoning and utilities resolved. Note it does not mean interconnection-ready — a site can be shovel-ready and still be years from power.
Risk and noise
Term
What it means
Phantom load
Interconnection requests that will never be built, inflating queue totals. Estimates suggest there are five to ten times more requests than data centers actually delivered.
Speculative queue position
A request filed to hold a place rather than to build. The reason readiness deposits and site control requirements exist.
Zombie project
A queue entry that is neither progressing nor withdrawn, occupying a position and forcing restudies for everyone behind it.
See these numbers for a real county
Every term above is something we publish for 1,607 US counties — what is queued, how long
the wait runs, what policy applies, and what closes next.