Interconnection, ATC, and Offtake: The Power Vocabulary Every Site Selector Needs in 2026

Available transfer capacity, interconnection queue position, and offtake capacity are the three terms that now decide whether a data center or renewable energy site actually works, before land price, tax incentives, or fiber ever enter the conversation. If you can't quickly answer "how much power can this substation actually deliver, and how long until it's available," you don't yet have enough information to evaluate a site. This guide defines the terms that matter, in plain language, with real numbers behind each one.

Power, not land, is the resource that is actually scarce in 2026. Understanding these eight terms is the fastest way to read a due diligence report, a utility interconnection study, or a power availability analysis without getting lost in acronyms.

What is available transfer capacity (ATC)?

Available transfer capacity, or ATC, is the amount of additional power a piece of grid infrastructure, usually a substation or transmission line, can carry without exceeding its safe operating limits. It is the single number that tells you whether a site has real headroom or is already maxed out. LandGate tracks ATC across more than 65,000 mapped substations nationwide, because a parcel next to a substation with zero ATC is not a powered site, no matter how good the land looks on paper.

What does "interconnection queue" mean, and why is it taking years?

The interconnection queue is the formal line of projects, both generation and large loads, waiting for a grid operator or utility to study and approve their connection to the grid. In parts of PJM, that wait now exceeds six years. Every project ahead of yours in the queue can also change the study results for your own request, which is why queue position is treated as a serious risk factor, not a scheduling inconvenience, by developers evaluating interconnection risk in 2026.

What is offtake capacity, and how is it different from injection capacity?

Offtake capacity is how much power a substation can deliver to a load, such as a data center or factory, without upgrades. Injection capacity is the mirror image: how much power a generator, such as a solar or wind farm, can push onto the grid at that same point. A data center developer cares most about offtake. A renewable developer cares most about injection. The two numbers can be very different at the same substation, which is exactly why both need to be checked independently rather than assumed. LandGate's data center due diligence reports break this out explicitly for every site.

What does "behind the meter" actually mean?

Behind the meter describes power that is generated and consumed on the same side of the utility meter, without traveling through the public grid at all. A solar array or gas turbine built specifically to power an adjacent data center, rather than to sell electricity to a utility, is a behind-the-meter asset. LandGate's research found that behind-the-meter generation now represents more than 25 percent of new U.S. data center capacity, precisely because it can bypass the interconnection queue described above.

What is a "readiness deposit," and why does it matter?

A readiness deposit is a non-refundable payment a developer puts down, often early in the interconnection process, to demonstrate the project is real and to cover the utility's or grid operator's early study costs. These deposits can reach $4,000 per megawatt for large campuses, meaning a 250 MW data center can face roughly $1 million in fees before construction ever begins. It is one of the clearest signals that power availability, not real estate, is the gating factor on a modern site.

What is "powered land"?

Powered land is a shorthand term for a parcel that already has, or can quickly obtain, enough grid capacity to support its intended use, whether that's a data center campus or a utility-scale solar farm. A parcel can be zoned correctly, permitted, and beautifully located, and still not be powered land if the nearest substation has no offtake or injection capacity left. This is the single most common mismatch in early-stage site selection.

What is curtailment?

Curtailment happens when a grid operator instructs a generator to reduce or stop output, usually because the grid can't absorb any more power at that moment. It matters to renewable developers because a project can have plenty of injection capacity on paper and still lose revenue to curtailment during high-output periods. It's a second layer of risk beyond the interconnection queue itself.

What is co-location, in the power sense?

Co-location refers to placing a load, like a data center, and a generation source, like a solar or battery storage facility, on the same site or immediately adjacent to one another, often specifically to use behind-the-meter power and avoid grid bottlenecks. It is becoming the defining strategy for large power users in constrained markets, and it's the subject of Part 3 of this series.

Frequently asked questions

What is available transfer capacity (ATC) in simple terms?

ATC is the amount of extra power a substation or transmission line can carry safely, on top of what it's already delivering. It's the first number to check when evaluating whether a site actually has usable power.

How long is the interconnection queue in 2026?

It varies significantly by grid operator and location, but wait times in parts of PJM now exceed six years, according to LandGate's research into the data center power challenges.

What's the difference between offtake capacity and injection capacity?

Offtake capacity measures how much power a substation can deliver to a load, such as a data center. Injection capacity measures how much power a generator can push onto the grid at that same location. They are checked separately and can differ substantially.

What does behind-the-meter power mean for a data center?

It means the data center's power is generated on site or immediately adjacent, without relying on the public grid connection, which can let a project sidestep interconnection queue delays entirely.

Why do utilities charge a readiness deposit?

It covers the utility's or grid operator's cost of studying a proposed connection and signals that the developer is serious enough to move forward, since the deposit is typically non-refundable.

What is powered land?

Land that already has, or can quickly secure, enough grid capacity for its intended use. Zoning and permitting alone don't make land powered; the nearby grid infrastructure has to have real available capacity.

Why does curtailment matter for solar and wind developers?

Even a project with strong injection capacity on paper can be told to reduce output when the grid is oversupplied, which directly affects expected revenue and needs to be modeled into a project's economics.

What is co-location in data center and renewable siting?

Placing generation, like solar, wind, or battery storage, on or next to the site of a large power user, like a data center, specifically to use behind-the-meter power and reduce dependence on grid interconnection.

Where ATC, Interconnection, and Offtake data leaves you

None of these terms (ATC, interconnection, offtake) are complicated once you have real numbers attached to them. The hard part is getting current, site-specific figures instead of averages, since interconnection queues, deposit costs, and available capacity all shift by grid operator, utility territory, and even by individual substation. That's the gap LandGate's site analysis platform is built to close.

Next in this series: Part 2 looks at why power, not land, has become the real bottleneck in data center site selection, with the numbers behind a six-year queue and a $1 million entry fee.

Ready to check a real site?

See what powered land actually looks like. Run a free offtake capacity check on a parcel you're evaluating, or talk to LandGate's team about a full due diligence report before you make an offer.