Grid capacity for data centers, screened site by site

Data center developers and other large loads keep asking the same question: where on the grid can we connect, and how much? Our ISO client had three candidate points of interconnection and needed a credible, engineering-based answer for each one before committing to siting and commercial decisions. A simple headroom estimate would not hold up. The ISO needed to know what would limit each site first, and how projects already in the queue could change the picture. The project was layered with complexity.

Why it Matters for Data Centers
Large-load siting decisions move fast, and the grid is often the constraint. This screening turned an open question into a site-by-site answer: how much load each point can host today, what breaks first, and how the queue could change it. That gives developers and asset owners a basis to prioritize sites, scope upgrades, and set realistic timelines before entering the formal interconnection process.

A credible hosting-capacity number needs more than a headroom estimate. Our screening traced how new load flows across the network, where it first runs into a limit, and how the interconnection queue changes the answer.
 

1. System model. PSSE on LTO PBCS base cases, system intact (N-0), high summer peak dispatch.
2. DFAX screening. Distribution-factor analysis traced how each load injection spreads across the network.
3. Limit identification. Overload tracking found the first element that caps each site's capacity.
4. Independent per-POI evaluation. Each point assessed on its own, covering local and tie-line effects.
5. Queue sensitivity. Capacity compared with nearby queued projects to isolate impact.

For each point of interconnection, the ISO received:
 

• A defensible hosting-capacity basis grounded in planning cases
• The first limiting element that would cap new load at that site
• A clear view of queue sensitivity
• Findings aligned to its siting and commercial timelines

The evaluation indicated that the transmission system, including three substations, could reliably accommodate significant additional load at the three proposed Points of Interconnection (POIs). The ISO was able to confidently move forward knowing that the maximum interconnection capacity available at each location was sufficient to support the increased load under existing and planned system conditions.