This guide sets out how to plan around a delayed interconnection: how to phase on-site plant, how to decide between bridge and permanent generation, and how to keep the eventual grid tie simple.
Get the real interconnection picture first
Before designing any plant, pin down what the utility can actually offer and when. Ask for the capacity available at each date, the upgrades it depends on and the risks to that schedule. A connection that offers part of the load early and the rest later changes the on-site plant design completely compared with one that offers nothing until a single date.
Write the answer as a load-versus-time chart with the utility’s committed capacity on one line and the campus demand on another. The gap between the two lines is the on-site generation requirement, year by year.
Bridge power or permanent plant
Bridge power fills the gap until the grid arrives and then leaves or becomes backup. Permanent on-site plant runs for the life of the campus, with the grid as a supplement or backup. The choice depends on gas availability, emissions permits, how long the gap is expected to last and the owner’s appetite to run a power plant.
If the gap is short and uncertain, relocatable units may suit. If the gap is long, or the grid may never offer the full load at an acceptable reliability, a permanent plant designed for the campus is usually the better investment.
Sizing for compute load
AI and high-density compute loads change quickly and can swing sharply as training jobs start and stop. On-site plant has to follow those swings without tripping. That points to multiple generating units with spinning reserve, fast controls and often battery energy storage to smooth steps, rather than a few large units running near their limit.
Redundancy must also be designed in. With no grid behind the plant, N+1 or better at the generation level and in the electrical distribution is the minimum for a campus that has promised its tenants high availability.
Gas supply and fuel backup
Most permanent on-site plants for large campuses run on natural gas. A pipeline lateral, metering station and gas conditioning take time and permits of their own, so they belong on the same critical path as the generators. Ask the gas utility for firm capacity and pressure, and check how the supply behaves in cold weather when other users compete for gas.
Plan a fuel backup for when gas is interrupted. Dual-fuel capability, on-site liquid fuel storage or a separate standby system protect the campus if the pipeline is down.
Modular gas turbine blocks
Building the plant in modular blocks lets capacity follow the campus build-out. Each block can be ordered, installed and commissioned as a data hall comes online. The New USP&E FX-45 45MW Modular Gas Turbine for the Hyperscale Data Center sector in the USA is designed for this kind of phased approach, with production slots from 2028 to 2030.
See how modular gas power blocks support a campus build for a step-by-step view of matching blocks to halls.
Designing for the future grid tie
Even if the grid is years away, design the campus substation and protection so the utility can connect later without a rebuild. Reserve space for the utility bays, plan the switching arrangement so the plant can run islanded or in parallel with the grid, and agree early what the utility will require for parallel operation.
Ask the utility for its interconnection requirements in writing during design. Protection, metering, telemetry and power quality rules are easier to build in from the start than to retrofit.
Permits and community
On-site generation needs air permits, noise studies and sometimes water permits for cooling or emissions control. These can take as long as the plant itself, so start them as soon as the plant concept is fixed. Being open with neighbours about plant size, stacks and noise helps avoid objections later.
Keep the permit application consistent with the phased design. Applying for the final campus size, with a clear phasing plan, avoids re-permitting each time a block is added.
Contracts and responsibility
When the plant is the only source of power, the contract structure matters. Owners can build and operate the plant themselves, hire an EPC contractor and a separate operator, or contract one party to design, build and operate. The more the campus depends on the plant, the more value there is in a single party being accountable for both delivery and availability.
Whatever structure you pick, write availability, response times and performance tests into the contract, and make sure the EPC handover feeds directly into the O&M plan.
About the authors
Utility queue delays are now a standing agenda item when our data center power team meets developers. Insight from the USP&E data center power team, who plan and deliver on-site generation for hyperscale and colocation campuses. USP&E builds and maintains power plants under its own name, not as a reseller, backed by 25,000 MW contracted since 2002, 150+ power projects in 45+ countries and 24+ years in the field. Read about our work on data centre power.
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Questions about grid delays
Can a data center run without a grid connection?
Yes, with on-site generation designed for full load, redundancy, fast response to load changes and a backup fuel plan. Many campuses now plan this way while waiting for the utility.
Is bridge power or a permanent plant better?
Bridge power suits short, uncertain gaps. A permanent plant suits long gaps or campuses where the grid may never offer the full load reliably.
What fuel do on-site data center plants use?
Usually natural gas, with dual-fuel capability or a separate standby system for when gas supply is interrupted.
How do I avoid a rebuild when the grid arrives?
Reserve space for utility bays, design protection and switching for parallel operation, and obtain the utility’s interconnection requirements in writing during design.
When are production slots for the modular turbine offered?
Slots for the New USP&E FX-45 45MW Modular Gas Turbine for the Hyperscale Data Center sector in the USA are offered from 2028 to 2030.
Facing a late interconnection date?
Share the campus load ramp and the utility’s offer, and our engineers will map the on-site generation needed year by year.
For a first conversation, use the data center enquiry page, ring +27 10 822 2324 or send the details to info@uspeglobal.com. Turbines that can bridge or carry campus load are shown in our natural gas turbine inventory.