In early September, Pacific Gas and Electric reported results from a pilot that should interest every cooperative and municipal utility sitting on a constrained feeder.

The program is called Flex Connect. Customers agree to let the utility limit their capacity when the distribution system is constrained. In exchange, they connect in months rather than waiting years for firm service. Over the first two years, participating customers were able to draw their needed capacity in roughly ninety percent of hours. Most active and prospective sites are in the two to five megawatt range, with some data center and manufacturing prospects around ten megawatts. The customer links its own energy management system to the utility’s grid management system, which sends scheduled or real time capacity limits the load follows.

Two to five megawatts. That is not a hyperscale campus. That is a poultry processing expansion, a fleet charging depot, a grain handling facility, a school district bus yard, a small colocation site. That is the load showing up in cooperative and municipal territories right now.

The concept is simpler than the technology makes it sound

Strip away the software and flexible interconnection is an old utility idea in a new wrapper. You are selling a class of service that is not firm. Utilities have offered interruptible and curtailable service for decades. The difference is granularity. Instead of a seasonal load limit negotiated once a year, the limit moves with actual system conditions.

That difference is what makes the economics work for the customer. A fixed load limit forces the customer to size their operation around your worst hour. A dynamic limit lets them use the headroom that exists in the other ninety percent of hours.

What you actually need in place

Four things have to be true before a cooperative or municipal utility offers anything like this.

You have to know your real feeder headroom, hour by hour. Not the nameplate rating. Not last year’s peak. An accurate load flow model with current loading data, because the arrangement depends on knowing how much room exists at a given hour and defending that number to a customer who is contractually bound by it.

You have to be able to communicate with the site. This is where cooperatives that have built fiber have a real advantage. A utility with fiber to its substations and reclosers already owns the communications backbone that makes dynamic limits practical. Utilities without it need to solve communications first, usually through a mix of fiber, wireless, and existing SCADA.

Your protection has to still coordinate. A curtailable load is a variable load. Fault current does not change with load, but the operating condition your protection was set for may have been a static assumption. Verify coordination across the full range of loading you are now inviting.

Your rate and contract structure has to match. What is the customer’s obligation when they exceed the limit? What is yours if you curtail more than the contract contemplates? Who pays for the control equipment at the site? Those are cost of service and contract questions, and they should be settled before the first customer signs.

The strategic argument

Flexible interconnection is not a substitute for building capacity. It is a bridge. It gets revenue on your system while the substation upgrade proceeds, and it keeps an economic development prospect in your community instead of sending them to the next territory over.

For a cooperative or municipal utility, that second point is the whole game. You are frequently the reason a business stays in a county. A tool that lets you say yes earlier is worth understanding.

Where Finley fits

Finley performs the distribution load flow and voltage drop analysis that establishes real feeder headroom, sectionalizing and protective device coordination studies, substation capacity analysis, and rates and cost of service work. We also design IP networks and fiber, which means the communications layer and the power engineering can be handled by one team.

Want to know whether your system could support a flexible service offering? Start with a feeder headroom assessment. Call 800-225-9716.