Utility capital plans for capacity upgrades

A public hosting capacity map tells you what’s true now. A rate case docket, filed months or years earlier, tells you what a utility already knows is coming.

NYSEG and RG&E made this explicit in a joint petition to New York regulators for what they called Urgent Upgrade Projects. The filing flags that 35% of NYSEG substations and 42% of RG&E substations have at least one circuit or transformer so capacity-constrained that only 1 MVA of headroom remains. It names a set of substations that the utilities believe need accelerated capital treatment, filed with the state.

How a constraint gets funded

The process starts with a load forecast showing that a circuit’s expected peak is going to cross its rated limit within the planning horizon. San Diego Gas & Electric’s filings illustrate the mechanics in one of their filings. As an example, a circuit rated at 12 MW at a weather-normalized peak of 10 MW today, with 2.5 MW of forecast growth over the next several years, crosses the 12 MW limit even though no new customer or project caused it on its own. By the time a specific new large load shows up inquiring about that circuit, the utility may already be planning to upgrade it.

Once a circuit trips that trigger, utilities search for other alternatives before building something new. Rate case testimony from Southern California Edison describes a sequencing logic:

• Check for cheaper operational or configuration fixes first.
• Then evaluate genuine infrastructure alternatives for technical feasibility.
• Only then select whichever solution is most cost-effective among the options that solve the constraint.

Some constrained circuits get a relatively modest fix, such as reconfiguring how load is split across existing equipment, while others end up needing the kind of multi-year, multi-million-dollar substation project that shows up as its own line item in a rate case.

General system-wide capacity investment typically gets recovered through rate base, spread across the whole customer population the same way most infrastructure costs are. But a project driven specifically by one large customer’s request is different in several regions. Silicon Valley Power, for example, directly assigns the full cost of a dedicated substation to the customer whose load required it. AEP Ohio’s line-extension policy assigns a defined share, 40% in the case of non-residential customers, of certain extension costs directly to the customer benefiting from them.

The same nominal upgrade can mean “the utility is already planning to construct this on everyone’s dime” or “you would be paying a meaningful share of this yourself,” and the difference is only visible from reading how the project is characterized in the filing that first proposed it.