​Regulators across North America are wrestling with a new question. Can a utility be legally required to deliver heat the way it delivers gas or electricity? A thermal energy network forces that question into the open.

These systems move thermal energy through shared water loops rather than through combustion at each building. That shift changes the regulatory picture, and it lands squarely on the desks of engineers, contractors, and utility planners. If you design or install ground heat exchangers, the answer shapes your next decade of work.

Thermal Energy Network: What "Obligation to Serve" Means When the Commodity Is Heat

Obligation to serve is a long-standing utility principle. A regulated utility must provide service to any customer inside its territory who requests it and meets the terms of the tariff. The concept was built around gas pipes and electric wires. It assumed a commodity that could be metered at a single point and delivered on demand.

Thermal service breaks several of those assumptions. Heat exchange is bidirectional. A building rejects heat in summer and absorbs it in winter. The ground heat exchanger (GHX) is a shared asset, so one customer's behavior affects the next. Regulators must therefore define what "service" actually means before they can require anyone to provide it.

Several practical definitions are now in play across state proceedings:

• Service as GHX access, where the utility owns the buried infrastructure and guarantees a temperature range at the property line
• As delivered comfort, where the utility owns equipment inside the building and guarantees indoor conditions
• Service as a capacity right, where the customer buys a reserved thermal load rather than a measured quantity of heat

Each definition assigns risk differently. Each also creates a different scope of work for the installers and designers who build the system.

How State Rules Are Framing Thermal Energy Network Territory

New York, Massachusetts, Colorado, Maryland, and Vermont have all moved on thermal network legislation or dockets. The details differ, but a few patterns repeat. Most statutes allow gas utilities to own and operate thermal networks. Many require pilot projects before broad authorization. Several direct commissions to study whether the traditional duty to serve should extend to thermal service at all.

The territory question is the hardest part. Gas and electric franchises follow geography. Thermal networks follow load diversity instead. A cluster of mixed-use buildings makes a strong network because the loads offset each other. A subdivision of identical homes with identical schedules does not. Regulators are learning that thermal service territory may look more like a mosaic than a map.

This is why district systems and TENs are usually authorized as defined project areas rather than blanket obligations. A commission can require a utility to serve everyone in a designated network footprint. Requiring it everywhere would ignore the physics of load sharing.

Where Ownership Boundaries Meet Engineering Reality

Regulatory language draws a line between utility-owned and customer-owned equipment. Field crews then have to build to that line. The boundary usually sits at the ground heat exchanger, the heat pump, or somewhere in between. Wherever it sits, it determines who is responsible for performance, maintenance, and long-term thermal balance.

Third-party and utility ownership of the buried piping has been discussed in the industry for years. The reasoning behind it is laid out well in this look at the value of the ground loop heat exchanger for third-party owners. The ground heat exchanger is the longest-lived component in the system. It behaves much more like utility infrastructure than like an appliance.

That distinction matters for obligation to serve. A regulator can reasonably require a utility to maintain a 50-year buried asset. Requiring it to guarantee indoor comfort in a poorly commissioned building is a different matter. Clear ownership boundaries protect everyone, including the contractor who installed the GHX correctly.

What Regulated Service Means for Design, Commissioning, and Records

Once a GHX becomes regulated infrastructure, documentation stops being optional. Utilities answer to commissions, and commissions ask for evidence. Expect closer scrutiny of design assumptions, fusion records, purge and flush verification, and thermal conductivity testing.

Workforce credentials come under the same lens. Many state programs already tie thermal network work to certified installers and designers. Requirements vary widely, so it helps to review current licensing and CEU requirements by state before bidding regulated work. Utilities increasingly ask for proof of certification during procurement, not after.

Three habits will serve you well as these rules mature:

• Document GHX installation to a standard you would defend in a rate case
• Design for decades of thermal balance, not just for peak day capacity
• Train crews against published standards so your records match the utility's expectations

IGSHPA standards and training were written with exactly this level of rigor in mind, well before thermal networks entered the regulatory conversation.

Position Yourself Before the Rules Are Final

You do not have to wait for a commission ruling to get ready. The utilities pursuing thermal networks are already looking for partners who can prove their work. Your certifications, your documentation, and your GHX design practices are what make you that partner. IGSHPA training and certification gives your team the credentials utilities are starting to require, and membership connects you with the people writing and interpreting these rules right now.

Join us at the IGSHPA Annual Conference to hear directly from the utilities, regulators, and designers shaping thermal network policy in your state. Send us a message for any specific questions or concerns.