Rocky Mountain Power included TerraPower's Natrium demonstration project in the utility's preferred portfolio for the 2025 integrated resource plan (IRP), but said the company is negotiating a unique commercial off‑take structure and is not treating the plant as a guaranteed reliability resource.

Dan McPhail, the presenter for Rocky Mountain Power at the Utah Public Service Commission technical conference, told parties the company "is currently negotiating an off day commitment with TerraPower so we would take the megawatts that they produce and pay them for the megawatts they produce" and described the arrangement as "an innovative commercial energy acquisition structure, you know, ensuring benefits for customers without risk." He added the company is "not planning to, to count on them for reliability or count them towards compliance and so forth. We can we can make do without it."

The utility said the project appears in the IRP as a distinct, identified resource with a commercial‑operation date that moved in the final filing from 2030 toward 2031–2032, and that the company is negotiating terms through 2025. Rocky Mountain Power said the Natrium entry is treated differently from the routine proxy resources used elsewhere in the IRP because it is a specific technology and an active commercial negotiation rather than a cost‑and‑performance proxy.

Salt Lake City Corporation's Christopher Thomas expressed concern about treating Natrium like a contracted resource before a contract is finalized, asking: "I'm concerned that the Natrium Resource is kind of being treated like a contracted resource when it hasn't been contracted yet." Rocky Mountain Power replied that the company included Natrium as a placeholder in the preferred portfolio because management expects the negotiated structure to be cost‑effective for customers, but that the IRP also contains variants that examine the portfolio without the nuclear entry.

Rocky Mountain Power said that, if Natrium did not proceed, the model replaces the nuclear entry with more wind, solar and battery resources and that doing so would change the value of wind and solar in the plan. The company described the Natrium modeling as a non‑cost‑based placeholder — not a conventional proxy resource — and said contract negotiations remain ongoing.