PUC presses PSCo for transmission‑cost estimates, weighs capacity vs. asset‑health spending

At its deliberation meeting, the Colorado Public Utilities Commission directed Public Service Company of Colorado to provide estimates of transmission costs associated with planned distribution investments and debated whether the GMAC should prioritize capacity expansion projects over broader asset‑health and reliability spending.

Advisors told commissioners the DSP includes a large capacity program (proposed 413–478 million per year in capital for 2026–2028 in company workpapers) and a sizable asset health and reliability (AHR) program that rises from about $224 million in 2024 to $364 million in 2028. The utility’s grid needs assessment lists proposed projects — including new feeders, transformer banks and substations — but the company did not include transmission upgrade estimates for the substations or the cost to energize the new distribution infrastructure.

Advisors recommended the commission require the company to file, within 60 days of the final phase‑1 decision, its best estimates of transmission costs imposed by distribution investments in this DSP and how it proposes to recover such costs. Dan Greenberg told commissioners that UCA had emphasized the record lacked any estimate of upstream transmission cost and that the commission cannot fully assess the DSP’s total system cost without that information.

Commissioners also examined competing proposals to prioritize or delay capital projects. Staff and some intervenors proposed mechanisms (for example, a risk‑uncertainty framework or the Sweep/NRDC approach) that would give priority to feeders by the speed of load growth or otherwise raise the threshold that triggers a capacity upgrade, potentially reducing near‑term capital spending for less time‑sensitive projects. Advisors favored the Sweep/NRDC approach because it accounts for the rate of load growth rather than a fixed percent shift in trigger thresholds.

The record included contested views about targeted undergrounding. UCA urged large reductions in proposed AHR spending, including a 50% cut to targeted undergrounding on the grounds of overlap with wildfire mitigation programs and lack of cost‑benefit detail. PSCo responded that its “targeted undergrounding” differs from its wildfire mitigation undergrounding and that it coordinates planning to avoid double‑spending. Commissioners asked for more detailed mapping, miles by year and cost benefit analysis for undergrounding to be included in future filings.

Why it matters: without transmission‑upgrade estimates and clearer project‑level justifications, the PUC cannot judge total system cost, affordability, or whether nonwires alternatives or other planning tools could avoid or defer capital spending. Commissioners asked staff to return with options to constrain GMAC recovery while meeting urgent capacity needs.

Taper: advisors will request the company to file transmission‑related cost estimates and mapping; the PUC will consider those filings and return to unresolved questions — including how much AHR belongs in GMAC recovery — at a later deliberation.