Los Alamos County utility staff told the Utilities Board on Oct. 1 that the Foxtail Flats solar-and-storage project is ready to move forward after a delayed land lease but that new market rules, uncertain tax credits and fluctuating local loads create a measurable risk of having to curtail daytime solar generation.

Ben Ulbrich, deputy utility manager for Power Supply, briefed the board on the county’s integrated resource plan (IRP) follow-up and focused on the county’s choices for handling an estimated 170 megawatts of photovoltaic (PV) capacity that will exceed the county’s direct daytime needs once Foxtail Flats is fully online.

Ulbrich said the project’s land lease was completed in August after an appeal period, which delayed developer mobilization and shifted commissioning dates. He said the developer now targets roughly Jan. 1, 2027, for an initial phase at about half capacity and full plant capacity within a few months after that; the project's earlier milestone was March 1, 2026.

Why it matters: With larger daytime solar output and limited local daytime demand, the county expects seasonal and hourly excess energy. If that power cannot be sold into markets or to local customers, Ulbrich said the county could face a “curtailment” cost in the neighborhood of $70 per megawatt-hour for generation it cannot accept — a figure that combines an energy cost estimate and the estimated foregone production tax credits.

Board members pressed staff on where the county could sell excess power and on reliability implications of shifting firm energy to Foxtail Flats. Ulbrich reviewed seven preferred responses, roughly prioritized by staff: 1) sell 10 MW of Laramie River Station (LRS) daytime output when solar is abundant, 2) arrange one- to five-year term sales to take excess PV off the county’s books, 3) increase day sales to Sandia National Laboratories/Kirtland Air Force Base beyond a notional 30 MW share, 4) enable automatic market dispatch for the county’s combustion gas turbine generator (CGTG) so it can bid into new markets, 5) sell into the extended day-ahead market (EDAM) or other third-party channels, 6) add more battery storage, and 7) curtail PV only as a last resort.

On markets and tariffs, Ulbrich said PNM will join CAISO’s EDAM (extended day-ahead market) around October 2027 and the county will participate as a transmission customer through PNM; the Southwest Power Pool (SPP) expansion of the Laramie River Station area is a separate regional change. Both moves mean the county will have to fit into new day-ahead and regional market scheduling paradigms, Ulbrich said, and that PNM’s approach will determine how the county interacts with EDAM in practice.

Ulbrich also described load forecasting uncertainty tied to Los Alamos National Laboratory (LANL) operations. He noted LANL’s linear accelerator and new computing facilities have repeatedly underperformed earlier load forecasts and that slower-than-expected electrification also reduces county daytime demand projections. Those variables make it harder to predict how much excess solar the county will have at different horizons.

Board member questions and staff direction: Board members asked for a simpler briefing on EDAM and how the new markets will affect county operations; Chair Gibson and staff agreed to schedule an educational briefing for the board. Ulbrich said staff is gathering indicative pricing offers for short-term purchases to cover the interval between the original Foxtail Flats start date and the developer’s revised schedule. He also said staff may bring a financial-gap analysis to the board later this year.

On storage economics, Ulbrich presented modeling that showed adding 20 MW/80 MWh of extra battery capacity could reduce curtailment risk but would not pay for itself under current price assumptions. Using a notional battery lease cost of $12.50 per kilowatt-month (about $3 million per year), his analysis produced a benefit/cost ratio of about 0.5 — meaning the modeled cost exceeded the modeled avoided-curtailment benefit.

The board discussed operational reliability if more load is served from Foxtail Flats rather than from dispatchable plants. Ulbrich said EDAM and the energy imbalance market (EIM) give tools to handle day-to-day deviations and that operators will retain options to keep assets like LRS available when weather or outages reduce solar output.

Hydro and tax-credit risks: Ulbrich also warned that uncertainty about tax credits and tariffs can affect the economics of Foxtail Flats and that the developer’s choice of production tax credits versus the investment tax credit may be material. He recapped that county hydropower (Abiquiu and El Vado) has variable generation and that El Vado repair work reduced hydro output and raised per-MWh costs in recent years.

The board did not take a vote on new policy in the presentation. The meeting earlier approved the evening’s agenda by a motion that passed 5–0. Ulbrich said staff will return with more detailed financial analysis and that the board will receive an EDAM tutorial to inform later decisions.