Foxtail Flats: Solar Power and Battery Storage

This project will produce 170 MW/hour, which is more than enough to supply the daytime load for the Los Alamos Power Pool (LAPP), which is a partnership that combines the energy needs and resources for Los Alamos County (LAC) and Los Alamos National Laboratory (LANL). DPU plans to sell 50 MW/hour over 10 years under a separate Power Purchase Agreement (PPA) with Mercuria. This will leave 120 MW/hour for LAPP, which will serve load and charge the Battery Energy Storage System (BESS). If appropriate, DPU may enter into additional separate agreements with third parties to sell excess power as needed. 

How much energy will the battery store? How long will it provide power if used?

The BESS is an 80 MW system with capacity of 4 hours. In other words, it can discharge 80 MW of power per hour and hold up to 320 MW of power.

The daytime power is relatively inexpensive at $37.88/MW for the entire 20-year term of the project. That being said, the BESS is more costly due to lack of storage technology. The blended cost for the combined resource is about $74/MW, which is a little bit less than current PPA pricing. 

We should start receiving power toward the end of 2026.

Power will flow from San Juan's 345 KV transmission line directly onto PNM's system. LAC will use its existing contract with PNM to transport power to LAPP. 

The battery will serve two purposes. It will help to supply night load of up to 320 MW for LAPP and potentially Sandia/Kirtland. The second purpose is economic. The battery will be used to sink (or store) any excess generated solar above our load, which will help DPU avoid selling solar during times of abundance when prices are low.

Our day-ahead and real-time scheduling desk will purchase power from suppliers to make up the difference. This is already a regular operational task under DPU's Electric Production division, not an unusual circumstance resulting from the project.

DESRI, owner of Foxtail Flats.