Illustrative letter. Names are fictional. The operating facts are the Pecos case: 50 MW of IT at an existing solar interconnection, peak import 54 MW — under ERCOT’s 75 MW Large Load threshold.
Sierra Mesa Computing, LLC
Grid and Energy
2200 Post Oak Boulevard, Suite 1400
Houston, Texas 77056
28 August 2026
Interconnecting Transmission Service Provider
Copy: Director, Resource Integration
Copy: Director, System Planning
Electric Reliability Council of Texas, Inc.
8000 Metropolis Drive, Building E, Suite 100
Austin, Texas 78744Copy: Qualified Scheduling Entity for Sierra Mesa Computing
Re: Co-located computing load under 75 MW — Mesa Flats Solar, Pecos County, Texas.
Load Information Form and request for TSP coordination.
Dear Sir or Madam:
Sierra Mesa Computing, LLC requests interconnection of 50 MW of computing load co-located with Mesa Flats Solar, an existing Generation Resource in Pecos County. Peak demand at the point of interconnection is approximately 54 MW, including site auxiliary. Enclosed is the Load Information Form for co-located load under 75 MW, for coordination by the interconnecting TSP and ERCOT.
This is a differentiated load addition at an existing generation interconnection. The plant is already in service. The hall uses power the array is already producing. Peak import remains below ERCOT’s 75 MW Large Load threshold. The load will be registered as a Controllable Load Resource.
- Interconnection
- Existing, energized generation POI. Co-located with the solar resource and battery already at the site. No new transmission line and no new generation interconnection.
- Peak demand
- 50 MW of contracted computing load. About 54 MW at the meter with auxiliary. Below the 75 MW Large Load threshold.
- Day / night
- During solar hours the hall is served from the existing array; net interchange at the POI falls. Overnight import is a bounded 54 MW service.
- Water
- Closed-loop, air- and ground-coupled cooling. Negligible makeup. No evaporative towers. No community potable water for cooling. No new water right.
- Noise
- Heat rejection is distributed across the existing tracker field. No new cooling-tower cell and no new chiller yard. Operating sound is pumps and a dry-cooler fail-safe, in keeping with the solar plant already there.
- Emissions
- Grid-tied operation uses no on-site combustion. If the site later islands, on-site generation is about 22 MW in summer and 28 MW in winter — residual after solar, storage, and recovered heat — not a 54 MW engine plant. That is roughly half the air-permit, noise, and fuel envelope.
- Load reduction
- The load will respond to ERCOT instruction as a Controllable Load Resource, including curtailment and ramping consistent with Protocols for loads 25 MW or greater. The battery at the POI will be offered through our QSE for ancillary services ERCOT already procures.
- Islanding
- The electrical and thermal design allows the 50 MW hall to run islanded if firm overnight service is not available on the customer’s schedule. Islanding is an option. It is not required to energize the load.
We request that the interconnecting TSP coordinate this addition as co-located load under 75 MW, identify any studies required before energization, and confirm the path with ERCOT Resource Integration. We will provide the load model applicable to facilities 25 MW or greater, and any water, cooling, and community-impact information the Commission or ERCOT requests of computational load.
We are prepared to brief the TSP and ERCOT on the net-interchange profile, controllable-load capability, and the closed-loop cooling design.
Respectfully submitted,
Alexandra V. Chen
Vice President, Grid and Energy
Sierra Mesa Computing, LLC
Enclosure: Load Information Form — co-located load under 75 MW
cc: Qualified Scheduling Entity
Modeled on ERCOT’s Load Information Form for co-located load under 75 MW. The interconnecting TSP files with ERCOT. Names are fictional.