Callisto II Energy Center in Houston, TX

Callisto II Energy Center is a new construction project located at 12100 Hiram Clarke Rd in Houston, Harris County. The facility is designed as a 300MW 2-hour battery energy storage plant with an accompanying substation to interconnect with the utility grid. The total estimated cost for the project is $57,500,000, covering a site area of 550,000 sq ft. This valuation places the cost per square foot at $105, which is above the Harris County median of $88 for similar new construction filings.

Project Scope and Design

The scope of work includes the construction of private access roads, civil and drainage systems, foundations, and a water line for the fire protection system. Callisto II Energy Center LLC is the owner of record, while Electrical Consultants, Inc. is listed as the design firm. The project is privately funded and situated on private land for private use. A third-party source, theorbitdesk.com, describes the facility as a 400 MW battery storage power plant, though the TDLR filing specifies a 300MW capacity. The registered accessibility specialist for the project is Blair Baker.

The project was registered with TDLR in October 2025. The filing indicated a construction start date of November 2025 and a target completion date of August 2026. The scheduled build window of 271 days is close to the county median of 219 days.

Current Status and Records

City of Houston permit records show two permits on file at this street address, issued between March 2026 and May 2026. These permits are for utility power equipment pads and substation foundation pads with sitework, referencing the 2021 IBC. However, the TDLR status remains Project Registered. No plan review or inspection has been recorded since the initial registration, so whether construction proceeded as scheduled is not confirmed in the public record. The completion date listed on the filing has passed, but there is no official record of final inspection or closure.

In the surrounding area, other registered projects include the Union Plumbing Warehouse, On Go, and the Sims Bayou Greenway Segment S104B. The local labor market in Harris County showed an unemployment rate of 5.4 percent in June 2026, which was higher than a year earlier. Census estimates for the 77045 ZIP code report a population of about 32,482 and a median household income of $61,166.