Black & Veatch Completes 150MWdc Three W Solar Project
The Mitsui-owned solar development has reached substantial completion and received ERCOT approval for grid connection, enabling turnover to the owner’s operations and maintenance team.
Black & Veatch has announced substantial completion of Three W Solar, a utility-scale generation project near Hillsboro in Hill County. The September 29 announcement also confirms ERCOT approval for connection to the grid, enabling the transition toward turnover to Mitsui’s operations and maintenance organization.
The development occupies approximately 875 acres and has a rated capacity of 150MWdc, equivalent to 110MWac on the alternating-current side. It represents Mitsui’s first utility-scale solar project in the United States, with Black & Veatch responsible for engineering, procurement and construction.
Project at a Glance
- Owner:
- Mitsui & Co.
- Original developer:
- OCI Solar Power
- EPC Contractor:
- Black & Veatch
- Capacity:
- 150MWdc / 110MWac
- Site:
- Approximately 875 acres
- Status:
- Substantial completion; grid-connection approval secured
From development to construction delivery
OCI Solar Power originated the project before its transfer to Mitsui. Black & Veatch’s project-management and construction activity dates from 2024, with the latest announcement marking the move from field delivery toward owner operation.
That sequence separates the original development role from the EPC assignment and long-term ownership. OCI’s involvement in bringing the project forward does not make it the construction contractor, while Mitsui’s ownership is distinct from Black & Veatch’s delivery role.
More than the solar array
Black & Veatch’s work covered the generating facility and collector-substation infrastructure. The construction scope included racking piles, a generator step-up transformer and commissioning, linking the physical solar installation with the electrical systems required to deliver its output.
The substation and transformer scope is a significant part of the construction story. Installing panels is only one stage of creating an operating generation facility; the collection and connection equipment must also be delivered and tested as part of the project.
What the capacity figures mean
The 150MWdc and 110MWac ratings refer to different sides of the same facility. They are not two separate generation projects and should not be combined into a 260MW total. The direct-current figure describes the solar-side rating, while the alternating-current figure describes the AC capacity.
The reported acreage likewise describes the overall project site rather than a building footprint. Three W is a generation development spread across a large land area, with electrical infrastructure supporting the solar field.
A transition into operation
Substantial completion and grid-connection approval are distinct milestones. The first concerns construction progress; the second allows the facility to connect to the power system and supports the final handover to the owner’s operating team.
The announcement therefore marks a confirmed EPC completion milestone with operational turnover underway. It should not be read as a claim that the plant has already completed a full period of commercial operation. For the construction team, attention now shifts from building and commissioning the asset to closing out the work and supporting the handover.