Barrett Street 16.5 MW Ground Mount Solar Project

Fuss & O’Neill was contracted to provide electrical engineering services to support the electrical design for his 16.5 MW DC solar electric generating facility in Oxford, MA.

In the planning stages, Fuss & O’Neill provided initial concept sizing and planning, and then continued through detailed design and construction. The team met strict deadlines and requirements to qualify for energy tax credits by grouping bunches of 20 to 200 small subarrays that make up 12 larger array sites. The project’s 1,100 subarrays were all built in one location before being separated electrically and designated to their own string inverters, which convert DC power to AC power, to make a mini subarray system. The system includes more than 1,000 string inverters.

To avoid delays, the team developed a predrill-and-drive installation process for the arrays’ H-piles. This allowed for the racking H-pile foundations to be used where there were obstructions such as cobblestones and ledge rock near the surface, which made it difficult to drill. Rather than removing the subsurface obstructions and regrading the land, the team used the predrill-and-drive process to arrange the H-piles so that they could install them evenly over the uneven terrain.