Barrett Street 16.5-MW Ground Mount Solar Photovoltaic Array
Oxford, Mass.  
Award of Merit

Owner: BlueWave Capital LLC
Lead Designer: Fuss & O’Neill
General Contractor: Conti Enterprises Inc.
Civil Engineer: Andrews Survey & Engineering Inc.
Structural Engineer: RBI Solar
Environmental Consultant: Eco Tec Inc.

The 16.5-MW-capacity solar photovoltaic array sited on a former 130-acre hog ranch is more than twice the size of most of New England’s solar energy installations. 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 team worked on multiple arrays concurrently to deliver the seven-month project on time while meeting all contract requirements and regulations beyond the scope of work. The system includes more than 1,000 string inverters.

The 12 systems are tied into two interconnection points in a remote location, miles from the farthest array. Some of the conduit had to be buried using directional boring to avoid damaging wetlands. The wet muddy site was a challenge during construction.

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.

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