Interactive Resources, Inc. was retained by Perpetual Power LLC to provide structural engineering services for the design of two roof mounted solar arrays and one ground mounted array at the existing Deer Island Treatment Plant facilities in Winthrop, Massachusetts. Design services included verification that the existing framing could support the array and the preparation of structural calculations for the anchorage of the roof-mounted and ground mounted inverter and construction of a concrete pad. The design portion also included preparation of structural drawings showing the location and details for the inverter anchorage. Responded to code enforcement agency comments.