Photovoltaic & Energy Efficiency Improvements for NAVFAC

As managing partner of Atlantic Contingency Constructors, Inc., APTIM led a photovoltaic (PV) and energy efficiency design-build project for the Naval Facilities Engineering Command (NAVFAC).

Sites Investigations/Energy Audits: The project team performed site investigations and energy audits of 381 buildings on 19 naval bases throughout Texas, Mississippi, Florida, Virginia, Maryland and Washington, D.C. Working closely with the client, the investigations and audits were executed in just 12 weeks and with minimal impact to military operations. Upon completion, the project team identified PV, solar thermal and lighting upgrades that could potentially provide more than 9,000,000 kWh in annual electrical energy savings.

Energy Systems Design: Based on the project team’s initial analysis, the Navy requested the design and construction of 72 recommended improvements, including: – A 100-kilowatt (kW) PV rooftop system to offset daytime electrical loads for the Reserve Training Center at Naval Support Facility Anacostia (Building 351) – Nominal 50-kW rooftop PV systems to reduce the cost of purchased power at 15 separate buildings at Naval Air Station Key West – A 600-kW rooftop PV system for a warehouse building at Jacksonville Naval Station to help meet daytime electrical loads and potentially reduce the need for capacity increase in the power distribution infrastructure – A 2,100-kW ground array PV system at Norfolk Navy Base that ties into the power grid and meets two percent of the average daytime load, thereby reducing power costs; the 10-acre solar farm consists of 8,600 panels, each supported by an H-pile network tied into the base grid through an underground feed system more than a mile long. The design phase work included 100 percent design packages for each system selected by the Navy for installation. The design packages consisted of structural roof upgrades and roof replacements; electric panel sizing and placement; utility interconnection design and negotiation; optimization of PV output to inverter sizing; balancing of system components; production of compatible amperage; adequate LED lighting sources; and efficient tie-in to onsite grid connections.

Construction/Installation: Following Navy approval of site designs, the project team constructed and installed the rooftop and ground-mounted PV systems, solar thermal systems and LED lighting systems, which ranged in size from 50 to 3,000 kW. The fast-track effort took approximately two years and required working at multiple installations simultaneously.

Through effective management of energy audits, system design and construction, the project team was able to stretch the client’s budget, ultimately allowing for the purchase and installation of additional PV equipment. Conservative estimates, using the National Renewable Energy Laboratory calculator, show a total annual energy savings for the Navy in excess of 9,000,000 kilowatt-hours.