NAVFAC’s first ever solar PPA, Conti owns and operates this system to provide the military with significant electricity savings.

Naval Facilities Engineering Command (NAVFAC) teamed with Conti to create its first ever solar project using a long-term Power Purchase Agreement (PPA) to provide the Marine Corps with significant electricity savings.

Operating at net zero power from the grid had long been a goal of the US Marine Corps Logistics Base located in the Barstow desert of California. To address this, Conti worked closely with NAVFAC to develop special federal legislation enacted by Congress for a long-term PPA on a military base. The legislation, “Contracts for Energy or Fuel for Military Installations,” requires no upfront capital investment from the government. Barstow was the first solar project to use this legislation, and Conti successfully lined up the financing to make the project possible.

Under the PPA, Conti owns the project and sells the power generated to the Marine Base. The project supplies about 25% of the base’s electricity requirements and is expected to provide the Marine Corps with $3.9 million in energy savings over the 20-year term of the PPA. There are significant environmental benefits as well. The project offsets the release of 18,000 tons of greenhouse gas, which is equivalent to planting 28,000 trees and growing them for ten years.

Conti also engineered, procured and constructed the array. The solar photovoltaic (PV) system consisted of 4,452 solar panels at two separate locations on the base, generating 2.5 million kWh of electricity in the first year of operation. At the Yermo site, the 771 kWh facility consists of 2,968 modules in 212 14-panel DC electrical strings feeding two Advanced Energy 333 kW inverters. The Nebo system has a maximum DC capacity of 386 kWh and uses 1,484 modules in 14 panel DC electrical strings to feed one Advanced Energy 333 kW solar inverter. The Nebo installation had unique challenges due to the existing 1 MW wind turbine.

Conti designers developed a solution to overcome the 1 MW cap on net metering by installing relays to limit production of the PV system. Once the DC power is sent to the grid-tie inverters from both locations, it is converted to AC and stepped up to 12.47 kV to feed the base’s local distribution.