Concentrating Photo-Voltaic System for DoD Rooftop Installations
Deborah Jelen | Electricore, Inc.
Objectives of the Demonstration
Electricore, Inc. (Electricore), in teaming with Suncore Photovoltaic, Inc. (Suncore) and Morrow Meadows, conducted a 15-month demonstration of a 50 kilowatt (kW) Concentrating Photo-Voltaic (CPV) solar system at Naval Air Weapons Station (NAWS), China Lake, California. The installation was conducted over two phases allowing for 1 full year of seasonal data collection on both systems; the Suncore 25kW SE-500X system was demonstrated for the full 15 months and the Suncore 25kW Soliant 1000 system was demonstrated for 12 months.
The primary objective of this project was to demonstrate Suncore’s high-performance and high-efficiency CPV solar panels through the installation and operation of both the Suncore 25kW SE-500X system and Suncore 25kW Soliant 1000 system at NAWS China Lake. The project also sought to help quantify the operational and cost benefits of the CPV technology for future application with Department of Defense (DoD) customers.
Key performance objectives included annual energy production, greenhouse gas (GHG) emissions, system availability, and levelized cost of energy (LCOE). To date, the system has delivered 93,725 kilowatt-hours (kWh) of energy, which equates to a savings of more than 7,237 gallons of gasoline or 64 tons of carbon dioxide (CO2).
Each SE-500X panel included six 22.5% efficient solar modules and each Soliant 1000 panel included eight 25.3% efficient solar modules. Both will produce electricity at parity with the statewide average retail grid price of electricity for commercial users. The system was engineered specifically for rooftops in hot, dry, sunny areas using high-efficiency cells and dual-axis TipTilt Tracking™. NAWS China Lake was an ideal location to test and demonstrate this type of system, given the area’s high Direct Normal Irradiance (DNI) and multiple sunny days. This technology can also be easily replicated at virtually all DoD installations and other government facilities in the Southwest United States, specifically the areas with similar climate profiles to NAWS China Lake.
Suncore also developed an integrated racking product for the Soliant 1000 panels. The rack is utilized for both transport of the panels as well as the system’s installation.
For typical large commercial users, the Suncore product offering will result in a payback of less than 7 years; however, under this demonstration the payback profiles were not demonstrated. The solar manufacturer has outlined the required cost elements and typical payback values should the technology be installed at another site. Many military and DoD installations will have different cost/payback profiles since the DoD is not always eligible for most solar incentives or rebates as noted under this project.
Throughout the demonstration, the Electricore Team, ESTCP, and NAWS China Lake personnel were able to monitor the system performance via Deck’s online interactive monitoring service. The Team conducted a qualitative and quantitative analysis of the system, including customer feedback from NAWS China Lake personnel. Most performance objectives were met with the exception of Annual Energy and Payback. This system offset more than 69,693 kWh of energy demand annually from the grid and contributed 42kW alternative current (AC) of on-site renewable energy generation. The system showed 98% availability and had an estimated LCOE of $0.17/kWh.
Overall, the performance of the system was adequate for Phase 2, but less than expected for Phase 1. This can be attributed to the initial installation errors made by the solar installer and the use of the now discontinued SE-500X model CPV tracker unit in Phase 1. Installed costs (without the cost overrun) are consistent with similar sized commercial photo-voltaic (PV) systems, when compared to California solar statistics in 2010 when the project was initially proposed. The estimated cost of the CPV module/tracker for a turnkey system on a typical roof is $3-$4/Watt (W) for future installations.
This project helped quantify the operational and cost benefits of the CPV technology for future application at other DoD installations. The CPV technology was installed at an existing DoD building with minimum changes to existing infrastructure. The technology yields several specific and measurable benefits, including offset energy demand from the grid, reduced energy costs, and decreased carbon emissions. Suncore’s CPV systems are well suited for the high DNI areas of the Southwest United States and provide DoD installations a cost effective, high-efficiency PV solution for multiple regions.