This 38 kW building-integrated PV system (inside black line) at Western’s Elverta Maintenance Facility supplements the 40 kW system installed at Elverta in 1996. Both systems completely cover the Elverta roof and are the largest PV application of its kind in the continental United States. Phase II is totally funded and owned by Western. It consists of 762 Solarex Millennia PV modules (43 Watts each) and 264 APS modules (22 Watts each). Both PV types utilize thin film amorphous silicon technology.

The DC output from the PV modules are converted to 110 volt AC by a 32 kW Trace inverter, and then stepped up to 480 volt, three phase AC by a 45 KVA transformer for direct connection to the building’s service panel. Besides replacing grid power, the Powerlight system protects the roof membrane for longer life and provides R10 insulation to reduce the cooling and heating loads, thereby decreasing energy consumption.

Facility Information

• System & Building Owner: Western Area Power
• Site Location: Elverta, CA

Contractor

• System Integrator: Power light

Schedule

• Installation Completed: June 1998
• Construction Duration: 3 weeks

Performance Parameters

• Power Capacity: 38.6 kW peak DC; 27.8 kW AC
• Annual Energy (est.): 67,500 kWh/year
• Lifetime CO, Savings: 2300 tons
• NOX: 8.7 tons
• SOX: 16.4 tons
• Life Expectancy: 20 years

Electrical Design

• AC Output: 110 V stepped up to 480 V, 3 phase
• PV Configuration:
  • Solarex: 3 series, 254 parallel
  • APS: 12 series, 22 parallel
• Number of Strings: 276
• DC Current and Voltage (per string): 0.6A @ 210V
• Inverter: Trace, 32 kW (AC)
• Transformer: 45 kVA

PV Roof Tiles

• PV Cell Material: Solarex Millenia a-si*, 43W, APS a-si, 22W
• No. PV Modules: Solarex 762, APS 264, Total 1026
• Module Size: Solarex 26”x48”, APS 30”x60”
• Insulation Value: R10 (Powerguard Module), *a-si: amorphous silicon