Blue Wing is a solar photovoltaic (PV) installation located near the    intersection of IH 37 and U.S. 181 southeast of San Antonio.

Duke Energy Generation Services, a commercial business unit of Duke Energy.

CPS Energy as a municipally (non-profit) owned utility would not be able to take advantage of any tax credits that are currently offered to private businesses for developing renewable energy facilities.

16.6 megawatts (DC), or 14.4 megawatts (AC). This includes a 500-kilowatt (kW) demonstration facility where multiple photovoltaic modules and a concentrating PV unit have been installed for research and comparison purposes. 

The estimated amount of generation from the facility is approximately 25,000 megawatt-hours.

Approximately 1,800 houses in CPS Energy’s service territory.

An estimated 18,200 tons of GHG emissions will be offset each year.

Duke Energy Generation Services owns the 113 acres where the solar farm is located.

CPS Energy has a power purchase agreement for electrical generation from Blue Wing for 30 years.

CPS Energy solicited competitive bids for a solar project in 2008 and ultimately selected juwi solar Inc. to negotiate the power purchase agreement.

Duke Energy Generation Services selected juwi solar Inc. to provide these services for the facility during the initial years.   San Antonio-based subcontractors will provide electrical and landscaping maintenance services for the project.

juwi solar Inc. acted as the engineering, procurement and construction contractor. Newkirk Electrical Associates acted as the prime subcontractor. Several San Antonio companies and residents were employed to provide consulting services and labor for the project.

Construction began in March 2010. The farm began full operations on November 4, nearly two months ahead of schedule.

The modules are rated to withstand hail up to one inch in diameter.

Thin film photovoltaic modules offer a lower cost PV solution that perform well in diffuse light conditions such as the hazy mornings in San Antonio. They also perform well under high heat conditions where crystalline modules experience a greater efficiency loss. Thin film modules require less energy and raw materials to manufacture and have a lower life-cycle environmental impact than crystalline modules.

First Solar is the module supplier. SMA is the inverter supplier.

It is very unlikely for modules to be hit by lightning due to the fact that there are 24 lightning poles distributed around the site to collect lightning strikes.  If a module is hit, it is very unlikely that more than one array (50 modules) will be affected.  The lightning strike is kept isolated because every array is grounded and lightning always seeks the lowest potential contact which is ground. On site we have over 12,000 rack posts in the ground, 200 ground rods and over 100,000 ft. of ground cable.

Approximately six feet in depth.

A 500 kW system comprising of eight different solar technologies – one concentrating photovoltaic system, five systems consisting of thin-film modules from different suppliers and two systems consisting of crystalline modules. 

The 50-foot tall tower is a concentrating photovoltaic unit that tracks the sun’s movement.

Adding solar to CPS Energy’s well-balanced energy portfolio will help CPS Energy achieve its ambitious goal of having 1,500 MW of renewable energy capacity in its resource portfolio by 2020.

Item = Quantity
Modules = 223,900 (includes demonstration; 214,500 main)
Racks = 4444 (+1 CPV system)
Power Stations = 11
Inverters = 22 (+8 demonstration facility)
Road Length = 6,684’
Fence Length = 12,450’
Power = 16,087,500W DC + 618,720W DC (demo)
Acreage = 113 (project), 140 (site)
Array Tilt = 20 degrees
Array Azimuth = 25 degrees west of south

Generally speaking, SCADA, RTUs and communications were installed at the entrance of the property on the installed poles.  Dedicated fiber cables were installed from CPSE’s Brooks substation for communications (RTU & meters) and SEL mirrored bits used for direct transfer trip (DTT) signal.  The PV system is monitored by JUWI system operators.  If a fault occurs on CPSE feeders, substation feeder breaker trips and sends a DTT to open reclosers (RE) until system voltage is stable.  The facility has a protection setup to disable the PV plant from islanding.  After CPSE fault, power stations will shut down inverters disconnecting the solar arrays from grid until CPSE voltage is sensed at power station.  Automatic close logic in reclosers that allows CPSE to give permission to REs to close after CPSE fault.  This logic monitors CPSE voltage and frequency to ensure stability before requesting permission.  If fault occurs in PV plant the associated Power Station will clear and isolate the faulted section.

The step-up transformers are 315V-Wye / 13.2kV-Delta.  Each Power Station contains 2 – 675kVA transformers.