Catalina Solar Power Plant, United States of America
EDF Renewable Energy's Catalina power project uses solar photovoltaic technology to produce clean energy for 35,000 homes. The 143MW plant is located in Kern County, California, and is co-owned by GE Energy Financial Services, MetLife, Union Bank and Citi, which purchased equity stakes in the project in January 2013.
EDF Renewable Energy developed the photovoltaic power plant in two phases, including 60MW first phase and 83MW second phase. Construction on the project started in May 2012 and the first and second phases were completed respectively in December 2012 and September 2013.
San Diego Gas & Electric (SDG&E) purchases the power generated from the project under a 25-year power purchase agreement (PPA) signed with the developer in June 2011. The renewable project offsets approximately 250,000t of greenhouse gas emissions annually.
Development of the Californian solar power plant
The solar power plant was an integral part of EDF Renewable Energy's solar-wind hybrid project aimed at generating power from both wind and solar sources in the Tehachapi-Mojave region of Kern County. The power generated from the hybrid project was planned to be fed to the Southern California Edison's (SCE) grid through shared transmission infrastructure.
The hybrid project included the 140MW Pacific wind farm located adjacent to the solar power plant. The wind farm started producing power in August 2012.
EDF awarded the engineering, procurement and construction (EPC) contract for the solar power plant in April 2012 and achieved financial closure for the project in January 2013. The plant became operational in September 2013.
Location details of the solar power project
The plant is developed on 445ha of privately owned land in the Mojave Desert of California. The site is situated south-west of the Tehachapi and Piute mountains, in close proximity to the local transmission network.
The plant comprises more than 1.1million photovoltaic modules mounted overground. The modules produce alternating current, which is converted into direct current using central inverters.
A 7.2mi (11.6km), 230kV transmission line transmits the power to SCE's Whirlwind substation.
Technology employed at the solar PV power plant
The PV modules installed at the plant are made of cadmium telluride (CdTe) and Copper-Indium-Gallium-Selenium (CIGS) supplied by First Solar and Solar Frontier respectively.
The CdTe panels, which contain semiconductor material composed of cadmium and tellurium in a thin layer on a glass sheet surface, account for 61MW whereas the remaining panels are of CIGS type. The principal advantage of CdTe technology over crystalline silicon modules is cost-efficiency. The composite materials in the CIGS panel include tetrahedrally bonded copper, indium, gallium and selenium on glass sheets coated with molybdenum.
The semiconductor compound material on the CIGS panel absorbs light, creating holes and electrons which diffuse in the CIGS grains creating an electric field. The electrons move into the transparent conducting oxide layer thereby developing a voltage between the ZnO/CdS electrode and the molybdenum base electrode.
The panels installed at the plant have better resistance to heat compared to silicon-based solar panels.
Key players involved with the Catalina photovoltaic solar power plant
Bechtel provided EPC services and built the transmission line. SMA supplied the power conversion system including the central inverters and transformers.