El Arrayán Wind Farm, Chile
The 115MW El Arrayán wind power plant will be the largest wind energy facility in Chile once complete. Located about 400km north of Santiago in the coastal zone of Ovalle, the project was developed by Parque Eolico El Arrayan, a joint venture between Pattern Energy and Antofagasta Minerals.
Pattern Energy, the operator of the wind farm initially had a net ownership interest of 31.5% in the project, while AEI and Antofagasta Minerals held 38.5% and 30% respectively. Pattern however bought AEI's stake in the project increasing its interest to 70%. The wind farm is now jointly owned by Pattern Energy (70%) and Antofagasta Minerals (30%).
Construction works started in May 2012 and the first turbine was erected on 29 October 2013. The wind farm became commercially operational in June 2014. It will generate power equivalent to the electricity needs of around 200,000 local homes, and created 200 jobs during construction.
The renewable power project will offset the emission of around 320 million tonnes of CO2, while helping to meet Chile's goal of producing 20% of its energy from non-conventional renewable sources by 2020.
Financing for the El Arrayán wind project
The finance for the $245m wind farm was secured in May 2012. Eksport Kredit Fonden, Bank of Tokyo-Mitsubishi UFJ, Credit Agricole, Sumitomo Mitsui Banking, and local bank Corpbanca are providing funds for the project.
El Arrayán wind farm make up
Located in the farmlands of El Arrayán and El Sauce, the wind power plant utilises the coastal wind resource of the region.
The West of Duddon Sands (WoDS) wind farm is a 389MW offshore wind power project located in the East Irish Sea.
The farm is installed with 50 2.3MW turbines mounted on 80m-high towers. There is also a control and maintenance building for the plant.
The three-bladed wind turbines have a rotor diameter of 101m and blade length of 49m. The swept area of each turbine is 8,011.8m². The rotor speed varies from 6rpm to 16rpm. The power output of the rotor is guided by pitch regulation.
Each turbine is equipped with hydraulic disc brake, a 2,300kW asynchronous generator, and a three-stage planetary / helical gear box.
The turbines for the wind farm were manufactured at Siemens' facility in the US. Siemens installed and commissioned the wind turbines, and provides service and maintenance for five years.
Grid connection and distribution
Power from the aero generators of the turbines passes through in-tower wires and is connected with the 35kV/0.690kV power transformer located on ground near tower foundation. It is then transmitted through a 35kV line before it is stepped up at the 220kV/ 35kV El Arrayán substation.
A 220kV transmission line from the plant's substation and a new lift substation for connection to the electricity grid are also be built as part of the El Arrayán wind power project.
The power output of the El Arrayán wind farm is fed into the national power grid Sistema Interconectado Central (SIC).
In November 2011, the JV signed a 20-year power purchase agreement with Minera Los Pelambres, a subsidiary of Antofagasta Minerals, for the sale of power generated by the wind farm.
Minera Los Pelambres, one of the world's biggest copper mines, has signed a long-term power purchase agreement to buy approximately 70% of the wind farm's output. The remaining 30% output will be sold in the Chilean spot market.
Contractors involved with the El Arrayán wind project
Skanska was awarded the construction contract worth $76m for the wind farm in March 2012. The scope of the contract includes planning, design, procurement and construction of roads, foundations, buildings, and electrical infrastructure, including two substations and a 220kV transmission line.
Siemens received an order for the supply of wind turbines in May 2012. It was the first Chilean wind turbines order for Siemens.