Alta Wind Energy Center (AWEC), California, United States of America

Alta Wind Energy Center (AWEC), also known as Mojave Wind Farm, is the second largest onshore wind energy project in the world. It is owned by Terra-Gen Power, an affiliate of Arclight Capital Partners and Global Infrastructure Partners.

The project will supply 1,550MW of clean renewable energy to Southern California Edison (SCE) for more than 25 years under a 3,000MW wind power development initiative upon completion. The purchase agreement was signed in 2006.

Spread across 3,200 acres in the foothills of the Tehachapi Mountains in Kern County, AWEC is located just two miles from the Tehachapi wind resource area (WRA), which consists of wind farms constructed in the 1970s and 1980s. The turbines have been installed at altitudes ranging from 3,000ft to 6,000ft above sea level in Tehachapi.

The first phase of AWEC began in July 2010. It consisted of units I to V, which were completed in April 2011. Construction of units VI and VIII began in early 2011 and building of the additional units VII and IX started in April 2012.

Terra-Gen's AWEC development

Terra-Gen took over the Alta project from Australian infrastructure fund Allco Finance Group after the company discontinued its 'Alta - Oak Creek Mojave' initiative because of bankruptcy in the early 2000s.

Terra-Gen offered $325m to the company for acquiring the project.

The project will see the installation of up to 600 wind turbines in total, serving the electricity needs of 257,000 California homes upon completion. Construction and installation of some 300 turbines is expected to start in 2015; these will generate around 830MW.

Construction of California's wind power site

The AWEC project comprises installation of up to 600 wind turbines and construction of supporting facilities, a batching plant, service roads, a power collection system, transmission lines (both overhead and underground), electrical switchyards and substations.

Other infrastructure includes communication cables with data input monitored by a SCADA system, meteorological towers, a lightning protection system and other operations and maintenance facilities.

The transmission line includes a single six-mile long 230kV line, connecting the SCE's Windhub substation.

Graders and power haulers are used for transferring the turbines to the project site.

Generating capacity of the Alta Wind Energy Center

The first phase of AWEC consisting of units I to V became operational in April 2011. Unit I has an installed capacity of 150MW and was the first unit to be connected to the Windhub substation. Unit I is installed with GE 1.5-MW SLE turbines.

Units II to V have installed capacity of 150MW, 150MW, 102MW and 168MW respectively. The four units are installed with Vestas V 90-3.0MW turbines.

Construction of units VI and VIII began in January 2011. The two units will have an installed capacity of 150MW each and use Vestas V 90-3.0MW turbines.

A total of 100 turbines will be installed for the two units, which are expected to be completed during 2012.

Units VII and IX also use the same Vestas turbines and the construction work on them started in April 2012. Their completion will increase the generating capacity of the AWEC to 1,320MW.

Financing the Californian wind farm

Financing for the $394m unit I of AWEC was completed in March 2010. It consisted of a seven-year construction and term loan, a bridge loan to the Investment Tax Credit (ITC), cash grants from the US Department of Energy and other supporting credit facilities.

Credit Agricole CIB and Nataxis of New York branch-led the financing with the other lenders being the Union Bank, Prudential Investment Management, Robobank Nederland and Banco Santander.

Financing for the $1.2bn units II to V was completed in July 2010. The four units were financed by Citibank, Barclays Capital and Credit Suisse. Google invested $55m in May 2011 in unit IV and $102m in unit V in June 2011. Citibank also invested in the unit V.

Financing for the $631m units VI and VIII was completed in June 2011, comprising of a seven-year construction and term loan, a bridge loan to the Investment Tax Credit (ITC) cash grant from the US Department of Treasury and other supporting credit facilities. It was led by Credit Agricole Corporate and Investment Bank, as well as the MUFG Power Utilities Group.

ING Capital, Robobank, Santander and RBS Securities were the joint arrangers for the funds, while the lenders included CoBank, Bank of Motreal, Key Bank, Lloyds, DZ Bank and Helaba.

Financing with a similar structure was arranged for the $650m units VII and IX in April 2012. The financing process was led by Union Bank (an affiliate of Mitsubishi-UFJ Financial Group) and RBA Securities. The joint lead arrangers were Bank of Montreal, Canadian Imperial Bank of Commerce, Key Bank, KfW IPEX Bank and Santander, while the lenders were Sumitomo, BayernLB, DZ Bank and Associated Bank.

Contractors for the Alta Wind Energy Center (AWEC)

The first unit was constructed by a joint venture of Wind Energy Constructors and Balfour Beatty.

The unit was acquired by GE and Bankers Commercial with shares of 50% each in 2011.

Blattner Energy is responsible for leading the construction of units VI and VIII with the two expected to be operational by the second half of 2012.

Unit VI of AWEC was sold to EverPower, a subsidiary of Terra Firma, in April 2012, while Unit VIII was sold to Brookfield.

Blattner Energy is responsible for carrying out the construction work of units VII and IX, with construction work expected to be completed by the fourth quarter of 2012.