Wind Purchases

As of January 2012, TVA has entered into nine contracts with eight wind farms for the purchase of 1,515 megawatts of energy.

Two of the contracts – with EDP Renewables in Iowa and Iberdrola Renewables in Illinois – have been providing energy to TVA since 2010.

Four renewable wind power sources began delivery to the TVA power grid in January 2012:

• ENEL Green Power in Kansas
• NextEra Energy Resources in Illinois
• EDP Renewables North America in Iowa
• and an additional contract with EDP Renewables original Iowa site that has been producing wind energy for TVA since 2010.

Other contracts with wind facilities in Illinois and Kansas are expected to begin delivery in calendar year 2012, subject to satisfying applicable environmental requirements and securing firm transmission paths. The new wind contracts are competitive with forecasted electricity market prices and are the result of a TVA request for proposals in December 2008.

CPV Renewable Energy Company

CPV Renewable Energy Company will supply 165 megawatts of wind energy. The energy will come from its Cimarron wind farm in Gray County, Kan., generated by Siemens Power Generation SWT-2.3-93 2.3-megawatt wind turbines. Construction began in 2011 with generation beginning in late 2012. CPV will manage the facility.

EDP Renewables North America LLC

In September 2010, EDP Renewables North America LLC began supplying 115 megawatts from its Pioneer Prairie wind farm in Howard and Mitchell counties in Iowa. In January 2012, an additional 83 megawatts was supplied from the same facility.

With that, TVA has contracted for all 198 megawatts of the facility's output, generated by 131 Vesta 1.65-megawatt turbines. An additional contract for 101 megawatts also began delivering energy in January 2012 from the Lost Lakes wind farm.

ENEL Green Power, LLC

In January 2012, ENEL Green Power, LLC began supplying 201 megawatts from its Caney River wind farm in Elk County, Kan. The power is generated by 111 Vesta turbines.

Iberdrola Renewables

Iberdrola Renewables began supplying 300 megawatts from its Streator-Cayuga Ridge wind farm in Livingston County, Ill., in May 2010. The power is being generated by 150 Gamesa turbines.

TVA does not currently receive renewable energy from this facility, as its Renewable Energy Credits are not currently supplied to TVA. The facility's owner has the rights to the environmental attributes and may sell these attributes to other parties. When TVA exercises its contractual option or a Federal Renewable Energy Standard is enacted, TVA will have the right to the Renewable Energy Credits associated with the facility.

Invenergy LLC

Invenergy LLC will supply 400 megawatts of wind energy:

• The Bishop Hill Wind Energy Center in Henry County, Ill., will provide 200 megawatts generated by 134 General Electric 1.5-megawatt SLE turbines.
• The California Ridge Wind Energy Center in Champaign County, Ill., will supply 200 megawatts from 134 General Electric 1.6-megawatt turbines. Construction started in 2011, with generation beginning in 2012. Invenergy will manage the facilities.

NextEra Energy Resources, LLC

NextEra Energy Resources, LLC began providing 150 megawatts from its White Oak Energy Center in McLean County, Ill in January 2012. This energy is generated from 100 General Electric 1.5-MW SLE turbines.

Background

A wind energy system transforms the kinetic energy of the wind into mechanical or electrical energy. The output of a wind turbine depends on the turbine's size and the wind's speed through the rotor. Wind turbines being manufactured today have power ratings from 1 to 3 megawatts. These can be used as a single unit or grouped together to form large-scale wind farms.

The capacity factor, or productivity, of a wind turbine normally ranges from 25 percent to 40 percent, although higher capacity factors can be achieved during windy periods. The capacity factor is determined by comparing actual production with the amount of power that would have been produced if the turbine were able to operate at maximum output 100 percent of the time.