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High-Voltage Transmission for Wind Moving Forward in Kansas, Oklahoma

Dec 15, 2008 - Wind Energy Weekly

Two high-voltage transmission lines that could integrate up to 5,800 MW of wind power took a significant step forward recently with approval of the projects’ transmission rate incentives by the Federal Energy Regulatory Commission.

The two projects, known as Tallgrass and Prairie Wind, include 400 miles of 765-kV transmission lines crossing Southern Kansas and the Oklahoma panhandle. The lines will become operational in 2013 if remaining permits are granted and cost allocation agreements reached according to plan.

The two projects will operate within the footprint of the Southwest Power Pool (SPP), the regional transmission organization for the Southern Plains. There are currently more than 40,000 MW of wind projects seeking interconnection to the grid in this region. SPP has taken a lead role in reforming the way transmission is planned and paid for to better facilitate the construction of transmission used in integrating wind projects.

The Prairie Wind and Tallgrass projects would become the highest-voltage transmission lines to operate west of the Mississippi River. Currently, more than 2,100 miles of 765-kV transmission is operational in Ohio, Indiana, Kentucky, West Virginia, and Virginia, although most of the U.S. grid operates at voltages of 500-kV and below.

There are significant cost and efficiency advantages to building transmission lines at higher voltages. In fact, a 765-kV line can carry as much electricity as six 345-kV lines, at 1/3rd the cost, using 1/4th as much land, and with 1/10th the line losses.

A recent analysis by the consulting firm Charles River Associates International found that a high-voltage transmission network in the SPP region, of which the Prairie Wind and Tallgrass lines are the first phase, would generate significant benefits for the region. According to the study, the project would yield savings of around $1 billion per year, more than twice the $400-500 million annual cost of the transmission investment. The new transmission infrastructure could bring 14,000 MW of new wind plants online, reducing carbon dioxide emissions by 30 million tons per year. The transmission project, combined with the associated wind farm development, would also create 10,000 construction jobs and 5,000 new permanent jobs, $60 million in annual property tax revenue, and $500 million in economic activity each year.

The Tallgrass project is a joint venture between OGE Transmission, LLC, and Electric Transmission America, which is a joint venture between AEP Transmission and MidAmerican Energy. Prairie Wind is a joint venture between Westar Energy and Electric Transmission America.