ClearWorld August Publication: Largo, Florida Goes Green - Page 13

U.S. Cities Expected To Tie All Electric Grid Systems Together

The U.S. electrical grid is really made up of three largely separate grids with puny transmission connections at the seams. These seams cross sparsely populated rangeland in the middle of the country.

The Eastern Interconnection serves much of the United States east of the Great Plains. The Western Interconnection covers residents from the Great Plains to the Rockies and up and down the West Coast. And most of Texas has a grid of its own. Policymakers there shun ties with the other two grids in order to keep federal electric power regulation out of the Lone Star State.

Almost like safety pins holding together an elaborate wedding dress, no more than 1,300 megawatts of transmission capacity at a total of seven locations stitch all of this together.

The seams have long interested electric transmission and generation planners. Nearly 100 years ago, a Chicago newspaper trumpeted the value of a truly interconnected grid. Other studies have reached similar conclusions, and the most recent effort is no different.

Led by researchers at the U.S. Energy Department’s National Renewable Energy Laboratory, a new seam study finds considerable economic and engineering value in fortifying these connections to better distribute power resources around the country.

The study results [PDF] were presented in July at the TransGrid-X Symposium at Iowa State University in Ames, Iowa.

The timing is right for this latest study to consider how to bridge the seams more robustly, says Aaron Bloom, who led the NREL research effort.

For one thing, equipment at the connection points is 30 to 40 years old, and nearing the end of its useful life. High-voltage direct current (HVDC) technology is readily available and increasingly affordable, and could replace the old equipment to make long-distance electric power transfers between the eastern and western United States possible.

The rapid growth of wind and solar generation has also kindled talk about using those resources more effectively. Ideas put forward in the 1920s cited abundant hydroelectric resources in the West and coal resources in the East as reasons for building a robust east-west grid to move electricity produced from those resources to growing markets.

Bloom and colleagues from Iowa State, Pacific Northwest National Labs, the Southwest Power Pool, the Midcontinent Independent System Operator, and the Western Area Power Administration built complex simulations and leveraged hefty analytical capacity to help them model scenarios in which solar power from the desert Southwest helps to meet peak electricity demand in the Northeast and then supports similar demand peaks a few hours later in the West.

Likewise, abundant fossil generation resources in the East could find broader markets across the mid-continent seam in the West.