Wednesday, September 07, 2016

The Birth and Troubled Childhood of an American Supergrid

The world of electricity transmission initially moved in Tesla's [AC] direction, but in 1954 a persistent Swedish engineer, Uno Lamm, proved he had solved Edison's [distance] problem by sending DC power from Sweden's electric grid through an undersea cable to the island of Gotland, 60 miles away in the Baltic Sea.  He had invented new controls that made DC electricity lines far more capable of moving electricity over long distances than AC could.

It was a bold accomplishment, and in 1961, the Kennedy administration approved a much more ambitious DC project called the Pacific DC Intertie, an above-ground power line that could move electricity from hydroelectric dams in the state of Washington to markets in Southern California.  Private power plant owners in California lined up against the line.  Then ASEA, the company that Lamm worked for, sent him to the United States where he convinced experts that importing cleaner DC power would save California's consumers $600,000 a day when the line was completed in 1970, which it did.

DC power lines also have other ways of selling themselves.  ABB, the Swedish-Swiss multinational engineering firm, which later took over ASEA, built a DC power line in the 1990s carrying hydroelectric power from Quebec to Montreal and into New England.  On Aug. 14, 2003, the more sophisticated and muscular controls on this line stopped the massive blackout in the northeastern United States from cascading into Canada and then helped the U.S. power grid restore power more quickly.
Under the TransWest Express LLC proposal, energy would be delivered from south-central Wyoming to California, with a hub in Nevada and a potential future terminal near Delta, Utah.  (Image Creit:  TransWest Express) Click to Enlarge.
[O]ther companies ... have since jumped in with proposed for-profit HVDC lines, which are called "merchant lines" in the business.  Some of them, like TransWest, are aimed at bringing renewable energy from Great Plains states to California and the Southwest.  Others, such as Houston-based Clean Line Energy Partners, are more interested in moving cheap and abundant wind power from Plains states to markets hungry for renewables in the East.
'Two different paths' to a cleaner future
The growing stream of U.S. long-distance proposals has also attracted companies with long experience in building and operating HVDC, the main one being National Grid, the U.S. subsidiary of the company that operates the systems that market gas and electricity across Great Britain.

Located in Waltham, Mass., National Grid has invested $40 million in Clean Line's projects, as well as launching two of its own.  One, Maine Green Line, would distribute a mix of wind-generated power from Maine and hydroelectric power from Canada.  Another, Vermont Green Line, would originate in northern New York and feed wind and hydroelectric power mainly from an underground and underwater line through Vermont.

Stan Blazewicz, vice president of U.S. business development for National Grid, explains that as two aged nuclear power plants are shutting down in New England, the demand for low-cost clean energy is soaring.  Most states in the region have set targets for 80 percent renewable power by 2050.
Exactly what policy the U.S. government will adopt toward the surge of interest in merchant-driven HVDC lines remains unclear.  There are two studies that show possible futures.  One, released in 2012 by the U.S. Department of Energy, included participation from industry and university experts.  It calls for more HVDC lines and interconnections to help promote long-distance flows of wind power throughout the nation.  It also calls for large batteries and other forms of storage to eliminate the variability of wind and solar power that can impede transmission.

Another study, released in January by a team of weather and grid experts formed by the National Oceanic and Atmospheric Administration, proposes a "Super Grid," a 30,000-mile nationwide network of underground HVDC lines that can create a national market for excess wind and solar power by quickly distributing renewable energy to places anywhere in the United States that need it.  In theory this grid would eliminate the need for storage.

Both studies aim at 80 percent reduction of emissions from the nation's electricity system by 2050 — which would provide substantial help to efforts to mitigate climate change — however, they differ on costs and the mix of transmission systems that will be needed to reach the target.

Read more at The Birth and Troubled Childhood of an American Supergrid

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