Big Muddy making big hydropower recovery

BISMARCK, N.D. -- Hydropower production is projected to make a big comeback on the Big Muddy.

Electric power generation by Missouri River dams is forecast to be above average in 2011 for the first time in a dozen years because of more mountain snowmelt and wetter weather, according to the U.S. Army Corps of Engineers, which manages dams and reservoirs along the 2,341-mile river.

Shallow river levels caused by nearly a decade of drought cut hydroelectric generation at the six dams in the Dakotas, Montana and Nebraska, forcing the U.S. Energy Department's Western Area Power Administration to spend more than $1.5 billion since 2000 buying power elsewhere to fulfill contracts, said Randy Wilkerson, a WAPA spokesman in Lakewood, Colo.

Wilkerson said the WAPA likely won't have to buy more electricity on the open market this year to make up for hydroelectric shortfalls.

"We expect to be back to normal," he said.

The Missouri River reservoirs began rebounding slightly in 2008 and strongly in 2009 because of rains and robust snow runoff, and are at ideal levels now, said Mike Swenson, a corps engineer in Omaha, Neb.

"The pools have really started recovering well," he said.

Most power since 1999

The Missouri River plants should generate 10.4 billion kilowatt-hours this year, the highest since 1999; the corps expects the plants to produce 10 billion kilowatt-hours "under normal reservoir levels and normal releases," Swenson said.

The plants have generated an average of 9.3 billion kilowatt-hours of electricity since 1967, including a high of 14.6 billion kilowatts in 1997, Swenson said.

In 2010, the plants generated 8.7 billion kilowatt-hours, up from 6.6 billion kilowatt-hours in 2009, he said. During the driest years in the past decade, power plant output shrunk below 5 billion kilowatt-hours in 2007 and 2008, Swenson said.

The water storage level of the six upstream reservoirs in the Missouri River system is nearly 57 million acre feet at present and equal to the ideal level, Swenson said. An acre foot is the amount of water covering an acre, one foot deep.

Oahe Dam near Pierre, S.D., which holds Lake Oahe in the Dakotas, and Garrison Dam, which creates Lake Sakakawea in western North Dakota, are typically the biggest power producers in the Missouri River system, Swenson said.

Oahe Dam generated 2.5 billion kilowatt-hours in last year, just below the long-term average of 2.6 billion kilowatt-hours, Swenson said. The dam recorded a low of 1.1 billion kilowatt hours in 2007.

Garrison Dam generated 2.1 billion kilowatt-hours of electricity last year, up from 1.5 billion in 2009 and a low of 1.3 billion in 2008, Swenson said. The long-term average at the dam is 2.2 billion kilowatt-hours.

The Bismarck-based Lignite Energy Council said an increase in hydroelectric production at Garrison Dam contributed to a 1 million ton cut in coal production last year in North Dakota.

The Western Area Power Administration, which buys and sells power from 55 hydropower plants around the nation, says the six Missouri River dams are WAPA's second-largest producer of energy.

WAPA had a 37.6 billion kilowatt-hour shortfall from electricity production from hydropower over the past decade, or nearly four years the amount of power the Missouri River dams would have produced under normal conditions, Wilkerson said.

"That's a nice way to put in perspective," Wilkerson said. "That's a lot of electricity."