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Developer combines coal and wind -- Part of grid solution

Two combined wind and clean coal projects proposed for the US Midwest could eventually help solve transmission problems now preventing wind power from reaching population centres to the west and the east. By allowing 50 MW of wind generation to ride on the back of a planned 1000 MW of coal plant, the plan is to spread the cost of the needed new transmission while also providing a partial green power option to customers.

The proposal has come from Great Northern Power Development LP and the Kiewit Mining Group. They are planning to build two 500 MW coal generating plants which will use circulating fluidised bed technology, one in eastern Montana and the other in western North Dakota, and combine them with the wind power.

Although both areas are rich in coal and wind, they lack the transmission infrastructure needed to get the energy to market. For this reason the combined projects will not be built until at least 2008. Jerry Vaninetti, president of Great Northern, says the economic justification for upgrading old and building new transmission lines works better when the baseload facilities come online at the same time as the wind generator, which is intermittent. The coal projects take three-and-a-half years to complete. With financing in place by late 2004, the developers could break ground by early 2005, he says.

Each coal plant will include two 250 MW generators, but the full rated capacity of the combined coal and wind project will stay at 500 MW because his company intends to curtail coal generation by up to 50 MW while the wind is blowing. To make this work, he says several details need to be worked out: how far in the future can the wind resource be predicted and how quickly can the coal operations be curtailed? "On that basis, we'll be able to offer a non-interruptible product," Vaninetti says.

bottlenecks

For the Montana project, located near Miles City, Great Northern is looking for power purchase agreements with Montana electricity retailers as well as companies in the Pacific Northwest. That transmission path is currently so congested that the Bonneville Power Administration (BPA) backed out of the 66 MW Blackfeet wind project in eastern Montana in May 2002 after realising transmission bottlenecks would prevent the federal power marketer from delivering the energy to Northwest markets (Windpower Monthly, June 2002). BPA, however, is working on one major transmission infrastructure project now and has dedicated hefty dollars to several smaller transmission projects it will complete over the next few years, all designed to remove the bottleneck from Montana.

Vaninetti says Great Northern will also look east towards Minnesota from its North Dakota project for similar improvements from the Western Area Power Authority (WAPA), a federal transmission authority. He says that while smaller upgrades may be needed to get the power to Sioux Falls, South Dakota, a major transmission project would still be needed from there to reach the population centres of Minnesota.

The cost of the transmission interconnection and whatever share of transmission improvements the developer would have to pay could add $100-$200 million to the two projects, says Vaninetti. He expects each project to cost about $900 million, a high price due to the clean coal technology. Of that $900 million, the 50 MW of wind generation is expected to cost about $50 million and developing the existing coal field at each site will cost about $70 million.

Great Northern's holding company, Great Northern Properties LP, is the nation's largest private holder of coal lands. Kiewit Mining Group owns and operates coal and lignite mines in the US.

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