Cofiring Test Success

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During the Winter of 2003, project partners executed a one-month test burn of switchgrass with coal at Alliant Energy’s Ottumwa Generating Station (OGS) using a temporary switchgrass processing facility. The objectives of the test were to:

  1. Operate and optimize the prototype switchgrass processing system at full-scale (12.5 tons of switchgrass per hour),
  2. Collect detailed air emissions data to assist with air permitting,
  3. Collect and test ash samples from co-combustion of switchgrass with coal, and
  4. Evaluate other impacts on operations at the power plant.

All objectives of the test burn were achieved. Based on the test burn results and follow-up efforts, the following milestones have been accomplished:

  1. Air permits have been obtained to allow construction and operation of a new 25 ton per hour switchgrass processing facility at OGS,
  2. Construction of a new, permanent switchgrass processing facility at OGS commenced in the Spring of 2005,
  3. Fly ash from switchgrass and coal co-combustion was shown to be well-suited for use in concrete and official approval has been gratned by the Iowa Department of Transportation , and
  4. There were no measured negative impacts of the short-term test burn on the OGS power plant.

The project is now in the process of preparing for a 2,000 hour continuous test burn using a new switchgrass processing facility that, if the long-term test results are positive, could be operated on a commercial basis in the near future.