Accomplishments
Since its inception, the Chariton Valley Biomass Project (CVBP) has completed a wide range of valuable research studies and achieved a number of significant technical successes. The following list provides a brief summery of some of these activities to date and provides links to more detailed information:
- At its core, the CVBP is aimed at generating economic and environmental benefits on the region’s farms. The project team, led by efforts from researchers from Iowa State University and the University of Iowa, has completed studies in the following areas: fertility and yield trials, soil stabilization and soil quality, water quality impacts, carbon sequestration, avian and wildlife impacts, intercropping systems, yield optimization, cool season grass trials, disease and weed control, switchgrass production economics, switchgrass gasification research and analysis, determining chemical characteristics for switchgrass and cool season grasses in the project region, life-cycle greenhouse gas emissions, and valuation of societal benefits from the project. These studies have helped to quantify the potential benefits and impacts of the project and have helped to establish valuable management guidelines for project partners. For detailed results from these studies, click here.
- From November 2000 through January 2001, project partners completed the project’s First Cofire Test at Ottumwa Generating Station.
- During 2002, project partners developed the following planning documents: Draft Fuel Supply Plan, Equipment/Facility Design Package, Environmental Permits Plan, Draft Sales Contract Report, and Environmental Strategies Plan. These documents and the efforts that led to their creation set the stage for some of the project’s successful work during the following years.
- During the Spring of 2003, the project team presented a thorough review of the full range of economic aspects of the project, demonstrating the conditions under which the project would be able to operate as a commercially viable business after the government cost-shared research and demonstration phase of the project was completed. A panel of independent expert peer reviewers selected by the U.S. Department of Energy provided a favorable review of the project and the information presented at the meeting.
- From November through December 2003, project partners completed the project’s Interim Cofire Test at Ottumwa Generating Station.
- In September 2004, Interstate Power & Light (a subsidiary of Alliant Energy, and operating company for Ottumwa Generating Station) and Prairie Lands Biomass, LLC signed an agreement for the supply of switchgrass as fuel for Ottumwa Generating Station, pending future co-fire test results and several other conditions.
- During Spring of 2005, Alliant Energy / Interstate Power & Light and Chariton Valley RC&D Inc. received approvals and permits necessary for operating the Chariton Valley Biomass Project on a commercial basis at a switchgrass input rate up to 25 tons per hour (the equivalent of 35 megawatts of electricity generation). This permission was granted by the Iowa Department of Natural Resources and the U.S. Environmental Protection Agency.
- Construction of a new, permanent switchgrass processing facility began in late Spring of 2005. This new facility will be used during the project’s Long-Term Test Burn and could be used for commercial operations once the government cost-shared research and demonstration phase of the project is completed. For updated construction photos, click here.
- During June 2005, project partners presented the results of the fly ash testing program from the project’s Interim Test Burn. Based on the results of the thorough testing program, Alliant Energy received formal approval from the Iowa Department of Transportation in July 2005 to sell fly ash from switchgrass cofiring operations at Ottumwa Generating Station for concrete applications. Under the approval conditions, switchgrass can represent up to 5 percent of the total heat input at the power plant.
First Cofire Test
After several years of planning, the Chariton Valley Biomass Project successfully completed two months of switchgrass co-fire testing at the Ottumwa Generating Station (OGS) in Chillicothe, Iowa. From November 30, 2000, through January 25, 2001, the switchgrass team co-fired 1,269 tons of switchgrass at rates up to 16.8 tons/hour, representing about 3% heat input to the 725 MW power plant. Stack testing was completed when co-firing switchgrass and when burning only coal. Fuel and ash samples were collected for analysis and boiler performance and emissions data was collected. Numerous improvements were made to the feed-handling equipment during testing and the testing was completed with no environmental incidents, no injuries to personnel, and no loss in electricity output from OGS.
The goals of this test—the first of three rounds of co-fire tests—were: to identify the effects of co-firing on boiler performance, to measure any changes in emissions during co-firing, and to gather information to improve the design of the switchgrass handling equipment. All three of these goals were met. The design target for the switchgrass handling system was 12.5 ton/day, which was exceeded after a redesign of the secondary grinder in our system. During several days in January, the project team burned more than 100 tons of switchgrass. For a complete report on the First Cofire Test results, click here.
Interim Cofire Test Burn
The interim cofire test, the second round of co-fire testing, was conducted during the first two weeks of December 2003. Pre-testing of biomass processing equipment and sampling techniques occurred between November 21 and 26, 2003. This test was performed using an improved switchgrass handling system and was done to verify air emissions, obtain large samples of co-fired fly ash for testing, and further analyze the technical feasibility of switchgrass co-firing at OGS. To meet the objectives of the Interim Test Burn, it was only necessary to burn an estimated total of 781 tons (1,673 bales) of switchgrass during the pre-test and testing periods combined. The average switchgrass feed rate during the December cofire testing was about 8.9 tons per hour, representing about 1.9 percent of the boiler’s heat input.
The interim test burn was successful in showing measurable decreases in sulfur dioxide emissions and no significant change to the carbon monoxide, particulate, and nitrogen oxide emissions while co-firing. Subsequent concrete testing using the co-fired fly ash by Iowa State University has shown the concrete with the co-fired fly ash can meet the ASTM requirements as concrete with the coal fly ash.
Long Term Test Burn
The long term test burn was a 3-month test burn of switchgrass with coal at the Ottumwa Generating Station in Chillicothe, Iowa. By the end of the test burn on Friday May 12, 2006, the Chariton Valley Biomass Project team, had accomplished the following during the 3-month test burn:
• Delivered, processed, and burned 31,568 bales of locally grown switchgrass totaling 15,647 tons as renewable fuel for generating electricity at Ottumwa Generating Station (OGS).
• Generated 19,607,000 kilowatt-hours of electricity from the renewable switchgrass fuel. That is enough electricity to provide 100% of the electricity needs for an entire year for over 1,874 average Iowa homes. This is a world record for electricity generation from switchgrass.
• Processed and burned switchgrass as fuel at OGS for more than 1,675 hours since mid-February, 2006. Processing hours per day have improved significantly since the beginning of the test burn, with the facility operating without downtime nearly continuously throughout the past month of the test burn.
• Reduced emissions of sulfur dioxide (SO2) from OGS by about 62 tons due to the extremely low sulfur content in switchgrass. The coal used as fuel at OGS is low-sulfur coal, but not as low in sulfur as the switchgrass which contains only about 0.1% sulfur (by weight).
• Reduced emissions of carbon dioxide (CO2), the primary greenhouse gas, by a total estimated amount over 50,800 tons through reductions at the power plant, and because the switchgrass absorbs carbon dioxide from the air during its growth cycle and stores a portion of the absorbed carbon in its deep root system—this also improves the soil conditions on the fields where the switchgrass is grown.
• Generated about 626 tons of fly ash which has been approved for sale from the power plant for use in concrete and other valuable byproducts. The ash is what is left over from the switchgrass after it is burned in the boiler. This ash is collected at the power plant along with ash produced from the coal.
• Demonstrated that the processing system designed, installed, and operated by the project team throughout the test burn can be operated reliably at and above its designed process rate of 12.5 tons per hour, especially if the switchgrass delivered to the facility contains moisture contents of 12% and under. The average moisture content of switchgrass burned throughout the test burn has been about 13%.
• Replaced about 12,060 tons of coal purchased from Wyoming with renewable switchgrass that was planted, grown, harvested, stored, delivered, and processed by local Iowa farmers.
• Generated an estimated 19,600 Renewable Energy Credits (RECs) that have received independent third-party certification under Environmental Resource Trust’s EcoPower program. This program certifies the amount of power generated during the test burn that resulted from a renewable energy source, and allows the project team to market the RECs to companies, government organizations, and/or residential consumers who are willing to pay a small premium to ensure that a portion of their energy purchases go to a renewable power generator. Purchasing these RECs can help companies and government organizations meet their environmental goals.
For more background information on the project, please see the following links: