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HomeMy WebLinkAboutThorne Bay Biomass Boiler Case Study - REF Grant 2195469 est 2000Thorne Bay, Alaska Thorne Bay School Wood-Fired Boiler Quick Facts Total Project Costs: $516,686.12 Funding: Renewable Energy Fund: $414,686.12 Local Funds: $102,000 Capital Costs Design: $19,360 Construction: $553,300 Equipment Make/Model: Garn WHS 2000 Output: 850,000 Btu/hr Diesel Fuel Offset Estimated Annual: 17,500 gallons Actual Annual: 7,500 gallons 2012-2014: 15,000 Fuel Savings Estimated Annual: $39,450 Actual Annual: $18,000 2012-2014: $36,000 Estimated Payback: 5.58 years Actual Payback: 28.7 years CASE STUDY Project Overview Th e Th orne Bay project involved placing two GARN wood-fi red boilers adjacent to Th orne Bay school and running underground piping from the boilers into the school’s heating system. Rather than use pellets or chips for fuel, Th orne Bay uses cordwood that is chopped by community members. Chopping the wood creates local jobs; in part because of this, money continues to stay in the community. Objectives Th e main objectives of this project were to design and construct a wood fi red boiler system that would provide heat to Th orne Bay School. Using this system displaces expensive diesel fuel, reduces their energy costs, and reduces diesel atmospheric emissions. Relevant Information Th e GARN PAK WHS 2000 is a “boiler room in a box” that is factory built inside a pre-insulated build- ing. Upon delivery, all that was required was to con- nect the piping and electrical on site. Th e wood fi red boilers were integrated into the current diesel heating system through a series of underground pipes, pumps, and heat exchangers that transfer energy in the form of heat. GARN wood heating systems can burn cord wood, slab wood, pallets and other scrap wood, dense wood briquettes, and air-dried corn on the cob. GARN hydronic heaters produce virtually no smoke because of their patented two-stage wood gasifi cation technology. Economic Feasibility Th e system became operational in January 2013 and has since provided 1,633 MMBtu of thermal energy and displaced 15,000 gallons of diesel fuel, saving Th orne Bay School $36,000. Over its 20 year life span, the project has a calculated benefi t/cost ratio of 3.18, Garn WHS 2000. Photo courtesy of Dan Bihn. meaning that the benefi ts outweigh the costs by 3.18. Fuel and Storage Th e school is located in the heart of the Tongass Na- tional forest, the largest forest in the nation. Due great- ly to this, there is more than enough wood to supply the school’s needs. Wood is supplied by local sawmills, USFS small sales, and from small local fi rewood cut- ters. Once the cordwood is purchased, local residents are paid to chop it (ensuring local involvement) before it is stored in a warehouse. Wood can be stored for up to a year or more ahead of time, ensuring a reliable and reasonable source of energy. When the wood is dry enough, it is placed in the boiler for heating. Learning Experiences/Challenges Th ey’ve had lots of challenges, said Jonathan Fitzpat- rick who leads the program. Th ey’ve had to focus on stabilizing the greenhouse’s pH and electrical conduc- tivity. Th ey’ve dealt with leaks. Th ey’ve done electrical troubleshooting to keep the system running. During the winter, the greenhouse and the school are heated by a wood-fi red boiler, which is stoked each hour. Be- cause of these trials, however, other communities now have a resource on which to call should they experi- ence any similar issues. Community Benefi ts 1. Students of Th orne Bay School care for a greenhouse that supplies the school lunch program with regular greens for its salad bar; soon, they’ll supply the whole school district and nearby businesses with about 250 heads of lettuce a week. 2. Plumbing the school for a supplemental wood fi red boiler provided additional jobs in the community. In addition to this, money that has previously left town in the form of payments to a diesel fuel provider, are invested locally. Project Contact Information Parties Involved: Jonathan Fitzpatrick, Email: jfi tzpatrick@sisd.org Lauren Burch, Superintendent Email: lburch@sisd.org Phone: 907-828-8254 Case Study Author: Zoe Tressel, AEA Email: ztressel@aidea.org Phone: 907-771-3000 Boiler storage facility, Photo courtesy of Jonathan Fitzpatrick Student-built wood crates, Photo courtesy of Dan Bihn. Greenhouse vegetables, Photo courtesy of Dan Bihn.