Craig District Heating System Using Biomass (Wood Waste) to Supplement Oil and Propane at the Craig Aquatic Center, Craig Elementary School and Craig Middle School
Moving From Traditional Fuels to Wood Waste • Background • Making a decision to move to a biomass heating system • Identifying local needs and local resources • Putting the funding together • Getting the system up and running • Conclusion
Background • City of Craig owns and operates a full size pool, kiddie pool, and hot tub. The water and air were previously heated by propane. • The Craig City School District operates two school buildings adjacent to the pool site, both of which have conventional oil-fired, hydronic heating systems.
Making the decision to move to a biomass heating system • A 2004 report commissioned by the city recommended converting the pool from propane to diesel or wood heat. The report also recommended a detailed analysis of wood fired systems. • A subsequent, more detailed analysis of wood heat was prepared by TR Miles Technical Consultants at the direction of the Alaska Energy Authority.
Making the decision to move to a biomass heating system • The report prepared by TR Miles Consultants showed that a wood boiler was feasible with oil priced at $1.46 per gallon and propane priced at $1.72 per gallon. • In 2004 this equaled about $67,000 per year in propane costs at the pool, and $20,440 in heating oil costs at the schools. • Of course the prices didn’t stay there…
Making the decision to move to a biomass heating system • City and school district staff visited existing wood fired systems in Montana to gauge the merits of operating similar systems in SE Alaska.
Identifying local needs and local resources • The City of Craig had a number of primary concerns • Long term availability of fuel • Moisture content of wood fuel • Cost of operation • Noise, odor, and exhaust near schools and residential neighborhoods
Identifying local needs and local resources • Wood fired systems can use either cord wood or chips/hog fuel. • It was determined that chips and hog fuel were readily available and would work well in an automated system. • Local mills generate chips and hog fuel in amounts that far exceed the amount of fuel needed to meet the project scope.
Putting the funding together • Alaska Energy Authority • US Forest Service • Denali Commission • Natural Resource Conservation Service • City of Craig
Putting the funding together • Original engineer’s estimate was $900,000 • Final estimate and construction cost was $1.5 million. The city broke ground in 2006
Getting the system up and running • Construction of the building, including the fuel storage, drying and deliver system started in late 2006 and was completed in early 2008. • The two stage burning boiler was purchased as a unit. • Insulated hot water supply and return lines were run to the pool and school buildings.
Getting the system up and running • The boiler was delivered and put into the building in December 2007
Getting the system up and running • The system was fired up for the first time in April 2008
Closing Remarks • Biomass is a great alternative for much of Alaska • Develop partnerships to help with the process from feasibility to design to construction to operation • Focus on the challenges and opportunities that are unique for your community • Continue to look at how you can expand the usability of a central system