Biomass resources in Alaska are extensive and diverse, comprising millions of acres of standing small-diameter trees, diseased or dead trees, and trees having lowgrade timber. Limited amounts of logging and mill residues, urban wood residues, and waste products are also available. Recent wildfires in interior Alaska have left substantial volumes of burned timber, potentially usable for biomass energy. Motivated, in part, by rising fuel prices, organizations across the state -- including businesses, schools, and government agencies -- have all expressed an interest in wood energy applications. Numerous sites have pursued feasibility studies or engineering design analysis, and others have moved forward with project construction. Recent advances in biomass utilization in Alaska have been enabled by numerous factors, and involve various fuel sources, scales of operation, and end products. Already, thermal wood energy systems are using sawmill residues to heat lumber dry kilns, and a public school heating system is in operation. Management policies on national forests and state forests in Alaska could determine the type and amounts of available biomass from managed forests, from wildland-urban interface regions, and from salvage timber operations. Biomass products in Alaska having potential for development are as diverse as wood pellets, cordwood (firewood), compost, wood-plastic composite products, and liquid fuels. In addition, new technologies are allowing for more efficient use of biomass resources for heating and electrical generation at scales appropriate for community power. This case study review considers successes and lessons learned from current wood energy systems in Alaska, and also considers opportunities for future bioenergy development.

The inadequate transportation infrastructure and undeveloped markets for sawmill residues in southeast Alaska are among the factors that limit the use of this forest resource. This study considers the potential use of sawmill residues to supply two bioenergy systems that would produce thermal energy for (1) community heating and (2) a lumber dry kiln in Hoonah, Alaska. The proposed community heating system would be a direct combustion system, burning approximately 1,450 green tons (1.315 green metric kilotons) of wood fuel per year to provide heating for seven centrally located buildings in Hoonah. Additional sawmill residues would be used in another system to provide process heat for a proposed 25,000 board foot (41.3 m3) dry kiln. The Hoonah sawmill typically produces as much as 5 million board feet (8,255 m3) of lumber per year, primarily from western hemlock and Sitka spruce. The processing of this amount of lumber would result in an adequate volume of residue to provide a fuel source for the heating requirements of the proposed projects. Wood residue from the sawmill is assumed to be available at no cost other than for transportation. Use of wood fuel for community heating would save an estimated 65,000 gallons (2.47 kL) of heating oil per year. Avoided fuel costs would be approximately $91,500 per year based on No. 2 fuel oil at a market price of $1.40 per gallon ($0.37 per liter). Based on a project life of 25 years and a contingency rate of 25%, the expected after-tax internal rate of return (IRR) for the community heating portion of the project is 29.6%. Total installed costs for the 1,195,000 Btu/h (350 kWthermal) community heating system, including distribution piping and its installation and backup oil systems, are estimated to be $631,000. For the lumber dry kiln, in the second heat-generating system, economic results were less favorable, with expected energy savings of $82,900 per year and an after-tax IRR of 24.1% (also assuming 25% contingency). Estimated installed cost of the 1,536,000 Btu/h (450 kWthermal) dry kiln system with a backup oil system is $513,800.

Wood has become an important energy alternative in Alaska, particularly in rural areas where liquid fuel costs can be substantial. In some cases, wood fuel is readily available to communities, increasing the attractiveness of wood energy. Wood energy systems in rural Alaska can also lead to employment gains as well as benefits to local cash economies. Many Alaska villages are now considering wood as a fuel source for community heating, several have completed feasibility studies, and others are moving forward with design and construction activities. Cordwood is readily available in many regions of Alaska, although not always in commercial quantities. However, for many small-scale applications, efficient cordwood systems could be a viable energy option. In this paper, we provide a qualitative review of factors such as wood fuel availability, cordwood system size, wood fuel cost, wood quality, labor, fuel drying, and underground piping. Other general observations are noted, based on case studies of operating cordwood systems in Alaska.

This report is concerned with the existing volumes of renewable wood energy products (RWEP) currently used in Alaska and the potential demand for RWEP for residential and community heating projects in the state. By using peak prices from the fall of 2008, the potential value of a British thermal unit (Btu) from various fuels has been calculated to identify those situations where wood-based fuels are economically competitive or advantageous when compared with alternative fuel sources. If fuel oil prices increase to the levels experienced in 2008, there would be a strong economic incentive to convert heating systems to use solid wood fuels. Charts and tables. This is a print on demand edition of an important, hard-to-find report.