Economic and environmental benefits of community-scale cordwood hydronic heaters in Alaska—three case studies

Over the past decade, the use of wood for thermal energy in Alaska has grown significantly. Since 2000, nearly 30 new thermal wood-energy installations in Alaska have been established. Cordwood units, burning primarily firewood and other forms of roundwood, have played an integral part in this success and are well suited to many rural communities in Alaska. In this case study, we evaluate cordwood installations located in three geographic regions of Alaska. Included are systems at Coffman Cove (southeast Alaska), Ionia (Kenai Peninsula, Alaska), and Gulkana (south-central Alaska). We considered the wood-energy conversion process, system operation, economics, and carbon benefits of the three cordwood systems. We found that the simple payback period ranged from 1.1 to 14.2 years and the internal rate of return from 8 to 91 percent, and that benefits exceeded costs by a factor of from 1.6 to 17. There were also substantial carbon benefits for cordwood systems. Carbon dioxide (CO2) emissions (relative to those from heating oil) differed by installation from 129 to 259 tons avoided per year, with total reductions of 611 tons of CO2 per year. We also considered secondary benefits of community-scale cordwood energy systems in rural Alaska, including greenhouses for local foods, the ability to create part-time jobs for local residents, and the educational experiences for school students.