Woodlot Feasibility for Biomass Facility at Colby College


Theo Papademetriou (’11)

ES212, Environmental Studies Program, Colby College




This project analyzes woodlot feasibility in providing fuel for the biomass facility being built at Colby College in the spring of 2012.  The demand for fuel is estimated at 22,000 tons of wood chips annually, fluctuating monthly due to consumption needs.  This project identifies the most feasible woodlots for supplying Colby College based on size and distance from the plant.  Categorized, the ranking of woodlots may be applied to decisions about where to get fuel as demand rises.  Minimum and maximum thresholds can be derived and scaled based on demand. 



In a campaign to become carbon neutral, Colby College is building a biomass burning plant to replace heating oil in the production of heat and electricity for the campus.  The plant will supply the campus with 90% of the steam for heat, hot water, and cooking, as well as produce 10% of Colby’s electrical need.  The plant is due to complete construction in the spring of 2012, and fuel sources are a major issue surrounding the neutrality of the project.  The college anticipates its sources to be within a 50 mile radius of campus as the crow flies.  This project analyses these woodlots based on their size (extrapolated into greater potential to supply fuel) and distance from Colby (≤50 mile radius).



Woodlots are derived from a 2007 survey from the Maine Office of GIS.  I used ArcGIS to analyze the data based on size and distance from Colby in order to classify the most suitable lots as fuel sources.  Size was determined by calculating the area of individual polygons of woodlots.  Distance is based on a Euclidean distance calculation and is categorized into concentric circles centered on Colby College campus.  It is therefore possible to index woodlots within certain distances from Colby against their relative size and derive the most and least desirable woodlots to supply Colby College with their demand for biomass fuel.  The categories for a woodlot’s viability can be adjusted based on the fluctuations in demand over the various months of the year; as demand changes sources will either expand out from or recede in towards Colby College campus.  This will allow Colby to reduce their carbon neutrality even more by diminishing emissions from transportation of fuel; the closer the source of fuel the more cost-effective the delivery (on emissions as well as economic terms).  This trend is displayed in Figure 1. 






Figure 1



Table 1


Woodlot Count (sum)

Woodlot Area (acres)

Mean Woodlot Size (acres)





Fall and Spring-25mi










Woodlots were broken down into three buffered zones; 10-, 25-, and 50-mile buffers.  Within the 10-mile buffer, there are 11 woodlots with a total area of 698,766 acres and a mean size of 63,524 acres.  Within the 25-mile buffer, there are 126 woodlots with a total area of 2,591,026 acres and a mean size of 20,563 acres.  Within the 50-mile buffer there are 502 woodlots with a total area of 24,972,434 acres and a mean size of 49,745 acres.  At roughly 37 green tons/acre (Forest Guild, 2010), and an annual use of no more than 20 percent of any woodlot’s land, this yields healthy supplies of biomass available for the Colby plant.




This study includes all woodlots currently available without discrimination.  Colby College may have specific circumstances or criteria for the sites chosen other than ease of delivery (as defined under this study as a function of size and distance from campus).  Expansions upon this will include classification and application of these criteria.  Some of the problems I ran into were the arbitrary weighting of the factors of distance and size during the indexing of the woodlots and the independent Euclidean distance calculation (preference would have been a least-cost path along roads).   




Woodlots are abundant in the state of Maine, and Colby has a number of options for the supply of biomass used in the plant.  Fluctuations in demand for fuel can be extrapolated from this project based on the categorizing of the woodlots; as demand increases during winter supply may come from more or further woodlots and fewer or closer woodlots during the summer.  Within the buffers, seasonal application and demand may be met, and the likelihood of needing to travel 50-miles away in order to obtain sufficient fuels is unlikely.




(MEGIS town boundaries, Colby College, woodlot ownership)

(ESRI roads)


Manomet Center for Conservation Sciences. 2010. Massachusetts Biomass Sustainability and Carbon Policy Study: Report to the Commonwealth of Massachusetts Department of Energy Resources. Walker, T. (Ed.). Contributors: Cardellichio, P., Colnes, A., Gunn, J., Kittler, B., Perschel, R., Recchia, C., Saah, D., and Walker, T. Natural Capital Initiative Report NCI-2010-03. Brunswick, Maine.


Perschel, Bob, Alexander Evans, and Mike DeBonis. Forest Biomass Retention and Harvesting Guidelines for the Northeast. Publication. Santa Fe, NM: Forest Guild, 2010. Print.



I would like to personally thank Philip Nyhus and Manny Gimmond for their assistance and support throughout the project and course.