Here’s a multifaceted approach to using forest residuals or pros and cons of two approaches to using forest residues.
The first article (from the Wood Science Department UBC) describes relatively small production facilities in three communities with existing lumber mills.
The authors, Claudia Cambero and Dr. Taraneh Sowlati, describe an optimization model (mixed integer linear programming MILP model) which could use forest biomass shared between three communities with existing lumber processing facilities. The mills in Anahim Lake, Hanceville and Williams Lake could use relatively small processing facilities which would use harvesting residues and mill wastes to run a combination of systems to generate electricity, heat, gasifiers, pyrolysis and wood pellets.
A flow chart shows how the materials could move between the three locations to generate a variety of products including electricity which is now produced by diesel generators in the two remote locations.
The facilities would be relatively small (from 0.5 to 5 megawatt electrical generators) and 200 to 400 oven dry tons of wood waste for the pyrolysis plants.
The advantages from this approach are the creation of local jobs as well as the utilization of biomass that would normally be burned as waste because of the long distance from manufacturing plants.
There is not much detail in this one page report but the authors do claim a net present value of $565 million dollars over a 20-year period and most of the facilities could be operating in one year.
Another approach could be one described by Tony Kryzanowski in the February, 2015, Logging and Sawmilling Journal. A privately owned producer of bio-oil since 1989 (Ensyn Corp.) uses 70 bone dry tons of wood fibre daily for an annual production of three million gallons of liquid fuel per year.
The plant in Renfrew Ontario has developed a patented rapid thermal process that converts solid biomass to “liquid wood” in less than two seconds.
Other carbon by products are used in the heating process and the process yields about 70 percent of (renewable fuel oil, RFO) from the dry feedstocks.
Large facilities like hospitals use the RFO for their primary heating source. The RFO can also be sent to the refining facilities to be converted into gasoline or diesel fuel.
These two scenarios are good examples of a wide range of options from relatively small local investments to much larger high end facilities.
The smaller production units are not likely to be as efficient but they can be in operation much quicker, are likely more portable and could be paid off sooner. These two approaches could also be built with green house production facilities included in the planning process which is something the local food cooperative was considering with the existing cogeneration plant.
Unfortunately it’s operation may be in question with the uncertainty of the mid term timber supply recently discussed in the Chief Foresters AAC report on the Williams Lake TSA.
Jim Hilton is a professional agrologist and forester who has lived and worked in the Cariboo Chilcotin for the past 40 years. Now retired, Hilton still volunteers his skills with local community forests organizations.