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Concerning slash in our forests, the economics are largely site specific. As Professor Boston mentioned yesterday, the slope of the ground, road access, size and amount of biomass collected all have impacts on whether or not it is profitable to collect it for use in a facility like ours. The biomass fuel market is also important. A year ago biomass prices were about 40-50% higher than they are today, due to the fact that the economy is suffering, spot market electricity prices are lower, and overall consumption has decreased. At last year's prices it absolutely made sense to put more effort into collecting available slash, while today it makes less sense.

As for using slash for pellets, it's a trickier poposition. In order to make pellets the wood used has to be clean, small, and have less than a 6-8% moisture content. Typically, sawdust and shavings from lumber operations have supplied the majority of the material for pellet manufacture. Green wood from the forests can range between 30-70% moisture content on a wet basis (depending on the time of year and how long it has been sitting), which would mean that any material used for pellet manufacturing has to be dried in some fashion, which would also mean emissions from drying facilities. Our biomass boiler operates at a fuel moisture content range of 40-60%, which allows us to use green wood, and in wet months a portion of supply from ground pallets or construction debris helps to bring overall moisture content down to reasonable levels. Anything over about 65% MC, and it takes all of the energy from the wood just to get the water out of it.

A distinction has to be made between different types of biomass for different uses as well. We can't burn yard trimmings or leaves, since the MC is higher than is beneficial to burn. These products largely go into composting operations where they can be used in gardens or yards as a substitute for bark dust.

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To PeterMcDonald's comment concerning philbert fields. During summer months when the fields are accessible, agriculture biomass such as filbert trees, cherry trees, and christmas trees do come our way. For farmers that are doing crop rotations, receiving money for the biomass makes financial sense. Without a facility to send the material to, they would not be able to offset rotation expenses and would most likely be piling and burning the material for no economic or environmental benefit. This is much the same argument for collecting material that would have been piled and burned in our forests as part of slash mitigation efforts.

There was also a comment concerning the efficiency of boiler operations. The 74% efficiency factor of our biomass boiler is calculated by the BTU or energy recovery. So if there are theoretically 5,000 BTU's/lb of biomass delivery to the combustion chamber, we can capture 3,700 BTU's in our conversion to steam. There is much science that goes into increasing the efficiency of these systems, and it is in our best interest to get as much energy out of the biomass as we possibly can. Regardless of the technology you use, the possiblity of capturing 100% of the energy when converting from one form to another is not available.

Concerning emissions from biomass facilities, efficiency of combustion is of primary concern. Of course anytime wood is combusted there are pollutants in the airstream. This has to be weighed against the potential pollution from catastrophic fires such as the 2002 Biscuit fire which left a haze from southern Oregon up to Salem and had a substantial negative financial affect on Oregon. It also has to be weighed against other energy sources such as coal that have far more serious emissions than a biomass plant with a carbon-neutral footprint.

posted 3 years, 11 months ago
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