AgroÉnergie

Alternative Harvesting methods

The choice of harvesting equipment is governed by the size of the annual harvest area and by the biomass end use. Direct chip harvesting is the most common method used  today due to its high productivity and the commercial maturity of the underlying technology.

Equipments used in corn silage harvesting are adapted for willow. Pull-type silage harvesters enable the economical harvest of willow in small-scale biomass projects (< 50 hectares), while a self-propelled harvester with a specialized head will be required for larger annual harvest areas. The widespread use of these equipments opens the possibilities for contract harvesting by local operators. Willow harvest occurs during the dormancy period (november to april), a time when these equipments are available for use.

Pull-type silage harvester

Self-propelled forage harvester
(source : SUNY-Esf)

Billet harvesting constitutes an alternative harvesting method adapted from the sugar cane billet harvester technology. Although less productive than direct chip harvesting, harvesting willow in the form of billets reduce fiber exposure to rain and snow, which allows for unlimited outdoor storage without significant dry matter loss due to fermentation. The billet’s shape and size (15 à 20 cm in length) also allows for air flow through the pile, enabling a natural reduction of the biomass moisture content to a 20-25% level within a window of 4 to 6 months after harvest. Pioneered in the United Kingdom, the billet harvesting method is commonly used for the co-firing of coal with willow fuelwood in the country’s thermal power plant.

The Billet Harvesting Method

Billets

Round bale harvesting constitute another SRWC harvesting method allowing a natural drying of the biomass in outdoor piles. Manufactured in Canada by Anderson group, the  biobaler is a versatile technology which enables a biomass harvest in dedicated crops as well as in heterogeneous fallow land.