From Forests to Energy: The Economic Challenges and Benefits of Producing Bioenergy

Wood Pellets - Credit CERTS
Wood Pellets – Credit CERTS

E-04: Forest Biomass Supply Chains: Domestic Fuelwood and Biomass Heating

There are many commonalities in bioenergy supply chains around the world as countries attempt to harvest, collect, and process woody biomass from forests for power. According to the majority of the speakers in this technical session, one of the most resounding challenges is the cost of transportation. These costs can make up to 40 percent of the expenditures associated with biomass harvesting, according to Dr. Rene Zamora-Cristales from Oregon State University.

Half of the speakers in this session addressed the coal industry’s move towards integrating bioenergy from woody biomass into coal-fired energy production. Economist Alexander Moiseyev mentioned how this is especially appealing in countries in Europe and in the United Kingdom, where subsidies are offered to companies that incorporate bioenergy into their coal power plant infrastructure. Subsidies and feed-in tariffs (FIT) are financial incentives to use wood residuals for power co-generation.

However, many factors influence the economic feasibility of acquiring the woody biomass which prevent its use in co-firing power generation from becoming more commonplace in the coal industry. Some of the factors are specifically associated with the proximity of biomass to the power plant, the availability of the feedstock, and the consistency of the feedstock supply. These factors essentially guide the overall cost of transportation.                                       

Kazushiro Aruga from Japan explained the FIT application in the city of Sano in the Tochigo prefecture. There, the Nakagawa sawmill, owned by Tohsen Co. Ltd., provides wood power for the mill’s lumber kilns, chip boilers, as well as a mango greenhouse. It also supplies the biomass used to co-power the local coal plant’s 25MW power generator. However, due to the lack of accessibility to the biomass, more incentives are likely needed to build added road infrastructure to enable future harvesting of the biomass.

Compared to sourcing biomass from smaller trees, Dr. Michael Goernt from the University of Missouri found that the use of logging residues in the southeastern United States is likely the most economical source of biomass; however, this depends widely on the area’s harvesting rates.

In addition to logging rates, Dr. Rene Zamora-Cristales, who looked at the accessibility of biomass on steep terrain, mentioned many setbacks associated with collecting the woody materials that would otherwise be burned on-site. One of the challenges addressed was the need to increase the bulk density of the woody materials collected for power generation. This woody waste consists mainly of limbs and tree tops that remain after the logs are processed during the harvesting stage. This wood “waste” is otherwise burned in slash piles, which some consider an impractical practice, but, in fact, it is quite common in the forest industry.

Due to the topography in the northwest United States, transport costs accrued are not only based on transport fuel and distance from mills, but also the time it takes to transport the goods. For areas with steep terrain, trucks are driven slower and, in general, road infrastructure can be quite challenging for large trucks and trailers to haul the woody slash. These logistical challenges put a strain on the economical feasibility of removing this woody slash for power production.

Whether the wood waste is being chipped or grinded, when the material is placed in the trailer to be hauled out of the block, the bulk density is not very high because of the irregular shape and size of the wood pieces. Even shaking the trailer could mitigate this problem, although it might be somewhat laughable to consider this as an option. An alternative would be to use larger trailers, but again the roads may not accommodate this.

Thomas Buchholz’s research on the use of short-rotation crops in bioenergy production in Sub-Saharan Africa touched on some inherent principles that apply to bioenergy production in general. While wood power has been proven to be a reliable source of energy, it is typically not used by itself, and instead is combined with another source of energy production.

When considering the common economic difficulties of accessing wood residuals for bioenergy, it is hard to predict the security and consistency of woody feedstock in some countries. For now, the use of wood residuals and short-rotation crops, as well as government subsidies and FITs, are facilitating the integration of bioenergy into fossil fuel-derived energy. And this is at least one big step in the right direction.

 

Written by: Nichola Gilbert

 

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