Pelletization is the process of densifying wood into pellet form to be used as fuel. It is growing in popularity in Sweden, Germany, and the United States. This quality of the final product is sensitive on the moisture content, ash content and density of the pellet (DIN 51731 in Germany, and SS 18 71 20 in Sweden), but a quality pellet is a good alternative renewable heat source (1).
In pelletization, the wood shavings are fed into a pellet mill containing a roller die assembly. The die is rotated and spins the rollers which compress the feed to pellet density. We visited the Swedish Agricultural University’s pelletization research site and saw the technology used there. They were planning on testing pellets made with different ratios of woods.
Pelletization is prevalent in Sweden due to the abundance of pine, spruce, and birch trees. Sweden’s forestry industry is quite developed and we visited several plants that relied on trees as a feedstock. Smurfit Kappa is an efficient renewable power plant in Pitea, Sweden that produces wood pellets from the waste not fit for paper manufacturing. One problem faced with using pellets as a fuel is shortages during winter when the demand is high. Smurfit Kappa makes most of its pellets during the summer which allows it to operate almost year round.
The outlook for pellets is good for cold, forested regions. Sweden is expected to consume 2.65 million tons of pellets in 2012 (2) and Germany’s German Market Incentive Programme subsidizes the use of renewable heat sources including pellets (3). The United States has the resources for a large pellet industry.
- “Quality Standards for Pellets in European Countries.” European Pellet Centre. Web. 08 June 2012. <http://www.pelletcentre.info/cms/site.aspx?p=2550>.
- Hansen, Morten T. Pellets @las Country Report Sweden. Publication. 2009. Print.
- Hiegl, Wolfgang, and Rainer Janssen. Pellets @las Country Report Germany. Publication. 2009. Print.