A study published by IVL Swedish Environmental Research Institute shows that in a lifecycle perspective the level of greenhouse gas emissions linked to pellets may differ widely. The fuel used in drying and transport and distances from factories to pellet users is particularly crucial. The study establishes that pellets produced in Sweden and in modern facilities in Latvia, Canada and Russia release lower levels of greenhouse gasses into the atmosphere.
– The study indicates that pellets produced in Sweden are mostly a climate-efficient biofuel. However, it was a surprising to discover that a number of pellet products generated significant carbon emissions that could be traced back to the production and transport chain, said Mathias Gustavsson, one of the researchers behind the study.
The life cycle studies show that greenhouse gas emissions vary between 2 and 25 grams of carbon dioxide equivalents per MJ of pellets. Compared to a system that uses fossil fuels, pellet plants emit between 64 and 98 per cent less carbon dioxide equivalents when used to generate electrical power, and 77-99 per cent less carbon dioxide equivalents when used in district heating centres.
The study is based on the methodology for the assessment of associated emissions for electricity and heat produced from solid biomass now under discussion in the EU. The EU does not propose to introduce sustainability criteria for solid biomass anytime in the near future. However, in Sweden electrical power companies are already required to specify emissions linked to the production of electricity. Furthermore, many district heating suppliers report emissions of greenhouse gases linked to the district heating products they offer.
– Based on the results of the study, there is every reason for players relying on pellets to produce electricity and heat to scrutinize the sources of the pellets they buy, and to make sure these come from efficient and modern production facilities, says Mathias Gustavsson.
The results of the study are presented in a scientific article published in Biofuels, Bioproducts and Biorefining (http://dx.doi.org/10.1002/bbb.1538), authored by IVL staffers Julia Hansson, Fredrik Martinsson and Mathias Gustavsson and entitled “Greenhouse gas performance of heat and electricity from wood pellet value chains – based on pellets for the English market.” The study was funded by a grant from the Swedish Energy Agency.
Facts about pellet market in Sweden Pellets are a processed wood fuel that over the last 15 years has played an increasingly important role in Swedish energy production. According to figures from the Swedish Pellet Association, in 2014 Swedish production of pellets exceeded 1.5 million tonnes, which is equivalent to an energy content of between 6.7 to 7.5 TWh. In the same year the use of pellets in Sweden totalled almost 1.8 million tonnes, most of which, or approximately two thirds, was used in larger installations such as power plants and district and local heating centres, and the remainder were consumed in the detached house sector. Sweden both imports and exports pellets.