Life cycle assessment of peat utilisation in Finland

Environmental issues related to the production of peat and its use in energy generation have been the subject of public debate and research over the past few years in Finland. Peat is both an indigenous and a locally utilised fuel. Finland has no fossil fuel resources, and the transportation distances of imported fuels into Finland are normally long. In Finland the large peat resources can be utilised locally and peat-burning power plants are situated near the peatlands. Peat production and energy conversion methods are being continuously developed to make use of the environmentally and technically best available technology. In Finland peat formation exceeds peat utilisation and an increase in peat utilisation is therefore sustainable. The life cycle assessment concept gives an opportunity to evaluate and improve the environmental quality of peat utilisation options. The study focuses on an inventory analysis, but some of the most common methods of impact assessment with valuation are also included. The study also includes a comparison of fossil fuels and a discussion part. All the calculated results are based on net emissions. The background emissions of natural peatland are subtracted from the emissions of the utilisation phases. Milled peat and sod peat are reported in this study. Horticultural peat is studied simultaneously, but it will be reported later. The Sod Wave, Haku and Tehoturve methods are studied for the production of peat. The power plants of the study are Kempele heating plant and Rauhalahti cogeneration plant. The functional unit is 1 MWh produced total energy. The temporal boundaries vary from 112 to 128 years, depending on the peat production methods used. The restoration time is 100 years in all of the options. The emissions of greenhouse gases are based on the reports of The Finnish Research Programme on Climate Change). The water emissions are based on control monitoring reports from 1994 and 1995. The water emissions of the restoration phase are, however, poorly known at the moment. The Tehoturve method is today the method most commonly used in the production of milled peat, and it is gradually replacing the traditional Haku method. The Tehoturve method is environmentally better than the Haku method. The new Sod Wave method is the best method from the environmental point of view because the production time is shortest. The carbon dioxide emissions of the energy conversion phase make up the biggest share of the total carbon dioxide emissions: well over 90 % of the total amount. Combined heat and power production also gives environmentally better results than separate heat production. The results of the impact assessment mainly follow the inventory results. The airborne emissions of the energy conversion phase cause the biggest acidification and global warming effects. The peat production phase causes the biggest eutrophication effects. In the life cycle assessment the key factors of the peat utilisation options are the definition of boundaries, the life cycle time, the restoration mode and the peat production method used. This study also shows that the assessed restoration way and time give an opportunity to evaluate peat utilisation from different aspects of sustainability.