Greenhouse impact due to different peat fuel utilisation chains in Finland — a life-cycle approach

Greenhouse impacts of different peat fuel utilisation chains were studied. A life cycle approach was used in order to cover all important emissions and sinks due to activities linked to the peat fuel production and utilisation. Radiative forcing was used to describe the greenhouse impact, and the results are given per one petajoule of energy produced. Carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) emissions and sinks were considered. Investigated peat production reserves were pristine peatland (fen), forestry-drained peatland, and cultivated (cropland) peatland. The considered phases of the peat utilisation chain included peat fuel production, storage, transport, combustion and the after-treatment of the cut-away peatland. After-treatment alternatives were afforestation and restoration. The greenhouse impact of a considered peat fuel chain was calculated by subtracting the emissions/sinks of a production reserve in a state of non-utilisation from the emissions/sinks of peat utilisation chain. According to the results, the most climate-friendly peat production chain is cultivated peatland-afforestation. Cultivated peatland has large greenhouse gas emissions and these emissions from the land area are ceased by the removal of the peat layer, when the area is utilised for peat fuel production. If forestry-drained peatland or pristine fen is used for peat fuel production, the greenhouse impacts of these chains are of the order of the greenhouse impact of the utilisation chain for coal. Improvement of peat production and combustion methods can be applied to decrease to some extent the greenhouse effect of peat energy.