Climate impact from peat utilisation in Sweden

Abstract

The climate impact from the use of peat for energy production in Sweden has been evaluated in terms of contribution to atmospheric radiative forcing. This was done by attempting to answer the question "What will be the climate impact if one would use 1 m 2 of mire for peat extraction during 20 years?". Two different methods of after-treatment were studied: afforestation and restoration of wetland. The climate impact from a peatland -wetland energy scenario and a peatland -forestry energy scenario was compared to the climate impact from coal, natural gas and forest residues. Sensitivity analyses were performed to evaluate which parameters that are important to take into consideration in order to minimize the climate impact from peat utilisation.The main conclusions from the study are:• The accumulated radiative forcing from the peatland -forestry energy scenario is comparable to natural gas in a 180-year perspective, and between forest residues and natural gas in a longer perspective (300 years) assuming a medium-high forest growth rate and original methane emissions from the virgin mire.• The accumulated radiative forcing from the peatland -wetland energy scenario, will lie between coal and 2/3 of natural gas in a 300-year perspective, depending on the assumed carbon uptake rates for the wetland and assuming a medium-high methane emissions from a restored wetland.

Climate effects of bioenergy from forest residues in comparison to fossil energy

“…Forest residues can be used in numerous ways for climate change http://dx.doi.org/10.1016/j.apenergy.2014. 10.013 0306-2619/Ó 2014 Elsevier Ltd. All rights reserved. mitigation and oil use reduction [7].…”

“…The forest residues gave the lowest radiative forcing of all the fuels, although the authors assumed a very rapid decomposition rate for biomass left in the forest. Zetterberg [10] used the approach to compare the use of peat, coal, fossil gas, and forest residues. The analysis focused on peat use, and included different management options for peat land after peat extraction.…”

Time-dependent radiative forcing effects of forest fertilization and biomass substitution

“…Korhonen et al (1993) used a similar approach to compare scenarios of future fossil fuel use in Finland. Zetterberg et al (2004), Nilsson and Nilsson (2004), and Kirkinen et al (2007) used the approach to compare the use of fossil fuels and peat fuel, and included different management options for peat land after peat extraction. Holmgren et al (2007) compared the radiative forcing effects of using fossil fuels or forest residues for energy, considering the time dynamics of biomass decay if residues are left in the forest.…”

Can we produce carbon and climate neutral forest bioenergy?

“…Forest residue bioenergy has a warming impact on the climate because of the timing of the emissions and the slow removal of CO 2 from the atmosphere (Zetterberg et al ., ; Holmgren et al ., ; Kirkinen et al ., ; Sathre & Gustavsson, ; Repo et al ., ). Therefore, carbon balance calculations that assume that the growing forest offsets the ‘upfront’ bioenergy emissions result in an overestimation of the true climate change mitigation potential of forest bioenergy (Kendall et al ., ; Cherubini et al ., ; Pingoud et al ., ).…”

“…Therefore, carbon balance calculations that assume that the growing forest offsets the ‘upfront’ bioenergy emissions result in an overestimation of the true climate change mitigation potential of forest bioenergy (Kendall et al ., ; Cherubini et al ., ; Pingoud et al ., ). In order to take account of both the time‐dependence of the GHG fluxes and the atmospheric residence times of GHGs, the potential climate impact impacts must be assessed with a more comprehensive metric than the carbon balance calculations alone, such as radiative forcing (RF) (Zetterberg et al ., ; Holmgren et al ., ; Kirkinen et al ., ; Sathre & Gustavsson, ).…”