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Research article - Peer-reviewed, 2014

Climate impact and energy efficiency from electricity generation through anaerobic digestion or direct combustion of short rotation coppice willow

Ericsson, Niclas; Nordberg, Åke; Sundberg, Cecilia; Ahlgren, Serina; Hansson, Per-Anders

Abstract

Short rotation coppice willow is an energy crop used in Sweden to produce electricity and heat in combined heat and power plants. Recent laboratory-scale experiments have shown that SRC willow can also be used for biogas production in anaerobic digestion processes.Here, life cycle assessment is used to compare the climate impact and energy efficiency of electricity and heat generated by these measures. All energy inputs and greenhouse gas emissions, including soil organic carbon fluxes were included in the life cycle assessment. The climate impact was determined using time-dependent life cycle assessment methodology.Both systems showed a positive net energy balance, but the direct combustion system delivered ninefold more energy than the biogas system. Both systems had a cooling effect on the global mean surface temperature change. The cooling impact per hectare from the biogas system was ninefold higher due to the carbon returned to soil with the digestate.Compensating the lower energy production of the biogas system with external energy sources had a large impact on the result, effectively determining whether the biogas scenario had a net warming or cooling contribution to the global mean temperature change per kWh of electricity. In all cases, the contribution to global warming was lowered by the inclusion of willow in the energy system. The use of time-dependent climate impact methodology shows that extended use of short rotation coppice willow can contribute to counteract global warming. (C) 2014 Elsevier Ltd. All rights reserved.

Keywords

Land use change; Soil carbon; Life cycle assessment; Time-dependent climate impact; Biogas; Combined heat and power

Published in

Applied Energy
2014, volume: 132, pages: 86-98

Authors' information

Swedish University of Agricultural Sciences, Department of Energy and Technology
Swedish University of Agricultural Sciences, Department of Energy and Technology
Swedish University of Agricultural Sciences, Department of Energy and Technology
Swedish University of Agricultural Sciences, Department of Energy and Technology
Swedish University of Agricultural Sciences, Department of Energy and Technology

Sustainable Development Goals

SDG7 Affordable and clean energy
SDG13 Climate action

UKÄ Subject classification

Environmental Sciences related to Agriculture and Land-use
Environmental Sciences
Renewable Bioenergy Research

Publication Identifiers

DOI: https://doi.org/10.1016/j.apenergy.2014.06.049

URI (permanent link to this page)

https://res.slu.se/id/publ/59768