Original Research Article Life cycle environmental performance of miscanthus gasification versus other technologies for electricity production Thu Lan T. Nguyen ⇑ , John E. Hermansen Department of Agroecology, Aarhus University, Tjele, Denmark article info Article history: Received 2 June 2014 Revised 31 October 2014 Accepted 8 December 2014 Keywords: Miscanthus Energy crop Gasification technology Life cycle assessment abstract In this paper, the life cycle environmental performance of miscanthus gasification for electricity produc- tion in Denmark is evaluated and compared with that of direct combustion and anaerobic digestion. Fur- thermore, the results obtained are compared to those of natural gas to assess the potential of miscanthus as an energy source. Our results indicate that production of 1 kWh electricity from miscanthus via gas- ification leads to a global warming potential (100-year GWP) of 26 g and 296 g CO 2 e, without and with consideration of CO 2 emissions from indirect land use change respectively. For other impact categories, the production results in non-renewable energy use of 0.6 MJ primary, acidification of 1.6 g SO 2 e, eutro- phication of 7.8 g NO 3 e and respiratory inorganics of 0.1 g PM2.5e. Of the three alternatives, gasification is found to have the best performance in all impact categories considered, with the exception of non- renewable energy use where anaerobic digestion performs best. Our results also show that replacing nat- ural gas with miscanthus reduces global warming and non-renewable energy use. The results of the study are region-specific, i.e., valid for Denmark, but we believe that the general conclusions are applicable to those regions/areas with similar conditions. Ó 2014 Elsevier Ltd. All rights reserved. Introduction Biomass technologies for energy production As the reserves of non-renewable fossil fuels are being con- sumed faster than being produced through natural processes and the level of atmospheric CO 2 is rising rapidly, efforts to find low- carbon alternative energy sources are ongoing. Popular alternative energy sources being considered for electricity production nowa- days include biomass, wind, solar and hydropower, of which bio- mass is one of the most common and widespread resources in the world [1]. Energy stored in biomass e.g. energy crops, wood waste and crop residues, can be extracted by either direct combus- tion as the most simple way or conversion into gaseous fuels like biogas and syngas and then combustion of these intermediate energy carriers. Anaerobic digestion for biogas production from biomass feedstocks, in particular those with high moisture content, is another means of extracting energy from biomass. The process takes place in the absence of air at slightly elevated temperatures. In contrast, gasification which converts low-moisture biomass into syngas, is a less mature technology than anaerobic digestion, tak- ing place in the presence of a limited amount of air at moderately high temperatures. From a resource conservation point of view, gasification is regarded as an advanced and efficient method to extract energy from different biomass sources. In a recent study, Nguyen et al. [2] assessed the environmental performance of straw gasification for electricity production and compared it with that of straw-fired and fossil fuel-fired electricity production. In the com- parison with fossil fuels, the authors found that, despite the entailed environmental costs of removing the crop residues as opposed to retuning to soils, using straw gasification for electricity production in place of coal and natural gas consistently offers envi- ronmental benefits in global warming, non-renewable energy use and eutrophication. They also noted that a clear advantage of using crop residues as a primary energy source over energy crops is that it does not necessarily induce land competition with food thus avoiding indirect land use change. In recent years, land use change has been proven to be a leading cause of rising atmospheric CO 2 and resultant global climate change. The use of crop residues like cereal straw for energy however faces the issue of supply chain uncertainty since the production of straw, a by-product of grain production, is determined by the demand for grain. http://dx.doi.org/10.1016/j.seta.2014.12.005 2213-1388/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +45 87157768. E-mail address: thulannguyenthi@gmail.com (T.L.T. Nguyen). Sustainable Energy Technologies and Assessments 9 (2015) 81–94 Contents lists available at ScienceDirect Sustainable Energy Technologies and Assessments journal homepage: www.elsevier.com/locate/seta