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Significance Statement
The methodology of life cycle assessment is used to explore the environmental impacts of different waste to energy technologies and the production of methane from municipal solid waste (MSW) is considered for the UK situation. The results are analysed according to two perspectives: a waste management perspective and an energy production perspective. Hence, the study seeks an answer to the two questions: ‘What is the best waste management process for waste disposal?’ and ‘What is the best technology for production of renewable methane?’ Five different scenarios are analysed and the focus is on an advanced gasification and plasma technology compared to biological alternatives including i) mechanical pre-treatment of MSW associated with the anaerobic digestion of the organic fraction and landfill/incineration of residual waste; ii) anaerobic digestion of source separated waste and landfill/incineration of residual waste. The advanced thermal process includes municipal solid waste pre-treatment and metal recovery, waste treatment in gasifier and in high temperature plasma converter unit followed by cooling and cleaning of the syngas. This is finally transformed into methane thanks to the methanation and upgrading processes.
For each perspective analysed (waste management and methane production), the comparison is firstly performed considering the current UK energy mix and then extended to include future energy mix scenarios in the UK. Therefore, the research predicts the environmental impacts of biological and thermal technologies for waste treatment for the next 2 decades, and identifies trade-offs between the two. The research also compares the environmental impacts of anaerobic digestion processes from source and centrally separated organic waste and identifies hot spots. Thermal and biological waste treatment processes are compared using a ‘cradle-to-grave’ approach in order to identify the best environmental solution for waste disposal. The research work is published in Journal of Cleaner Production.
For the waste management perspective, the results of the research shows that, currently, processes with higher electric efficiency determine a lower global warming potential. However, as the electricity mix in the UK becomes less carbon intensive and the natural gas mix increases the carbon intensity, processes with higher renewable methane yield achieves a lower global warming impact within the next 20 years. When the perspective of energy production is considered, more efficient technologies for renewable methane production give a lower global warming for both current and future energy mix. In addition to the global warming potential other key environmental impacts (resource depletion, acidification potential, water toxicity, etc.) are considered, and, hence, this study can guide public authorities to make better environmental choices.
Journal Reference
Tagliaferri1,2, Evangelisti1, Clift3, Lettieri1, Chapman2, Richard Taylor2. Life cycle assessment of conventional and advanced two-stage energy-from-waste technologies for methane production. Journal of Cleaner Production, Volume 129, 2016, Pages 144–158.
[expand title=”Show Affiliations”]- Department of Chemical Engineering, University College London, Torrington Place London, WC1E 7JE, UK.
- Advanced Plasma Power (APP), Unit B2, Marston Gate, South Marston Business Park, Swindon, SN3 4DE, UK.
- Centre for Environmental Strategy, The University of Surrey, Guildford, Surrey, GU2 7XH, UK.
Go To Journal of Cleaner Production
