Are the aims of increasing the share of green electricity generation and reducing GHG emissions always compatible?

Energy from waste (EfW) has been identified as a source of ‘green electricity’ and has been used as a way of reducing greenhouse gas (GHG) emissions. Nevertheless, selecting an EfW strategy for municipal solid waste management is a challenging task not least because of the uncertainty involved in quantifying the potential economic and environmental impacts. This paper analyses five alternatives for managing the municipal solid waste of Sydney for their ‘green electricity’ and GHG savings potential under conditions of uncertainty. The impact of paper recycling on the ranking of alternatives was investigated, too. Our analysis shows that maximizing EfW generation potential does not result in greater GHG saving. A combination of food and green waste composting, recycling of metals, paper, glass and plastics while only landfilling waste fractions that are not recyclable may result in the best GHG savings. Furthermore, recycling of paper does not always achieve the best outcome; anaerobic digestion or composting may yield better results from an environmental and energy generation perspective.

► Greenhouse gas reduction through energy from waste is investigated using LCA.
► Max ‘green electricity’ generation does not always correspond to max GHG savings.
► Total energy savings is a better measure of GHG savings.
► The philosophy behind setting ‘green electricity’ target should be transparent.