The role of energy from waste in circular economy and closing the loop concept – Energy analysis approach

Security of energy supply and the threat of climate change are the key challenges that define the further development of EU energy systems. The security of supply problem follows other problems such as energy and material scarcity, import dependency and waste generation. These problems can be alleviated via development of a low-carbon, sustainable, competitive and resource-efficient economy. One of the pillars of this approach is a circular economy and “closing the loop” approach. Integrated waste management system can close the loop, not only material-wise, through material recovery, but also energy-wise, by using energy from waste to drive whole waste management and recovery chain. Such approach is utilized in this paper through tracking of each energy vector and calculating coverage of energy needs inside the analysed systems. Energy analysis is accepted approach for sustainability assessment of the various products and systems, where primary energy consumption approach is mostly used. By combining these two approaches, the impact of closing the loop material- and energy-wise on the sustainability of the recycled materials is assessed by analysing to which degree can the embodied energy of recycled materials be reduced. The results of the analysed city case study show that energy recovery can satisfy up to 60/50% (in 2020/2030) of the total energy needs of the analysed system; in 2030 38% of waste routed to energy recovery (from which 25% to anaerobic digestion and the rest to the incinerator) satisfies around 50% of energy needs. This internal (partial) coverage of systems energy needs can additionally reduce embodied energy of recycled materials, and increase their sustainability (primarily lowered by material recovery) by 11–67% at the same time. From these results it can be concluded that energy recovery of waste could help to “close the loop” in the whole waste recovery mindset.