New Publication – Trends and drivers in alternative thermal conversion of waste

Sep 2020

This report –Trends-and-drivers-in-alternative-thermal-conversion-of-waste, prepared by IEA Bioenergy Task 36, discusses both trends impacting solid waste management systems within EU countries as well as selected alternative thermal treatment technologies such as pyrolysis and gasification. Aspects concerning technology readiness and affordability are highlighted as well as the need to combine mechanical waste pretreatment and sorting with thermochemical treatment in order to increase recycling rates and to improve economics.

Key messages:

  • Thermochemical processes pyrolysis and gasification are thermal separation processes for mixed wastes including plastics, biomass and mineral fractions. Thermal technologies for chemical recycling still need R&D efforts specifically concerning the flexibility to process varying complex mixed feedstocks and the scale of processing.
  • When focused on power and heat production from waste, alternative thermal waste treatment technologies are mostly not competitive with waste incineration due to higher process complexity / specific capital investment. Chemical recycling, with associated product revenues can make the difference.
  • Chemical recycling complements mechanical sorting by overcoming the downcycling issues of mixed materials and by avoiding final incineration of large amounts of separately collected wastes. Combined mechanical and chemical recycling thus maximizes the recycling rate and minimizes the greenhouse gas emissions.
  • Promoting alternative thermal waste treatment technologies such as pyrolysis and gasification goes along with waste management system optimization for the overall aim to reduce greenhouse gas emissions and to minimize the environmental impact.

Figure: example of material flows in fluidized bed gasification of residual household waste

Figure: example of material flows in rotary kiln pyrolysis of residual household waste