This paper presents the technical and economic performance of energy-from-waste (EfW) fluidized bed combustion and gasification processes and reports on the implications of different scales and technologies on costs and efficiencies. Mass and energy balances of the processes were performed and the cost effectiveness of the different waste treatment options. for the generation of electric power, was assessed using a discounted cash flow analysis. For the different waste treatment options, the study concludes that gasification processes have higher overall system efficiencies than combustion processes. In particular, fluidized bed gasification with combined cycle gas turbine (CCGT) is the most attractive treatment option in terms of cost and efficiency. Although fluidized bed gasification has limited commercial operation in the UK, they are compatible with high levels of source segregation and, therefore, have the potential to contribute towards integrated waste management practices. The operational reliability of the systems will be further improved as more facilities are commissioned and operated at commercial scales. Furthermore, financial incentives, such as Renewable Obligation Certificates (ROCS), supportive policies and active R&D by major industry players and research institutions are important factors for the full commercialisation of the gasification processes, especially, for plant scales larger that 50 ktpa. (C) 2008 Elsevier B.V. All rights reserved.