Co-gasification of solid waste and lignite – A case study for Western Macedonia N. Koukouzas a, * , A. Katsiadakis a , E. Karlopoulos a , E. Kakaras a,b a Centre for Research and Technology Hellas (CERTH)/Institute for Solid Fuels Technology and Applications (ISFTA), 4th km N.R. Ptolemais-Kozani, 502 00 Ptolemais, Greece b Laboratory of Steam Boilers and Thermal Plants, Mechanical Engineering Department, National Technical University of Athens, Heroon Polytechniou Ave., 157 80 Zografou Athens, Greece Accepted 26 April 2007 Available online 13 July 2007 Abstract Co-gasification of solid waste and coal is a very attractive and efficient way of generating power, but also an alternative way, apart from conventional technologies such as incineration and landfill, of treating waste materials. The technology of co-gasification can result in very clean power plants using a wide range of solid fuels but there are considerable economic and environmental challenges. The aim of this study is to present the available existing co-gasification techniques and projects for coal and solid wastes and to inves- tigate the techno-economic feasibility, concerning the installation and operation of a 30 MW e co-gasification power plant based on inte- grated gasification combined cycle (IGCC) technology, using lignite and refuse derived fuel (RDF), in the region of Western Macedonia prefecture (WMP), Greece. The gasification block was based on the British Gas-Lurgi (BGL) gasifier, while the gas clean-up block was based on cold gas purification. The competitive advantages of co-gasification systems can be defined both by the fuel feedstock and production flexibility but also by their environmentally sound operation. It also offers the benefit of commercial application of the process by-products, gasification slag and elemental sulphur. Co-gasification of coal and waste can be performed through parallel or direct gasification. Direct gasification constitutes a viable choice for installations with capacities of more than 350 MW e . Parallel gasification, without extensive treatment of produced gas, is rec- ommended for gasifiers of small to medium size installed in regions where coal-fired power plants operate. The preliminary cost estimation indicated that the establishment of an IGCC RDF/lignite plant in the region of WMP is not profitable, due to high specific capital investment and in spite of the lower fuel supply cost. The technology of co-gasification is not mature enough and therefore high capital requirements are needed in order to set up a direct co-gasification plant. The cost of electricity estimated was not com- petitive, compared to the prices dominating the Greek electricity market and thus further economic evaluation is required. The project would be acceptable if modular construction of the unit was first adopted near operating power plants, based on parallel co-gasification, and gradually incorporating the remaining process steps (gas purification, power generation) with the aim of eventually establishing a true direct co-gasification plant. Ó 2007 Elsevier Ltd. All rights reserved. 0956-053X/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.wasman.2007.04.011 Abbreviations: BGL, British Gas-Lurgi; CFB, circulating fluidised bed; CHP, combined heat and power; COS, carbonyl sulphide; DEC, delivered equipment cost; HRSG, heat recovery steam generator; IGCC, integrated gasification combined cycle; MDEA, methyl diethanol amine; MSW, municipal solid waste; PPC, process plant cost; PPC S.A., Public Power Corporation S.A.; RES, renewable energy sources; RDF, refuse derived fuel; SCOT, shell claus off-gas treatment; TCR, total capital requirement; TPC, total plant cost; TPI, total plant investment; WID, waste incineration directive; WMP, Western Macedonia prefecture. * Corresponding author. Tel.: +30 2106546637; fax: +30 2106527539. E-mail address: koukouzas@techp.demokritos.gr (N. Koukouzas). www.elsevier.com/locate/wasman Available online at www.sciencedirect.com Waste Management 28 (2008) 1263–1275