The use of coal for large scale powered production meets a growing environmental concern. In spite of the fact that "clean" coal conversion technologies integrated with high-efficiency power production facilities, such as IGCC, are developed, the aim for sustainable development strives for a power production system based on renewable energy sources. One of the most promising renewable energy source that can be used in the Netherlands is biomass, i.e. organic waste materials and/or energy crops. To accelerate the introduction of this material, in a technical and economically acceptable way, co-gasification with fossil fuels, in particular coal, in large scale IGCC processes is considered. In this paper the technical feasibility, economic profitability, and environmentally acceptability of co-gasification of biomass in coal-fired oxygen-blown entrained-flow based IGCC process and three co-gasification concepts were defined for further consideration.