At present, hydrogen is largely used in refineries and ammonia plants but in future it may be used as an energy carrier for vehicles, power generation and distributed heat production. One of the most promising technologies for hydrogen production with low CO2 emissions is coal gasification with CO2 capture and storage. Hydrogen can be co-produced with electricity in Integrated Gasification Combined Cycle (IGCC) plants. This paper summarizes the results of studies carried out by Foster Wheeler Italiana for the IEA Greenhouse Gas R&D Programme (IEA GHG). Performance and costs data are presented for five different coal gasification plants producing electricity and/or hydrogen with and without CO2 capture. The cost data are on a 2nd quarter 2008 basis and take account of the recent large increases in plant investment costs and coal prices. The paper assesses possible advantages of hydrogen and electricity co-production in future energy supply systems and the advantages of being able to operate plants flexibility to meet the varying demands for hydrogen and electricity. If hydrogen becomes used as an energy carrier it will displace some of the demands for natural gas, gasoline and diesel fuel. A market analysis of the demands for these fuels was performed for The Netherlands and the USA to determine possible future hydrogen demand and how it will vary throughout the year. Demands for electricity were also determined. Plant performance and costs are estimated and electric power production costs are evaluated. Electricity and hydrogen co-production plants are compared to plants that produce electricity only, with and without CO2 capture, to evaluate the cost of CO2 avoidance. The benefits of flexible co-production with and without buffer storage of hydrogen are also evaluated.