Power generation from wind and solar sources is growing in importance, but requires back up from fossil fuel plants, greatly compromising fossil fuel plant economics. This includes the economics of most proposed IGCC-Hypogen type plant schemes which are intended to produce hydrogen and electricity, as well as capturing CO2. IGCC-Hypogen plants, however, that are able to change the ratio of hydrogen to electricity will be able to operate at maximum capacity all of the time, switching from power generation to hydrogen production as the demand for these two forms of energy changes. Because of the need to provide power to the TGCC-Hypogen ancillaries, some hydrogen from the plant will have to be utilised to supply some of this power. A preliminary economic study examines how the plant Could produce electricity and hydrogen at competitive prices. (C) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.