This paper reviews state-of-the-art developments in hydrogen energy systems which integrate fuel cells with metal hydride-based hydrogen storage. The 187 reference papers included in this review provide an overview of all major publications in the field, as well as recent work by several of the authors of the review. The review contains four parts. The first part gives an overview of the existing types of fuel cells and outlines the potential of using metal hydride stores as a source of hydrogen fuel. The second part of the review considers the suitability and optimisation of different metal hydrides based on their energy efficient thermal integration with fuel cells. The performances of metal hydrides are considered from the viewpoint of the reversible heat driven interaction of the metal hydrides with gaseous H2. Efficiencies of hydrogen and heat exchange in hydrogen stores to control H2 charge/discharge flow rates are the focus of the third section of the review and are considered together with metal hydride-fuel cell system integration issues and the corresponding engineering solutions. Finally, the last section of the review describes specific hydrogen-fuelled systems presented in the available reference data.IS

Because of the depletion of fossil fuels and because of the growing adverse impact on the environment caused by the utilization of fossil fuels, researchers are investigating fuels which are renewable and which are environmentally compatible. In order to compare the fuel candidates, criteria have been developed, which make it possible to rank them in order of merit. Among all the fuels considered, hydrogen stands out as the best. The paper compares hydrogen with other conventional and unconventional fuels, and comes to the conclusion that in every count hydrogen has the best characteristics with many unique and desirable properties.