Hydrogen Storage Tank Systems and Materials Selection for Transport Applications

The present international socio-economic drive for renewable energy use for sustainable development with environmental protection directs attention to hydrogen as energy carrier. Hydrogen production and storage, and fuel cell (FC) technologies have been intensively worked on in Europe including European Commission (EC) supported projects via Framework Programs (FPs), as well as various national and international cooperative programs including those of International Energy Agency (IEA) and International Partnership for Hydrogen Economy (IPHE). The hydrogen storage is required for transport applications as dense as possible to achieve high gravimetric and volumetric density. The storage of hydrogen in liquid, gas and solid forms are associated with low temperature cooling, higher pressures up to 700 bar and integrated higher volume and weight, respectively. The liquid and pressurized gas storage systems are relatively advanced in present applications. On the other hand, the system safety and reliability, hence the public acceptance as well as economic feasibility have been the main drives for solid and hybrid hydrogen applications. The use of solid hydrogen is predicted by the automotive industry to ultimately dominate the hydrogen transport application market. The bottleneck in solid hydrogen application is metal hydride production to meet the quantitative targets for vehicles mainly following the US DOE goals set for years up to 2015. System requirements need also be met for a present target of e.g. 75kWel fuel cell cars aiming at a 400km driving distance with 4 kg of hydrogen. This necessitates a gravimetric storage density of over 6 wt. per cent. The present paper will address the hydrogen storage tank system for on-board applications including storage tank materials, system design, production technologies and system safety. An overview will be presented on the current state-of-the-art of European and international progress on storage materials integrated into on-board storage tank system. The European current programs on hydrogen storage technologies for transport applications including design, safety and system reliability will be addressed.