Systems based on hypo-eutectic Mg–Mg2Ni alloys for medium to large scale hydrogen storage and delivery

•High performance, low cost hydrogen storage systems are in development based on a Mg–Mg2Ni alloy.•These systems have higher storage density than compressed gas•They can be filled with hydrogen at low pressure, removing the need for a compressor•The systems can deliver hydrogen at a lower cost per unit of hydrogen delivered than compressed gas.•The metal hydride systems also have significant safety advantages over compressed gas.

Magnesium based metal hydrides have a number of attractive properties for hydrogen storage, particularly the high storage density and the safety benefits of low pressure operation. A hypo-eutectic Mg–Mg2Ni alloy has been developed. The material can be produced at a much lower cost than ball-milled materials while achieving a reversible storage of 6.5–7 wt% hydrogen at a rate of reaction that is acceptable for existing industrial applications.This alloy has been employed in a series of increasingly large prototype systems, reaching commercial scale in 2010 with a system storing 22 kg of hydrogen, appropriate for industrial merchant applications. The technology is also under development for larger scale applications such as refueling infrastructure and energy storage. This paper will discuss the potential applications of these systems and their technical and economic comparison to traditional compressed gas hydrogen storage and delivery.