Hydrexia’s patented storage and delivery systems provide inherent economic, practical and safety advantages over compressed gas hydrogen storage.
A detailed economic analysis of transporting hydrogen with Hydrexia’s solid state hydrogen storage system compared to typical compressed gas tube trailers was performed taking into account the local costs and regulations in several regions.
The analysis explored the distribution cost of storing and delivering hydrogen for compressed gas and for the metal hydride system in four regions: Europe, USA, China and Japan.
Comparing compressed gas delivery to solid state storage delivery by metal hydride systems
- The model is based on a set of 12 customers, each consuming 250kg of hydrogen per day and requiring at least two days of storage on site to cover days when a delivery is not possible.
- The hydrogen is produced in a central location at 0.8MPa (absolute), by an electrolyser or a steam methane reformer, at a rate of 3000kg/day to serve the 12 customers.
- The average distance between the hydrogen supply and customers and average distance between customers are also used to model the distribution costs. This allows the model to calculate the costs over a range of distances.
- The metal hydride systems are filled directly from the 0.8MPa source while the hydrogen for the compressed gas trucks is compressed to 20MPa to 45MPa depending on the region (all pressures are absolute).
- The metal hydride system contains 250kg of hydrogen and three units can be carried on a delivery truck in Europe, USA or Japan while four units can be carried in China due to the higher weight limits on road transportation trucks.
- Similarly, the amount of hydrogen transported as compressed gas varies according to the pressure and the truck weight limitations, ranging from 220kg to 430kg of hydrogen per truck. In order to meet the two day on-site storage requirement, two metal hydride units must be kept at each customer’s site.
A typical case was modelled where the customers are 100km from the hydrogen generation site and 30km from each other. With compressed gas trucks, one trailer is delivered to one customer as needed and the empty one is brought back to the hydrogen supply for filling, requiring 12 trips of 200km for a total of 2400km.
The time between deliveries varies according to the hydrogen storage capacity per truck in the respective regions but all see distinct advantages. With the metal hydride systems, a truck carries multiple units and can therefore supply multiple customers in one trip. In the case of Europe, USA and Japan four trucks travel a total of 1040km to supply the 12 customers, while in China three trucks travel a total of 870km to supply the 12 customers.
1. Solid state hydrogen storage is more economical than compressed gas
Hydrexia’s solid state hydrogen storage systems have the potential to significantly reduce the cost of distributing hydrogen compared to compressed gas due to their higher storage densities and low cost. At the same time, the systems provide major safety advantages over existing gaseous and liquid hydrogen storage and distribution, due to both the low pressure and the small volumes of free gas that can escape in the event of a vessel rupture.
2. Significantly lower distribution costs
In Europe, USA and Japan the metal hydride system has significantly lower distribution costs regardless of the average distance to the customer, although the gap widens as the distance increases. In China the costs of the two systems are similar at short distances, but at higher distances the metal hydride system becomes increasingly more economical than compressed gas. The main differences in China compared to the other regions are the lower cost of labour and the lower capital costs for compressed gas equipment. The increase in the distribution cost per distance (slope of the curves) is mainly dependent on the transportation weight limit, fuel costs and driver’s wage in each region.
3. Lower capital expenses
The capital expenses are lower in all regions for the metal hydride systems compared to compressed gas. The main capital savings are in three areas: first, Hydrexia’s metal hydride storage systems are less expensive than compressed gas storage equipment; second, the metal hydride system can be filled at 0.8MPa (absolute), thereby eliminating the need for high pressure gas compressors; and third, fewer trucks are required to transport the hydrogen to the customers.
4. Reduced distributor operating expenses
The distributor’s operating expenses are lower in all regions for the metal hydride systems compared to tube trailers. The energy required to compress the gas at the filling site is eliminated, and there is less fuel and labour associated with delivering the gas to the customer.
This article was adapted from our whitepaper “Systems based on hypo-eutectic Mg–Mg2Ni alloys for medium to large scale hydrogen storage and delivery” published in Journal of Alloys and Compounds. Contact us for the full article.