ETH Zurich researchers have introduced a groundbreaking approach to hydrogen storage, using iron in a cost-effective, safe, and durable manner. By leveraging rusting, a natural oxidation process, they have converted 10 MWh of hydrogen into a storable form with minimal loss of capacity over several months. This promising technology presents a potential solution for balancing seasonal energy demands, particularly in regions with variable renewable energy availability such as Switzerland.
In the quest for sustainable energy solutions, a team from ETH Zurich has made a significant stride with their pioneering use of iron for hydrogen storage. The process involves three stainless steel reactors with six-millimeter-thick walls, wherein iron ore undergoes a reaction at 752 Fahrenheit (400 degrees Celsius), facilitated by the steam-iron process dating back to the 19th century.
The chemical process effectively ‘charges’ iron by utilizing hydrogen to strip oxygen from iron oxide, resulting in water and pure iron. This chemical reaction allows the storage of energy in an alternative form that can be kept without significant degradation for months. During peak energy demand in winter, the stored hydrogen can be released by reversing the rusting process through the introduction of steam. The recovered hydrogen can either be converted into electricity via fuel cells or combusted directly to power turbines.
This technique has the distinct advantage of being cost-effective due to the low cost and wide availability of iron. The research team has demonstrated the feasibility of the process on their campus, where they can store enough hydrogen to account for a substantial portion of their winter energy needs. They aim to scale up the project to store 4 gigawatt-hours, which could provide a fifth of campus energy in the colder months.
Recognizing that the conversion process can result in up to a 60 percent energy loss, the team at ETH Zurich is mainly focused on the long-term potential for scaling and efficiency. They assert that despite the losses, the technology could be nearly ten times cheaper than current hydrogen storage methods, providing an attractive option for seasonal energy storage.
Source: https://interestingengineering.com/energy/hydrogen-storage-iron-rust-battery
