ETH Zurich researchers have developed an innovative method to store hydrogen using abundantly available iron. They successfully stored 10 megawatt hours (MWh) of hydrogen on their campus for winter use. This novel storage solution is ten times cheaper, safer, and longer-lasting than existing methods.
The Rusting Process: Key to Energy Storage and Retrieval
The innovative system’s energy storage and retrieval process relies on the common phenomenon of iron rusting. The researchers use the 19th-century steam-iron process to store hydrogen in iron. The process involves:
- Pumping hydrogen gas into a stainless steel reactor containing iron ore
- Maintaining the iron ore at 752 Fahrenheit (400 degrees Celsius)
- Hydrogen extracting oxygen from iron oxide or rust, forming water and iron
- The process mimicking battery charging, storing energy in water and iron
- Energy retention for months without significant losses
Reversing the Process for Energy Generation
During winter months, when energy demand is high, researchers introduce hot steam into the reactors. This reverses the storage process, forming rust and releasing hydrogen gas. The released hydrogen generates electricity in a fuel cell or burns as fuel.
Advantages of Iron-Based Hydrogen Storage
The storage option’s greatest advantage lies in its simplicity and cost-effectiveness. The materials used do not require preprocessing and can be easily scaled without significantly impacting iron market prices. Adding more reactors increases onsite storage capacities, and the material can be recycled for years.
Pilot Facility and Future Plans
ETH researchers constructed a pilot facility consisting of three reactors at the Hönggerberg campus. The facility stores 10 MWh of hydrogen, which could yield 4-6 MWh of energy when converted back. Despite the technology losing up to 60 percent of energy during conversion, researchers eagerly plan to test it on a larger scale. They aim to store 4 gigawatt hours (GWh) in reactors with a 2,000 cubic meter volume. This could meet one-fifth of the campus’ winter energy requirements using summer-trapped energy.
Professor Wendelin Stark, the research team leader, stated that this plant could replace a small reservoir in the Alps. It equates to around one-tenth of the Nate de Drance pumped storage power plant’s capacity.
As Switzerland aims to reduce fossil fuel dependence, this innovative hydrogen storage solution could play a crucial role. It can help overcome the seasonal mismatch between solar energy availability and energy demand, supporting the country’s goal of sourcing 40 percent of its energy needs from solar by 2050.its energy needs from solar by 2050.
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