If targets are met, Europe will be drawing twenty percent of its energy supply from renewable sources by the end of the decade. Many of the EU’s twenty-eight member states are beginning to develop advanced technologies to harness wind, water and solar power. But what happens when the wind isn’t blowing, the sun isn’t shining and there are no bodies of water large enough to sustain hydropower? A cooperative project between European and Japanese researchers is now developing specialised metal-hydride materials that can efficiently and cheaply store renewable energy in the form of hydrogen.

The ability to store renewable energy and tackle the uneven distribution of sustainable resources is paramount to its viability as a power source, particularly for the transport industry. Since the Fukushima power plant accident in 2011, the Japanese government has been working toward a policy of denuclearisation, likewise adopting and investing in advanced renewable energy technologies. One answer to the storage challenge has been the Totalised Hydrogen Energy Utilisation System (THEUS), a concept developed in Japan by the National Institute of Advanced Industrial Science and Technology (AIST) that uses hydrogen as the energy carrier with the primary energy produced from renewable sources.

Now, a large multilateral cooperation between European and Japanese researchers is working hard to improve upon the initial concept and design an unprecedented next generation hydrogen-based energy storage system in the iTHEUS project. Coordinating iTHEUS is Professor Bjørn C. Hauback, an adjunct professor of physics at the University of Oslo and head of the physics department at Norway’s Institute for Energy Technology (IFE). As a part of CONCERT-Japan, one of the EU’s international cooperation activities, iTHEUS is striving both to make a significant contribution toward renewable energy storage and to foster deeper ties between European and Japanese scientific research.

The storage of hydrogen can occur in several ways with varying degrees of energy and cost efficiency. Chemical compounds, so called metal hydrides, offer a practical solution. “When you store hydrogen in solid materials you can store the same amounts in smaller volumes than with other methods,” explains Hauback. In order to use the hydrogen, however, it must be released from the metal hydride it has formed. The reversibility of the process is therefore essential to the viability of metal hydrides as a suitable approach to hydrogen storage, and the high temperatures needed for desorption of light-weight compounds can ramp up costs in energy and efficiency.

In order to bring this technology up to a level where it is ready to be used for large-scale renewable energy, iTHEUS needs lightweight storage media, a large holding capacity and the ability to store and release hydrogen in a more energy and cost efficient manner. To this end, Hauback is exploring the possibility of using novel storage materials with high rates of uptake and release at moderate conditions. “The basic science here is the development of new compounds and new materials,” says Hauback. “The challenge is understanding how to make them, what their properties are and how to characterise them.” With these, the goal is to examine their performance after integration into an enhanced system using efficient solid oxide or high temperature PEM fuel cells.

There are, of course, certain challenges involved in such a large multilateral cooperation effort. As well as the challenge of combining applied and basic research, iTHEUS brings together the science of very different European and Japanese cultures. With more and more nations gearing up toward a large-scale implementation of renewable energy technologies, however, it is crucial to establish and maintain the kinds of relationships fostered by iTHEUS. Through them, the speed of progress is significantly increased and along with it the promise of a sustainable, environmentally friendly energy supply.