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Enabling circular energy

A revolutionary method of storing energy in a circular and CO2-free manner

The Challenge

CO2 emissions

For a livable future, we must cut our CO2 emissions drastically. Over 40% of the world’s CO2 emissions are caused by electricity and heat-producing industries and the maritime transport sector. Currently, these industries cannot completely bring this 40% down to 0% because the existing carbon-free energy alternatives, just do not offer an efficient and cost-effective solution to every application, while meeting process requirements.


iron fuel

Looking towards the future, SOLID and its partners bring forward a revolutionary solution, advocating iron as a fuel. Iron fuel is circular, compact, CO2-free and cost-effective. Besides that, it’s also easy to store, scalable and safe, making it the green solution for the electricity and heat producing industries and the maritime transport sector.

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The practice of energy storage in iron fuel is a circular process that consists of multiple stages. These stages are as follows. Want to learn more about iron fuel? Click here.


Iron fuel is combusted with air, inducing a tremendous energy release. The energy released can be applied in various applications such as chemical processes, generation of electricity, or used as a means of propulsion.


Besides the production of heat, the only side-product created is iron oxide, better known as rust. The rust that is created during combustion is captured, ready to be recycled in the next process step.


The possibility to transform the captured rust back to iron fuel again is what makes iron fuel unique. This process is called reduction. In essence, this is the operation of storing renewable energy – like solar and wind energy – in a compact energy carrier: iron fuel.


The generated iron fuel in the reduction process can be stored and transported in a cheap and safe manner with hardly any energy losses. As a result, iron fuel enables energy provision, wherever and whenever.


Innovative & enjoyable

SOLID is an ambitious student team of Eindhoven University of Technology that aims to enable access to clean and renewable energy for anyone, at any time. With 30 interdisciplinary students, we create an ecosystem for iron fuels as circular energy carriers. To do so, SOLID participates in multiple consortia and works with partners to develop both the technology and the ecosystem. Being part of SOLID means being part of an innovative and most enjoyable community. In our journey towards making iron fuel a success, we lay the foundation for a sustainable future.


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