Hessel Jongebreur on Converting Solar Energy into E-Fuel

How did you come up with the idea for ZEF?

“I have been active at TU Delft for a long time, and ZEF is my third spin-off from this university. Previously, I founded a company that developed a device for tying rebar in concrete, which we eventually sold to an American manufacturer. After that, I worked on aerodynamics for trucks. That company was acquired by an automotive player, where I worked for several years.

ZEF is what I always call my final venture. I told myself, ‘I’ll do it one last time.’ Developing hardware is challenging but immensely enjoyable. After my work in aerodynamics, I wanted to take it a step further and focus on sustainable fuels. My co-founders also come from the TU Delft network. That’s how we started ZEF together.”

What does the name ZEF stand for?

“ZEF stands for Zero Emission Fuels. Our goal is to develop micro-factories that convert solar energy directly into methanol, a sustainable fuel. The demand for these fuels is growing because electricity cannot meet all energy demands across sectors. Aviation and shipping, for example, are difficult to electrify but contribute significantly to emissions. E-fuels provide a solution: sustainable fuels produced from renewable electricity.

Eight years ago, we started by analysing how solar or wind energy could be directly converted into fuel. Many technologies exist, but we chose solar energy due to its low cost in sun-rich areas. Instead of transporting electricity via the grid, we directly link energy generation to methanol production. This makes our technology unique.

Our micro-plants, roughly the size of a large refrigerator, are developed in the Netherlands in collaboration with TU Delft. They are directly connected to solar panels and convert the generated energy into methanol on-site, which is then stored. The more sunshine, the more fuel is produced. In addition to the university, we collaborate with various other colleges, research institutions, and companies.

Any location with year-round sunshine is suitable for this technology. Think of southern Europe (such as Spain, Portugal, and southern Italy), North Africa, Australia, Oman, Egypt, and parts of South America, like Peru and Colombia. By focusing on solar energy and directly combining energy generation with processing, we expect to achieve significant cost reductions and contribute meaningfully to the transition to sustainable fuels.”

How and to whom will you market the micro-plant and its components?

“We will offer our micro-plants to large solar park developers and Power-to-X companies. The concept replaces one large factory with thousands of small units, collectively producing the same amount of methanol. This approach offers economies of scale and has the significant advantage of not requiring grid connections. This makes them particularly suitable for sectors that are hard to electrify, such as shipping and aviation. While we will primarily supply the units, we will remain involved in monitoring and maintaining them.

In addition to complete micro-plants, we will also market individual components. Our micro-plant combines three processes:

• Direct Air Capture – extracts CO₂ and water from the air.

• Electrolysis – converts water into hydrogen.

• Methanol production – turns CO₂ and hydrogen into methanol.

These components can be used separately, for instance, in hydrogen projects or ammonia production. Thanks to our modular approach and mass production, we expect to significantly reduce equipment and installation costs.”

Why do you collaborate so much with students?

“When we started eight years ago, we wanted to keep costs low and build our development step by step. Students offer an ideal solution: they can work on prototypes that don’t need to be expensive. Moreover, we enjoy working with young people. They are the engineers of the future, and we give them the opportunity to work on the technologies of tomorrow.

Together with student teams, under the guidance of our technical team, we have built a wealth of knowledge and experience. It’s a great way to develop both our technologies and talent.”

Why are you participating in the NXTGEN project?

“For our micro-plants, we need technologies to produce them on a large scale. Within the NXTGEN programme, we focus on prototype development and production processes. Collaborating with partners, such as specialists in plastic injection moulding or assembly lines, helps us share knowledge and accelerate progress.”

What do you hope to achieve by the end of this project?

“Hardware development takes time, often more than people expect. The NXTGEN programme gives us the space to develop over six years, which is essential as we don’t expect a market-ready product for another four years. Continuity is crucial because hardware cannot simply be launched and recalled if it doesn’t work. Thanks to NXTGEN, we have the time and space to thoroughly develop our technologies and ultimately deliver a market-ready product.”

What’s the best piece of advice you’ve received in your career?

“I can’t pinpoint one specific piece of advice, but I’ve learned a lot by observing other entrepreneurs. Collaborating with colleagues in other markets and sectors helps to understand what works and what doesn’t. For our company, for example, our technical expert Jan van Kranendonk was inspired by a lecture from Steven Chu. Learning from others and sharing knowledge is especially valuable. Additionally, focus and perseverance are crucial factors in successfully scaling up hardware ventures.”