Reverse combustion

What if carbon dioxide could itself be turned into a fuel? Such a neat solution for the waste gas that’s causing climate change may be just round the corner, because German start-up INERATEC has developed a chemical process to do just that.

“We’re reversing the combustion process,” explains Tim Boeltken, INERATEC’s chief executive. “The chemical process we’ve created takes the greenhouse gas CO₂ that nobody wants and combines it with green hydrogen to create a synthetic hydrocarbon fuel.”

INERATEC’s method could reduce emissions in a number of sectors that have few clean alternatives, including aviation, which accounts for a growing share of global greenhouse gas emissions. The company already has clients in the aviation, shipping and chemicals industries, but to demonstrate its technology at a larger scale, it is building a facility near Frankfurt airport with the backing of a €40 million venture debt loan from the European Investment Bank. The deal is supported by the European Union’s InvestEU programme and includes a €30 million grant from Breakthrough Energy Catalyst, a financing platform for climate innovation founded by Bill Gates.

“The aviation industry is struggling to decarbonize,” says Stephan Mitrakas, a senior loan officer who worked on the deal at the European Investment Bank. “Alternatives to jet fuel, such as electricity and hydrogen, both have major drawbacks and would require the development of a completely new infrastructure set up for transport, storage and fueling.”

“The beauty of synthetic fuels is that you can keep the infrastructure we already have,” Mitrakas adds. “You can take the synthetic fuel from INERATEC, mix it in with the kerosene that planes currently use, and the aeroplane will work. INERATEC is the most promising start-up in the field right now, certainly in Europe and probably in the world.”

The German company, spun out of the Karlsruhe Institute of Technology in 2016, has attracted an impressive list of investors, including the French aviation engine maker Safran, Japan’s Honda, the US venture capital firm PIVA Capital Partners, the venture capital arm of the French power utility Engie, the German venture capital fund High-Tech Grunderfonds, and the Karlsruhe Institute of Technology itself.

Located at Industrial Park Höchst, one of the largest research and production sites for the chemical and pharmaceutical industry in Europe, the new facility will produce up to 2 500 tons of sustainable synthetic fuels a year. That will make it the largest production site for sustainable synthetic fuels in the world. The site offers unique advantages for INERATEC, including the supply of hydrogen released as a byproduct from a chlorine plant and CO₂ from a biogas plant, both located in the industrial park. There's also a supply of green electricity. The demonstration facility will produce synthetic crude, which will then be refined onsite into ready-to-use sustainable aviation fuel.

“This is a steppingstone for the global rollout of climate technologies made in Europe that can be deployed anywhere in the world where you have access to cheap green electricity and CO₂ emissions,” says INERATEC’s Boeltken.

The new facility will give INERATEC the chance to demonstrate its highly efficient modular reactor system at a larger scale. The company's groundbreaking technology uses compact chemical reactors that are 80 times smaller than conventional systems. These reactors contain micro tubes filled with catalysts that enable highly controlled chemical reactions. These reactions convert the hydrogen and CO₂ into the synthetic crude oil that's then refined into aviation fuel and other products for the chemical and food industries.

INERATEC's production plants are modular and can be transported by truck. The plant modules can be manufactured in standard formats suitable for serial production, unlike traditional chemical plants that require custom engineering. Operators can start with standard units and expand capacity over time by adding more modules.

Another benefit is rapid start-up and shutdown times, making the technology well-suited for use with intermittent renewable energy such as wind and solar power. The plants can be deployed wherever low-cost renewable electricity and sustainable CO₂ are available.

Demand for synthetic aviation fuel is driven by the European Union’s decarbonization targets for its economy. The European Union’s ReFuelEU Aviation regulation requires that aviation fuel suppliers provide jet-fuel with 1.2% minimum synthetic fuel content by 2030, an obligation that rises to 35% by 2050.

“Europe has really kick-started this market,” says Boeltken, the chief executive. “The US followed but is now making a 180-degree turnaround. It’s a huge chance for Europe to really become a champion in this climate technology sector, but it’s evident that a clear long-term regulatory framework is absolutely vital.”