Researchers have devised a method for converting carbon dioxide into clean, long-lasting fuels that produces no undesired by-products or waste. The University of Cambridge researchers previously demonstrated that biological catalysts, such as enzymes, can manufacture clean fuels from renewable energy sources, although at a low efficiency. In a laboratory setting, their latest breakthrough increased fuel production efficiency by 18 times, indicating that damaging carbon emissions may be efficiently converted into green fuels without wasting energy.
Most CO2 to fuel conversion processes yield undesirable by-products such as hydrogen. Scientists can change the chemical conditions to limit hydrogen formation, but this affects CO2 conversion performance, resulting in cleaner fuel at the expense of efficiency. The proof of concept produced by Cambridge uses enzymes extracted from bacteria to power chemical reactions that transform CO2 into fuel, a process known as electrolysis. Enzymes are more efficient than other catalysts, such as gold, yet they are extremely sensitive to the chemical environment in which they are used. The enzymes break down and chemical reactions slow down if the local environment isn’t quite perfect.
Electrolysis can lead to cleaner fuels, especially cleaner hydrogen. Hydrogen may be made by splitting water with energy, resulting in the two constituent elements of hydrogen and oxygen. Heat, light, electrical energy, chemical energy, or any combination of these can be used to create this energy. Conventional hydrogen production can be classified into three “colours” based on the quantity of carbon released throughout the process. The most prevalent contemporary approach is steam reforming methane to produce “grey” hydrogen while also emitting carbon dioxide into the environment. Carbon Capture and Storage (CCS) sequesters the carbon dioxide produced by steam reforming, resulting in “blue” hydrogen.
Electrolysis has its origins in electrochemistry investigations from the nineteenth century. Electrolysers have been created during the last 100 years and can be divided into three types: alkaline water electrolysis (AWE), polymer electrolyte membrane water electrolysis (PEMWE), and high temperature Solid Oxide Electrolysis Cell (SOEC). AWE is the most advanced of these technologies, with large commercial units available and demonstrations of units up to 100MW. They do, however, have efficiency issues and poor start/stop dynamics, making them challenging to connect to renewable energy sources.
Regarding upcoming plans, TNO is collaborating with firms and institutions in the Netherlands and internationally on the design of a Gigawatt Elektrolyser, which is expected to be completed by 2030. The Hydrohub, an open research institute in Groningen, is partnering with thirteen partners, including the Institute for Sustainable Process Technology (ISPT) and TNO, to optimise and scale up electrolysis. TNO is intimately involved in the EU project H2FUTURE, where a six megawatt PEM electrolysis unit has been placed at an Austrian steel business as a demonstration project.
TNO’s Faraday laboratory in Petten is Europe’s largest hydrogen research facility, where technological advances for upscaling are being worked on. The Hydrohub in Groningen, as well as enterprises in the supply chain, work closely together to test and develop materials and components. They are not required to invest in their own testing facilities. Faraday is an open innovation lab dedicated to improving electrolysis technologies at low and high temperatures (PEM, alkaline, AEM).
In conclusion, electrolysis technologies clearly have a role to play in any decarbonized energy system. However, if we are to accomplish some of the proposed lofty targets, a significant amount of effort will be required to even approach them. To decarbonize heavy transport in Europe, it is projected that 1600 gigawatts of electrolysis will be required, which translates to several terawatts when extrapolated to the entire world. The demand for low-cost, high-efficiency electrolysers to manufacture green hydrogen is a fertile field of study that is poised to become a major issue for the world’s research and development community.