German researchers have invented a new technology that allows the burning of methane for energy generation without releasing any CO2 emissions.
The technology relies on what the engineers call ‘methane cracking’, a process during which hydrogen atoms and carbon atoms forming the methane (CH4) molecule are separated from each other at temperatures of more than 750°C. The products - pure hydrogen and carbon - can subsequently be processed separately: hydrogen for energy generation and the high-quality solid black carbon powder for the manufacturing of steel, carbon fibres or structural composites, for example.
Methane cracking has been studied in the past, but the technology so far has not been viable.
However, over the past two years a team at the Institute for Advanced Sustainability Studies (IASS) in Potsdam and the Karlsruhe Institute of Technology (KIT) developed a reactor capable of sustaining the methane cracking reaction, which is now able to run reliably and continuously.
“In the most recent experiments, our reactor operated without interruptions for two weeks, producing hydrogen with a 78 per cent conversion rate at temperatures of 1200°C,” said KIT Professor Thomas Wetzel.
“In particular, the continuous operation is a decisive component of the kind of reliability that would be needed for an industrial-scale reactor.”
Methane cracking, the researchers say, is a far more environmentally friendly method of hydrogen production than currently prevalent steam methane forming, which releases huge amounts of CO2.
Burning of hydrogen is perfectly clean and offers very high energy density per unit mass. Hydrogen could be used for power generation or in hydrogen-powered cars.
The team, led by Nobel Prize Laureate Carlo Rubbia, also analysed economic aspects of the technology and concluded it could achieve costs of between 1.9 and 3.3 euros per kilogram of hydrogen, at current German natural gas prices.
“Our experimental results as well as the environmental and economic assessments all point to methane cracking as a clear candidate option in our portfolio of measures to transform the energy system,” Professor Rubbia said. “This could be a gap-bridging technology, making it possible to tap into the energy potential of natural gas while safeguarding the climate and facilitating the integration of a clean energy carrier like hydrogen.”
Methane – the main component of natural gas – is a widely used fossil fuel whose worldwide production is forecast to rise dramatically in the coming decades. Despite being cleaner than coal, burning methane still adds to the intensifying global warming problem.