Kick-starting the hydrogen economy will require cheap ways to produce vast quantities of the gas. But rather than building a new and costly plants, societies could modify existing gas powered stations instead, say Dutch and French chemists.

It is the latest proposal in a long line aimed at solving a problem that is the main barrier to a cleaner, low-carbon, hydrogen-fuelled future. However, the new idea is not without its problems: critics say retrofitting gas plants would be inefficient, but agree that the hydrogen-generation hurdle will only be surmounted using existing fossil fuel technology.

Although cheaper fuel cells and other technology needed to convert hydrogen to power are fairly advanced, there is currently no way to cheaply generate the large quantities of hydrogen needed.

Gadi Rothenberg‘s team at the University of Amsterdam in the Netherlands, working with colleagues at the University of Lyon 1 in Villeurbanne, France, say that because energy markets are conservative, only pragmatic solutions that use the existing fossil-fuel infrastructure are likely to succeed.


So the team has developed a catalyst it says could be placed in the combustion chamber of a methane-burning power plant which would allow it to produce hydrogen with little modification.

Coke problem

The researchers tested the cerium oxide and nickel catalyst using a mixture of methane and oxygen at 400 to 550 °C to simulate conditions in a power station.

Initially the methane burns up all of the oxygen present to generate heat. This allows the catalyst to break down the remaining methane into solid carbon and hydrogen gas. Two molecules of methane, containing eight hydrogen atoms between them, will yield roughly one molecule of H 2 – this gives an effective hydrogen yield of 25 to 30 per cent from the chemical process.

In a power plant, some of the heat produced could also be used to drive power generation in the usual way, claiming back lost energy and increase overall efficiency.

Tests showed that the catalyst remains active for seven hours before it becomes choked up with solid carbon. Those coke deposits can easily be burned off to clean up the catalyst, says Jurriaan Beckers, a member of the research team.

Altering the mix of gas and air in the combustion chamber also provides a way to cut coke deposits, Beckers told New Scientist, although he adds that the researchers are unsure if they could achieve this level of control in a gas power plant.

That uncertainty prompts Andrew Harris at the University of Sydney, Australia, to question whether the new process really can be integrated efficiently into existing power plants.

Gas guzzling

Harris points out that around 95 per cent of the world’s hydrogen is already sourced from natural gas, using fossil fuel reformers that react methane with steam to produce hydrogen and carbon dioxide. That process – usually 65 to 75 per cent efficient – should be sufficient to plug the gap until renewable sources of hydrogen become available, he says.

But Aldo Steinfeld at the Swiss Federal Institute of Technology, Zürich, is unconvinced. Fuel must be burned to generate the steam needed, he points out.

By comparison, gas power stations extract energy from gas more efficiently, he says. “The production of hydrogen from methane in converters will generate higher CO 2 emissions per kilowatt hour since [hydrogen production] is an energy-intensive process.”

Solar solution

Steinfeld’s own research suggests concentrated solar energy could provide the necessary heat to break down methane and produce hydrogen (Solar Energy, DOI: 10.1016/j.solener.2005.06.007).

“These hybrid processes where we “mix” solar energy and fossil fuel energy create a link between today’s fossil-fuel-based technology and tomorrow’s solar chemical technology,” he says. “It conserves fossil fuels, reduces CO 2 emissions, and offers a transition path to solar hydrogen.”

But like other ideas, for example using bacterial enzymes to generate hydrogen, the process is still only at a proof-of-principle stage. It seems likely that even more novel proposals for ways to sustainably produce hydrogen in large volumes can be expected in coming years before a solution is finally found.

Journal reference: Green Chemistry (DOI: 10.1039/b900516a)