Plasma promises ultra low-carbon hydrogen production

Scientists at Manchester University are working on a new means of producing hydrogen that they claim could reduce the energy required to produce the gas by a factor of 10, potentially paving the way for a cost-effective and energy-efficient means of powering fuel cells.

The research – which forms part of a new £5m project to develop new techniques for producing, storing and distributing hydrogen funded by the UK Research Councils’ SUPERGEN programme and involving 13 universities across the country – is to investigate a process known as plasma reforming, which scientists believe could slash the temperatures required to produce hydrogen.

Currently, most hydrogen is produced using a process called steam reforming, which applies catalysts to a mixture of methane and steam at high pressures and at temperatures of between 800 and 1,000 degrees centigrade.

Achieving such temperatures requires high levels of energy and as a result the carbon savings associated with zero-emission fuel cells are typically partially offset by the energy it takes to produce hydrogen in the first place.

However, Professor Christopher Whitehead, who will lead Manchester University's research effort, insisted that the plasma-reforming process could help cut the carbon footprint associated with hydrogen production by up to 90 per cent.

Plasmas are partially ionized gases that are electrically conductive. Whitehead explained that adding an electrical discharge to the plasma initiates the reaction required to remove hydrogen from methane at relatively low temperatures, improving the energy efficiency of the process.

"Any process that can bring down the operating temperature will have big advantages, and we think using plasma could bring it down from more than 800 degrees to about 100 degrees," he said.

The process has been pioneered on a small scale to remove pollutants from gas flue pipes, but Whitehead is confident that a technically feasible version of the process for producing hydrogen from methane could be developed within five years.

He added that the technology would be highly scalable, potentially helping to address the hydrogen distribution problems that experts believe will represent the biggest stumbling block to mainstream adoption of fuel cells.

"Because you can simply turn the process on and off, it could feasibly be used in small-scale generators in people's homes where you turn natural gas into hydrogen overnight for use in their cars," Whitehead predicted.

While this process would still result in some carbon emissions, Whitehead argued that plasma reforming could also form part of a truly carbon-neutral hydrogen production process where the energy used to drive the technology is generated from renewable sources and the captured methane is taken from landfill sites.

The research is to be undertaken as just one part of a wider project involving scientists and economists from 13 UK universities and 12 industrial partners, and dedicated to lowering the cost and energy efficiency of hydrogen production.

Other research teams are expected to explore how hydrogen and associated by-products can be converted into alternative industrial feedstocks and fuels, the economic viability of hydrogen production and the policy measures required to help build a hydrogen economy.

"Fuel cells are already pretty good, so the problem now is hydrogen production," explained Whitehead. "If hydrogen is to take off, we need more efficient and cost-effective ways of producing and distributing the gas and that is what this project will address."