Swedish researchers have created a way of turning ash from power stations run on landfill waste into hydrogen.
The heavy, grit-like bottom ash formed by burning rubbish is often used to cover landfills or as a construction material but gradually releases hydrogen when stored so is usually kept in the open so the gas can escape in order to avoid an explosion risk.
The scientists from Lund University have a developed a technique of dampening the bottom ash with water in an oxygen-free environment to rapidly release the hydrogen, which can then be collected and stored.
‘The ash can be used as a resource through recovery of hydrogen gas instead of being allowed to be released into the air as at present,’ said Aamir Ilyas, doctor of water resources engineering at Lund University and the developer of the technique.
‘A bonus is that this method removes the risk of hydrogen gas. It also reduces the strain on our landfill sites.’
The researchers estimate that use of this technique has the potential to generate 20 billion litres of hydrogen gas a year – 56 gigawatt-hours (GWh) worth of energy.
Hydrogen is most commonly produced from natural gas or other fossil fuels but a small proportion is now manufactured from gassifying biomass or electrolysing water.
Kenneth Persson, professor of water resources engineering and one of Ilyas’s supervisors at Lund suggested this method could contribute to the more environmentally friendly generation of hydrogen.
‘There will not be one universal solution that will be used to generate energy. We need to find a number of solutions,’ he said.