When power plants burn coal, wood or even refuse to generate electricity, the leftover ash generates hydrogen gas, which is why it must be stored outside.
Leftover ash from power production often finds its way to landfills or, in some countries, as a construction material. It can’t be stored inside though, because the leftover ash generates hydrogen gas and this presents an explosion hazard.
Now that hydrogen gas is becoming a more important part of our infrastructure, researchers are looking for new ways to generate the gas. Leftover ash from power plants could be one of these sources.
For safety reasons, ash is stored outside to prevent the explosion hazard, but researchers at Lund University are looking to tap this resource and collect the hydrogen gas. Ash, when mixed with water in an oxygen-free environment, generates hydrogen gas, which can then be collected and stored.
Aamir Ilyas of Lund University estimates that Sweden’s leftover ash, about 1.5 million tons annually, could generate 706 million ft3 of hydrogen gas. This is the equivalent of 56GWh of electricity or the same amount of power needed to run 11,000 average homes.
By wetting ash and storing it in an oxygen-free environment, the hydrogen gas produced could be used as fuel for hydrogen fuel cell vehicles and backup power supplies, as well as being fed back into the combustion process to produce electricity. By using the leftover ash to generate hydrogen gas, the process also keeps the ash out of landfills where it can leech dangerous chemicals into the soil and groundwater supply.