Blacksburg, Virginia - Scientists have dramatically increased the efficiency of producing hydrogen fuel from plant waste in a breakthrough that could one day lead to petrol stations being replaced by roadside “bioreactors” for hydrogen-powered cars.
A study has shown that it is possible to convert all the sugar stored in corn stover - the stalks, cobs and husks left over in a harvested maize field - into hydrogen gas with no overall increase in carbon dioxide emissions.
The researchers perfected the process by mixing the maize with a solution containing a cocktail of 10 enzymes that turned the plant sugars xylose and glucose into hydrogen and carbon dioxide.
Previously it has only been possible to convert up to 60 percent of the plant's sugars into hydrogen using either fermenting microbes or industrial catalysts. The latest technique converts 100 percent of the plant sugars into hydrogen.
Producing pure hydrogen gas from crop waste and biomass is seen as one of the most important goals of the green economy because of the need to find clean alternatives to petrol.
While the infrastructure to support electric cars is starting to appear in many countries, re-fuelling stations for hydrogen cars are much harder to find, due to the complexity of the science involved.
“All the products produced by the process are gases so they can be separated and collected easily from the biomass substrate. Over its lifecycle, the process is carbon neutral and we have achieved a 17-fold increase in the rate of the reaction which makes it economically viable,” said Professor Percival Zhang of Virginia Tech in Blacksburg, Virginia, who led the research, which was funded by Shell Oil.
THE MOST IMPORTANT STEP
“This means we have demonstrated the most important step toward a hydrogen economy - producing distributed and affordable green hydrogen from local biomass resources,” he said.
One of the critical developments in the process is being able to directly use “dirty” biomass as the fuel rather than relying on highly processed sugars as the source of hydrogen. In addition to being more efficient, this means it should also be possible to build large bioreactors the size of petrol stations near to sources of biomass, so leading to a network of green refuelling stations distributed around the country, Professor Zhang explained.
“I think in three to five years we should be able to build a bioreactor that is something like a gas station which can produce 200 kilos of hydrogen fuel a day. This would be enough to refuel about 40 or 50 cars,” he told The Independent.
Earlier this year car manufacturer Toyota announced that it will freely share almost 6,000 patents it owns covering hydrogen fuel cell technology, in a bid to drive development of cars that use the alternative fuel source.
The patents will be made available free to anyone wanting to use them. “When good ideas are shared, great things can happen,” said Bob Carter, senior vice president of automotive operations at Toyota.
The Independent