Brussels, 21 Mar 2006
Hydrogen is one energy source that could solve a number of environmental problems. As a fuel it can be burnt, and has only water as a by-product. However, finding cheap sources of hydrogen, and storing the fuel safely, are two challenges that researchers are yet to overcome.
The Hyvolution project, funded under the EU's Sixth Framework Programme (FP6), aims to produce hydrogen from biomass in an experimental plant. The project will use bacteria to digest organic matter, releasing hydrogen. The plant will be developed in Wageningen, the Netherlands, with input from 11 EU countries, Turkey and Russia.
'It is important that the economy becomes sustainable, and hydrogen can play a part in this,' says Professor Frons Stams of Wageningen University's microbiology lab. '[Arnold] Schwarzenegger already drives around in a hydrogen-powered car, and there are also experimental buses operating in Amsterdam that are powered by hydrogen from Shell. There is a need for hydrogen, and science can help. Hydrogen is definitely a clean fuel. And the energy that is released with the oxidation of hydrogen can be converted very efficiently into electricity.'
Hydrogen is not 'freely' available anywhere - it cannot be mined as natural gas can, and it cannot be extracted from the air. Hydrogen is found bound up in other molecules, such as water. Today, hydrogen tends to be 'cracked' from fossil fuels, which separates into solid carbon and hydrogen. This process is however ultimately unsustainable, the researchers from Wageningen believe.
The biomass approach will make use of materials currently considered 'waste', such as crop residues or food industry by-products, thereby reducing landfill. The plant could also use specially grown crops.
The process would work by introducing the organic material to a type of fermenting vat. Inside, special bacteria would digest the living matter, releasing hydrogen and carbon dioxide in a two-stage process. This carbon dioxide is environmentally 'neutral', however. 'Trees and plants take up CO2 and produce biomass, we harvest the biomass for the hydrogen and make CO2 as a by-product. The net result is that no extra CO2 is added to the atmosphere. The story is completely different with fossil fuels. When those are burned, CO2 that has been stored for millions of years in the ground is released into the atmosphere,' said Rene Rozendal of Wageningen University's environmental technology department.
The success of hydrogen as a fuel will come when it is seen as cost-effective. One significant problem is storage. Hydrogen is explosively inflammable, as film of the 1937 Hindenburg Zeppelin disaster shows.
The researchers see the possibility of many small-scale biomass plants, potentially hydrogen fermenters in the back-yard, reducing the need for the risky transport of the gas. Vehicles powered on hydrogen need relatively frequent re-filling: 25 cubic metres of hydrogen can power a car for only around 200 km, so current technologies would need those many, small supply depots.
Some critics disagree over the potential of the hydrogen model, as biomass could be used to produce other gases, such as methane, directly. These gases could in turn power an electricity plant. The process would still be environmentally neutral, but not require the hydrogen 'step'.
As technology drives improvements in efficiency, so the economics of hydrogen use will change, and its role in a sustainable future will also change.