Hydrogen Fuel Closer to Fruition

The raw materials — water and sunlight — are free. The only waste, oxygen, is nonpolluting. And the product is hailed as the mean, green, fuel of the future. Welcome to the hydrogen economy.

By Daithí Ó hAnluain

Story location: http://www.wired.com/news/technology/0,1282,64797,00.html

The premise is sound, but the obstacles are substantial. Hydrogen is the most abundant element in the universe. However, it is shamelessly promiscuous. It will hook up with almost any atom it passes. Like oxygen, in whose sweet embrace it produces water. Or carbon, in whose grubby grope it makes fossil fuels. It doesn’t come in a pure form.

Currently, the cost of producing hydrogen fuel is greater than the value of the energy it delivers. Production entails either electrolysis in water or extraction of hydrogen from fossil fuels like natural gas.

But as scientists worldwide race to find cheaper ways to produce hydrogen, last week teams from the United States, the United Kingdom and Australia announced some major advances.

"I think it is indisputable that it is a race because the people who develop the IP (intellectual property) that works will be the OPEC of the future," said professor Christopher Sorrel, a director of the Centre for Materials and Energy Conversion at the University of New South Wales.

Last week, Sorrel and colleagues promised advanced materials developed in their lab would lead to a commercial solar panel in seven years that would produce cheap hydrogen from water, a production method known as solar hydrogen.

Karen Brewer, who leads a team at Virginia Tech that last week announced another method to produce solar hydrogen, is less gung-ho.

"I don’t feel it’s a race, I feel that people are working hard to work together and are sharing their information very freely in terms of where they are. Certainly people are feeling the pressure to get results; everybody wants to be first," she said.

Hydrogen fuel is not a new idea. Sir William Grove invented the first hydrogen fuel cell in 1839. But interest in the technology took off in recent years to combat greenhouse gases and end oil dependence.

In the United States last year, the federal government launched a $1.2 billion Hydrogen Fuel Initiative. Major research programs also exist in Europe and Japan. But the cost of harvesting hydrogen must come down to make the fuel economically viable.

Sorrel said that’s what the University of New South Wales team did, using modified titanium oxide ceramics in a solar panel. Titanium is a popular choice in solar hydrogen research because it has the right semiconducting properties and it’s resistant to water. But it is not efficient enough on its own without modification.

Sorrel’s group identified 10 key variables that subtly alter the properties of the titanium oxide. By manipulating these variables, the team got a significant boost in performance. But the technology is still not ready for the big time. The team now needs to produce better materials by changing the variables.

"It will take five to seven years to produce a device, less if we get the resources we need," said Sorrel. "We know the extent of our ignorance; we know where we’re going. It’s just a question of running the thousands of iterative experiments."

"(They’re) optimistic, and missing some pieces of the puzzle, but that’s par for the course with these announcements," said Stephen R. Connors, director of the Analysis Group for Regional Electricity Alternatives at MIT’s Laboratory for Energy and the Environment. Connors said issues like the variability of sunlight, water purity, storage and distribution remain for all solar hydrogen projects.

Nevertheless, finding a way to use solar energy to split water is one of the most important avenues of hydrogen research.

"Sunlight is essentially an unused resource, so there’s no energy cost when you use it for hydrogen production," said Virginia Tech’s Brewer.

Brewer’s group is developing supramolecules — molecular machines created using combined molecules — to gather electrons.

It’s a good trick. Electrons normally repel each other, but Brewer’s group developed a molecular machine that can gather electrons together and deliver them to a reactive metal site where they can do their work — splitting hydrogen from water.

Solar hydrogen is not the only technology pursued by researchers. A team in the United Kingdom announced last week an experimental hydrogen generator that uses only sunflower oil, air and water vapor along with two highly specialized catalysts — one nickel-based, the other carbon-based — that are alternately used to store and then release oxygen or carbon dioxide while producing hydrogen intermittently.

The team, based at the University of Leeds’ Energy & Resources Research Institute, said in a statement that its system could be used to supply a gas station with hydrogen for distribution to motorists.

It’s further proof, Brewer said, of the importance of hydrogen research. But the emergence of a hydrogen economy is harder to predict.

"I think at this time we’re not so much knowledge-limited as we are resource-limited," said Brewer. "The time it takes to develop a hydrogen economy ultimately depends on the resources people are willing to commit."