SCIENCE-ENVIRONMENT: Drive South In A Car Running On Corn Syrup

By IPS Correspondents Reprint | | Print |

Judith Perera

LONDON, Nov 5 1996 (IPS) - Hydrogen has long been considered as a near perfect answer to the problem of matching global fuel needs with environmental demands. When it burns it produces only water vapour.

The catch so far has always been its production cost. Hydrogen is generally made by splitting water molecules, mainly by electrolysis, but this method is expensive and itself requires energy.

Now U.S. and British scientists have found a way to make hydrogen fuel from glucose sugar. The process uses enzymes, drawn from recently discovered bacteria that live deep under the sea near boiling volcanic vents on the ocean bed.

These enzymes convert glucose into hydrogen and water. The project is the brainchild of Dr Jonathan Woodward of the Oak Ridge National Laboratory in Tennessee, which is run by Lockheed Martin Energy Research Corporation for the U.S. Department of Energy.

Having succeeded in producing hydrogen on a laboratory scale using this method he is now asking the Department of Energy for a grant to build a semi-industrial scale facility. “Hydrogen is the fuel of the 21st century,” says Woodward. “The ultimate goal is to convert renewable resources into hydrogen gas.”

The experiment used glucose, a simple substance composed of hydrogen, oxygen and carbon. It was oxidised with enzymes to produce molecular hydrogen. One of the enzymes, glucose hydrogenase, takes hydrogen atoms from the glucose and transfers them to a carrier.

Then a second enzyme takes the hydrogen from the carrier to produce hydrogen gas. The system produces one hydrogen molecule for every molecule of glucose.

The key to the success of the new process is the special enzymes used which have been isolated from bacteria only recently discovered that live in extreme conditions — so called extremophilic organisms.

The extremophiles are almost alien life forms. Unlike plants, they draw their energy from chemicals, not the sun, existing at the bottom of the deep ocean in totally dark, highly-pressurised, hot and hostile environments. One exists on poisonous hydrogen sulphide and another thrives in water heated by seabed volcanic activity to 235 degrees fahrenheit, prevented from boiling only by the massive pressure of the deep seas above.

This part of the work was undertaken by Michael Danson and his colleagues at Bath University’s Centre for Extremophilic Research in Britain.

Previous attempts to develop hydrogen production using enyzmes have not been very successful because most normal enzymes do not operate efficiently at high temperatures, explains Danson.

But the enzymes from the extremophilic bacteria have no problem with high temperatures. “If you run a process at high temperatures, the reactions go more quickly, you don’t get a problem with contamination and the whole process is extremely efficient.”

For industrial scale production the process could use corn syrup — a cheap product which costs only eight U.S. cents a pound. Other possible sources of glucose are starch, lactose or simple cellulose — all cheap and readily available.

Danson says the process could even use waste paper as the raw material. Some 16 billion pounds of waste paper a year is generated in the U.S. alone — this would provide enough energy to run 37 cities the size of Oak Ridge, says Woodward.

It could also provide fuel for transport. “We are certainly aiming to generate hydrogen as a fuel for vehicles in the 21st century,” he says.

Vancouver-based Ballard Power Systems have already designed and built hydrogen powered fuel cells that have led to test vehicles being produced by Germany’s Daimler-Benz, General Motors of the U.S. and Japan’s Honda Motor Company.

The threat to the climate posed by failure to develop and exploit clean fuels is well documented. Last year the Intergovernmental Panel on Climate Change (IPCC) forecast an average global temperature increase of 3.6 degrees Fahrenheit in the next hundred years — the most rapid warming trend in 10,000 years and led largely by burning of fossil fuels like oil and coal.

By the end of the twenty-first century, the IPCC predicts that melting glaciers and thermal expansion of the ocean could produce a rise in sea level worldwide of 0.5 to 1.0 metres, triggering massive meteorological upheaval and flooding world wide.

The Chicago Transit Authority already operates three Ballard hydrogen powered buses and Vancouver has run them since 1993. A new test vehicle can carry 75 passengers 560 kilometres between hydrogen fill-ups. But presently they cost four times the price of a regular diesel bus and hydrogen as fuel is now 20 percent more expensive than petrol.

It also leaks and burns easily — the destruction of the airship Hindenburg in 1938 is history’s testament to hydrogen’s volatility. But plans to supply hydrogen safely via modified natural gas pipelines are under study. New designs for safe storage of hydrogen include absorbent tanks that hold the gas as metal hydrides.

Engineers at California’s Lawrence Livermore National Laboratory have found that tiny glass bubbles absorb hydrogen at pressures of 9,000 pounds per square inch, then release it when crushed or heated. Other novel ideas include domestic machines that would produce a day’s fuel from water drawn from the tap.

Daimler-Benz AG unveiled its prototype hydrogen powered car in May. But the difficulty of filling up with hydrogen means that the new car uses methanol, a natural gas derivative that is passed through a converter in the vehicle to hydrogen, producing some carbon dioxide as a byproduct.

Woodward’s process also produces a by-product — gluconate or gluconic acid which is used commonly in the pharmaceutical, food processing and metals industries. But this, Danson says, only makes the method even more economically attractive.

“Potentially we can take special renewable biomass or waste paper to produce a completely clean fuel,” says Danson. “It is much cheaper and simpler than splitting water to get hydrogen and is 100 percent efficient because the enzymes are 100 percent specific.” And because they are so stable, they have a long shelf life.

Work is now continuing to find the best conditions to maximise efficiency — the optimum temperature, enzyme ratios and acidity (pH) level. In the long-term, this method could revolutionise the energy industry.

Thus work is also continuing to investigate other extremophilic organisms found under the sea which might yield useful enzymes — an issue that will preoccupy the new secretariat enforcing the U.N. Convention on the Law of the Sea (UNCLOS).

UNCLOS came into force last month and its secretariat is already examining the legality of exploitation of undersea resources, many of which lie in the territorial waters of developing countries.

“I can guarantee you that the discoveries (in the deep ocean) beneficial to mankind will far outweigh those of the space program over the next couple of decades,” predicts Bruce Robinson of the Monterey Bay Aquarium Research Institute in California.

“If we can get to the abyss regularly, there will be immediate payoffs,” he says.