Author: Banister Nuri
Institution: Philosophy and Technical Communications
Date: April 2005
Researchers at the U.S. Department of Energy's Idaho National Engineering and Environmental Laboratory (DOE, INEEL) report a significant step forward in their efforts to produce hydrogen from water. Using a high temperature variant of conventional electrolysis, the team has been able to extract hydrogen from water with a roughly 20 percent boost in efficiency as compared to conventional methods. They hope that this development will one day streamline hydrogen production to help advance the nation towards a clean hydrogen-based economy.
Conventional electrolysis is the process by which an electrical current passes through water, splitting it into its oxygen and hydrogen components. Such a process has been known to exist for more than one hundred years, and is an experiment often done in high school science classes.
High-temperature electrolysis, by comparison, uses steam in place of liquid water. By using something called a solid oxide fuel cell, a device resembling a hydrogen fuel cell running in reverse, INEEL researchers significantly lowered the amount of electricity needed to split the water to extract hydrogen.
"We're using the same technology, but basically running it backwards," says lead INEEL researcher Steve Herring. "That is, applying the electricity to produce hydrogen and oxygen, rather than supplying hydrogen and oxygen to produce electricity."
Because of its higher energy content (due to its higher temperature), steam significantly lowers the energy needed to split water into hydrogen and oxygen, making it easier to produce more Hydrogen using less electricity.
"The researchers tried steam because they knew there was some energy already in steam vs. water some of that energy that's needed to break that bond," says Michael Anderson, DOE-Idaho initiative lead for the project.
To provide the amount of energy necessary to boil the water into steam, INEEL researchers are envisioning use of a still theoretical Generation IV nuclear reactor to power the hydrogen production process. Unlike current Generation I and II light-water reactors (the type most commonly used in the United States today), which produce turbine-turning steam at about 300° C, Generation IV reactors will produce steam at temperatures of roughly 1000° C. This higher temperature, in addition to upping hydrogen generating efficiency, also makes Generation IV reactors more efficient in their use of fuel.
"A lot of the reactors online today still have about 90 percent of the fuel potential in the fuel after it's been spent and can no longer be used," says Anderson.
Using more efficiently designed nuclear fuel, Generation IV reactors have the potential to dramatically increase the amount of energy derived from the fuel.
"By doing that you're getting more kilowatt generation out of that fuel before it's used and you have less waste at the end of the cycle. So you save waste disposal costs as well," Anderson says.
Generation IV reactors will also use low-enriched Uranium, according to Anderson, rather than high-enriched uranium. This lower quality material will produce a waste byproduct unfit for weapons use, thus lowering the risk that the waste will eventually become part of a nuclear bomb.
Using a Generation IV reactor to produce hydrogen is part of DOE's overall plan to provide the nation with the means to break its reliance on ever diminishing oil reserves.
"This is a way of applying nuclear energy,of applying the Uranium resources that we have,to our need for transportation fuel," says Herring.
[Press release: http://www.eurekalert.org/pub_releases/2004-12/dne-ilu120704.php]