Wednesday, March 9, 2005

GM touts fuel cell storage advance

Research partners bridge key obstacle in efforts to store the fuel in a solid state.

By Ed Garsten / The Detroit News

HRL Laboratories GM owns 33 percent of HRL Laboratories. Next, they will attack the temperature problem of storing hydrogen. Comment on this story Send this story to a friend Get Home Delivery

MALIBU, Calif. -- General Motors Corp. and its research partners have come up with a breakthrough in hydrogen storage that they say could help overcome a key obstacle to bringing non-polluting fuel cell vehicles to market.

The automaker and HRL Laboratories said Tuesday a class of chemicals called metal hydrides is capable of holding plentiful supplies of hydrogen in a solid state. The development is an important step toward safely storing enough hydrogen on a fuel cell vehicle to give it the same or better driving range than conventional vehicles.

Extremely high temperatures are needed to extract hydrogen from metal hydride, but the amount of energy required to store and release the hydrogen, as well as the weight of the metal hydride, have remained obstacles.

By storing hydrogen in a solid state rather than as a liquid or compressed gas, fuel tanks holding the extremely flammable gas could be built lighter and less expensively since the powdery chemical could be stored at lower pressures, said James Spearot, director of GM chemical and environmental sciences laboratory.

"Hydrogen storage is a very difficult challenge," said Spearot, "but one that we're making tremendous progress on."

The discovery is a first in the development of hydrogen fuel cells.

"Now we have a route to attack the temperature problem, which has never been done before," said Leslie Momoda, director of materials and sensors at HRL Laboratories. GM, Boeing Co. and Raytheon own a third of the lab each.

A fuel cell vehicle operates on hydrogen, which is converted into electricity used to power its motors. The only emission from a fuel cell vehicle powered by pure hydrogen is water vapor.

Larry Burns, GM vice president of research and development, says the automaker will have a fuel cell propulsion system in place by 2010, along with a hydrogen storage system, designed and validated to compete with the internal combustion engine on both cost and performance.

Burns said he would be disappointed if fuel cell vehicles weren't widely available by the middle of the next decade.

At Sandia National Laboratory in Livermore, Calif., independent research is being carried out in developing new metal hydrides and other materials that will hold more hydrogen and release it at lower temperatures.

GM and Sandia are working on tanks that will hold hydrogen storage material that are lighter, more efficient and less expensive than current tanks.

Compressed hydrogen tanks are made from a strong but lightweight material such as carbon fiber. The tanks carry about 5,000 pounds per square inch of hydrogen, but the goal is 10,000 psi to improve vehicle range. And for safety purposes, the tank must have a "burst strength" at least twice the pressure of the fuel. To date, tanks have been made from materials that are either very heavy or very expensive. The tanks have also been quite large, creating packaging problems in the vehicles.

The U.S. Department of Energy has budgeted $225 million this year and has requested $260 million in 2006 for fuel cell research, said Sunita Satyapal, the agency's hydrogen storage team leader.

The National Hydrogen Storage Project is aimed at complementing private industry's efforts in part by providing standardized third-party testing, said Satyapal.

You can reach Ed Garsten at (313) 223-3217 or egarsten@detnews.com.