1.   An American scientist has invented a fuel cell which he claims can store hydrogen safely, thus making possible its commercial use as a power source.

2.   Among the problems, a practical technology for storing hydrogen in the quantities needed for a vehicle has yet to be invented.

3.   This made it easier to store the hydrogen, but also made a car that was tremendously complex and costly.

4.   But concerns about storing liquid hydrogen under high pressure have stymied its use in automobiles because of the risk of explosions and fire, experts said.

5.   In addition to this alliance, the companies also are working together to develop fuel cells and the technology to store hydrogen that powers the cells.

6.   One hurdle to extending the range of a fuel cell vehicle is the ability to efficiently store compressed hydrogen at high pressure.