Fuel-cell technology has advanced steadily, yet hydrogen storage remains a significant challenge still to be met if fuel-cell vehicles are to succeed commercially. That's just one of the findings published in a recent report based on interviews with 34 fuel-cell experts throughout the world. "Three years ago, there was enormous debate about whether fuel-cell vehicles would carry hydrogen or make it on board from a liquid fuel," says Sheila Lynch, executive director of the Northeast Advanced Vehicle Consortium (NAVC), which published the report Future Wheels II: A Survey of Expert Opinion on the Future of Transportation Fuel Cells and Fuel Cell Infrastructure. "Since then, consensus has formed around carrying the hydrogen, but now the big debate is how to store enough of it on board to satisfy customer needs." The report also identifies other signs of progress -- or lack thereof -- related to fuel-cell technology. For example, it notes quick advances in the prospects of fuel cells in such applications as laptop computers and cell phones, while some experts are raising new concerns about fuel cells in the transit market. Also, the report notes that transportation fuel cells have moved from the laboratory to field trials over the past three years, resulting in an increased focus on manufacturing processes and consolidation among industry players. The complete report is available as a free download at www.navc.org. The Future Wheels II report was funded by the Defense Department's Defense Advanced Research Projects Agency. Boston-based NAVC is a public-private partnership of organizations working to promote advanced vehicle technologies in the northeast United States. It was established in 1993.