Green Wombat

photo: PNNL
Will the car of the future be powered by hydrogen pellets? Scientists at the U.S. Department of Energy’s Pacific Northwest National Laboratory in Richland, Washington, are investigating the feasibility of using the chemical compound ammonia borane to store hydrogen. When heated, ammonia borane releases hydrogen gas that could, theoretically, be used in automotive fuel cells. PNNL scientists say an ammonia borane pellet weighing three-quarters of a gram can contain as much as 1.8 liters of hydrogen (for the metrically challenged, that’s about half a gallon). The range of fuel-cell cars currently under development by Ford (F), General Motors (GM), Honda (HMC) and Toyota (TM) is limited by the amount of hydrogen that can be stored in bulky on-board tanks. Pop in a handful of hydrogen pellets into a small onboard reactor that would control the release of hydrogen, the thinking goes, and your fuel-cell car would have the range and performance of a conventional vehicle. "It’s somewhat hypothetical but we think it’s something potentially doable," PNNL staff scientist Donald Camaioni told Green Wombat on Thursday. Presumbably such a reactor could also be used to generate electricty for home and commercial use as well.

The research is in its earliest stages, and the prospect of a hydrogen-pellet powered car is many years away, if ever. Camaioni says he and his colleagues have managed to release hydrogen from ammonia borane in the laboratory but two big challenges need to be overcome. One is figuring out how to control the release of hydrogen from ammonia borane through varying the temperature of a reactor. The other is to develop a system that can reprocess the spent pellets for reuse. "Right now there isn’t a well known way to do that cost- effectively, he says. Of course, if a hydrogen-pellet fueled vehicle is to be a carbon-free car, a no-emissions way of powering the reactor must be found as well.