The following options for generation or release of hydrogen for portable polymer electrolyte fuel cells have been studied:
1. pressurised gas (reference)
2. metal hydride storage
3. reaction of metal hydrides with water
4. ammonia cracking
5. methanol reforming by partial oxidation.
For each of these five options energy content, System weight and cost of hydrogen or electricity have been determined for conversion Systems equipped with an assumed storage volume of one litre. The cost analysis includes labour and administrative expenses. For the first three options only the best of the analysed cases is presented here. An electrical PEFC-efficiency of 50% was assumed in the last column, but the cost of the fuel cell itself were not considered. The electric power generated with polymer electrolyte fuel cells and hydrogen from portable sources is over 1'000 times more expensive than grid power electricity, but less costly than power from small batteries. Ordinary lead acid batteries offer slight cost advantages, but the low power density of only 0,03 kWh/kg makes them inconvénient for many practical applications. An attractive source of hydrogen appears to be reaction of alkali métal hydrides with water. The Chemical reactor is small, light and low in cost. Furthermore, by this method hydrogen and electricity can be provided at acceptable prices.
