The Storage of Hydrogen
Any energy storage for automotive applications [fuel] becomes difficult relative to fossil fuels like petrol, because of the fact that a fuel like petrol is so energy dense. Even when a typical combustion engine[15%-19% efficient] can afford to waste 80% of its energy to heat generation, still a car can travel ~300 miles plus with the petrol in the tank.
Hydrogen storage is a powerful enabling technology for PEM fuel cell usage and applications. At the moment hydrogen can be safely stored at ~10,000psi , stored in metal hydride cylinders where hydrogen is sponged up , new absorption materials discovered in Japan in August 2003, and recently in Feb 2004 a new material from Korea which is half as heavy as lithium and stores hydrogen at relatively low pressure.
Whilst the high pressure storage of hydrogen is energy intensive it is by no means crippling. The energy required is logarithmic and compression costs can in part be returned through a turbo-expander prior to fuel cell inlet. High pressure storage easily withstands the "bullet test", are lightweight and made out of super strength carbon fiber composites. Low pressure storage with these new materials discovered in Japan and Korea of late are very exciting, and should see commercial applications within 12 months. These discoveries clearly show the rate of investment and the strength of desire for hydrogen storage devices. As well the direction and timing is clear that within several years the low pressure storage of hydrogen will be conquered. I have said this continuously with confidence through year 2003.
Chemical storage like sodium borohydride is another chemical rich in hydrogen like methanol. Sodium borohydride is as energy dense as petrol from initial reports, and is of course a liquid and can be supplied as such. Hydrogen is produced on demand when the solution is passed through a catalyst releasing pure hydrogen. Sodium borohydride is made from common borax, and after use the borax returns for processing. Sodium borohydride has much potential but at the moment the costs of its production have to be reduced. Its now time applications though can be portable and micro-applications for such fuel cells. As the production of sodium borohydride becomes much cheaper, its applications as a hydrogen supply source would then go to much larger stationary applications to auto fuel cells for cars and buses. Ammonia is another chemical which is high in hydrogen density per molecule. Ammonia whilst toxic and dangerous is a liquid and can easily be applied where ammonia supply is readily available say by rail. Hydrogen generation from ammonia is not new and is highly achievable. Fuel cell locomotion is desirable as ammonia is transported by rail frequently. New liquids chemically rich in hydrogen are sure to be developed as we approach year 2010.
Australia's Natural Advantages :
Australia has the advantage of strategic location and hydrogen supply to niche markets. These markets will materialize over the next couple of years from Asia. A 26 million scooter market and light three(3) wheel vehicles markets of Asia and India exist today. Naturally such large markets will need very stable infrastructure on the supply , storage and dispensation of hydrogen as a energy carrier. Equally the fuel cell companies lobbying for such markets now have their own hydrogen storage systems involved with either metal hydride storage or a form of, or compressed hydrogen. As the fuel cell may just exceed 1Kw to 2-3 kWs for a scooter or three wheeler, sodium borohydride liquid systems would be just out of reach initially due to cost, yet with improvements could present a strong show in this market by year 2010.
Obviously the supply and dispensation of hydrogen so dependent infrastructually, must be preserved at all times as it will be of course the new fuel relied upon. Filling cylinders in advance then exporting such is an option using a canister system negates the user countries needing elaborate infrastructure. Simple replacement standardized and safe canisters to suit the scooters and three wheel vehicles can be done with relative ease.
Hydrogen storage thus is an imperative first up requirement for Australia to harness fully. Apart from the obvious niche markets as above, hydrogen storage has direct implications for Australia, due to Australia's size. Hydrogen production from fossil reformation and renewable energy like the tidal energy of Western Australia will not be done in large volumes unless obviously there are markets and contracts signed. Yet small strategic production can be done to satisfy the markets as above.
There is little doubt Australia will be exporting hydrogen as an energy carrier into canisters or to places for processing by year 2012,for the markets as above.
Stephen Zorbas
References used:
"Twenty Hydrogen Myths" by Physicist Amory Lovins of the Rocky Mountains Institute (RMI)