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Assuming that humanity finds a means to produce hydrogen without causing as much pollution at the point of origin as fossil-fuels do at the point of consumption, hydrogen is a very viable source of stored energy for the future. Hydrogen fuel cells combine hydrogen and oxygen to create a chemical reaction which produces electricity, with no by-products aside from water vapor. This electricity can be used to power any electrical devices, such as cell phones, laptop computers, and perhaps most importantly, electric automobiles.

Fuel cell technology is certainly not new, it was being used by NASA in the 1960s to provide electricity to space vehicles for the Apollo moon missions. The technology is proven, reliable, and efficient. But hydrogen, being gaseous, tends to occupy a lot of space. It can be pressurized to reduce its volume, but the higher the pressure, the stronger the storage tank must be; so as the volume increases, this approach quickly becomes impractical. And hydrogen is highly flammable, as the Hindenburg disaster so memorably demonstrated. So in addition to finding a clean way to produce hydrogen, there must be a safe way to transport large amounts of it in the supply chain, and in the automobiles themselves.

While still struggling with the first hurdle, there has been some interesting recent progress with the second. A team of Danish scientists have developed a tablet which can store large amounts of hydrogen safely. The hydrogen is stored in the tablet as ammonia, which is comprised of hydrogen and nitrogen atoms. When the hydrogen is needed, a catalyst is introduced, which decomposes the ammonia back into free hydrogen. The tablets can later be “refilled” by adding more ammonia.

From the news release:

“Should you drive a car 600 km using gaseous hydrogen at normal pressure, it would require a fuel tank with a size of nine cars. With our technology, the same amount of hydrogen can be stored in a normal gasoline tank”, says Professor Claus Hviid Christensen, Department of Chemistry at DTU.

News Release
Wikipedia entry on Fuel Cells
Wikipedia entry on the Hydrogen Economy