Hydrogen Economy

A scenario where the world uses hydrogen as the primary energy carrier in place of fossil fuels.

Note: Fossil fuels are an energy carrier, but they were produced over a time scale of a few hundreds of millions of years and so it is not quite correct to compare this to hydrogen as an energy vector.

Hydrogen would be used to provide electrical power, heat homes and power vehicles. Ideally this hydrogen would be generated from renewable energy, resulting in zero emissions.

Hydrogen is not a source of energy. It is only a way of storing and transporting it. Although hydrogen is the most abundant element in the Universe (and in the more immediate neighbourhood, it makes up 90 percent of the atoms in the Sun and Jupiter), there is virtually no hydrogen gas on Earth. Our gravity is so weak that essentially all our primordial hydrogen, except that which bound itself into heavier compounds, escaped into space billions of years ago.

Hydrogen fuel must be "manufactured" by extracting it from water and methane. You get out from hydrogen fuel only the energy you put into extraction, or from burning carbon in the process.

Water can be split into hydrogen and oxygen by electric current, the process known as electrolysis. Plain heat will do the trick too. Above 2700°C water spontaneously decomposes. On a sufficiently hot fire, water decomposes and then recombines when it cools.

Splitting water is expensive, and the oxygen is not required. A much cheaper way to produce hydrogen is to spray steam on white-hot coals. This results in mostly hydrogen gas (40 percent) and carbon monoxide (50 percent), a mixture known appropriately as "water gas." It′s the least expensive way to make hydrogen. Unfortunately, the carbon monoxide produced along with it is highly poisonous. To extract the last bit of energy, the carbon monoxide can be burned, and that turns it into the greenhouse gas carbon dioxide.


See also: Fuel Cell, Hydrogen.

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Subjects: Automotive Transport


Weblinks:
Fuel Cell and Hydrogen Energy Association The world′s premier advocacy organization dedicated to the commercialization of fuel cells and hydrogen energy technologies.
Fuel Cells and Hydrogen - Joint Undertaking Public private partnership supporting research, technological development and demonstration (RTD) activities in fuel cell and hydrogen energy technologies in Europe.