Hydrogen economy

A hydrogen economy is an economy in which the primary source of stored energy for mobile applications and load balancing is hydrogen. This may be gaseous, cryogenic liquid, or bound to other materials as hydrides. This is contrasted to the current world fossil fuel economy, which exploits geologic stores of coal, petroleum (crude oil), or methane (natural gas). These hydrocarbons can be readily transported and stored anyplace they are needed. Hydrogen is viewed as a replacement due to its abundance in nature, high energy density as well as its ability to be transported and stored. The drawback is the large energy source required to produce the hydrogen gas most likely by the hydrolysis of water. When the hydrogen gas is oxidized by oxygen it returns to water completing the hydrogen cycle.

Hydrogen is of particular interest for several reasons:

• When combusted with oxygen the primary product is water vapor. If combusted with air there may be small amounts of various oxides of nitrogen, called NOx, which may be destroyed with a catalytic converter. Also if methyl mercaptan or ethyl mercaptan is used for detection as in natural gas, sulfer compound contamination will occur. In addition the small size of the hydrogen molecule allows it to interact with metals causing an effect known as hydrogen embrittlement.
• When consumed in a fuel cell, electricity is produced at a high efficiency and no polution is produced - only water.
• Using electricity, hydrogen may be produced by electrolysis (electrolitic decomposition) of water, forming an energy store for electricity produced by photovoltaic solar and wind turbine energy sources.

The North Atlantic island country of Iceland has committed to becoming the world's first hydrogen economy. At present, Iceland imports petroleum products to power its fishing fleet. Iceland is located at the northern end of the Mid-Atlantic Ridge, a place of upwelling hot magma. This heat can be exploiited as geothermal energy by injecting water into deep wells into hot subsurface areas and extracting pressurized steam through other wells. The steam is used to drive turbines, which in turn drive electrical generators. While this can readilly power households, industry, and businesses, without means of storage it cannot be used for transportation other than in special cases. Hydrogen in its various forms is expected to provide that needed storage.

Several domestic US automobile manufactures have also "committed" to develop vehicles using hydrogen. (They had previously commited to producing electric vehicles in California, a program now defunct at their behest.) It is likely that the hydrogen would be obtained from coal or natural gas, with lower net system efficiencies and producing far greater greenhouse gases than would the direct use of natural gas for transportation. Critics argue this "commitment" is merely a ploy to sidestep current calls for increased efficiency in gasoline and diesel fuel powered vehicles.