Hydrogen from water electrolysis plant

Water is already an issue for current fossil-fueled plant construction, especially in the arid western United States. Water is also a global issue. It is apparent that generating hydrogen from water electrolysis will only exacerbate the issue. The conclusion is that water desalination plants will be necessary. If these desalination plants are placed in or near cities that currently have oil ports, then the existing liquid fuels distribution infrastructure could be used for electrolysis-grade water delivery. 

Figure 1. Estimated hydrogen production cost from a large water electrolysis plant. Electric power cost = 2.5 /kWh 90% duty cycle.

The Pacific Nitrogen Corporation plant at Seattle, Washington, is the only plant in the country now operating on hydrogen from the electrolysis of water. Although the power rate of 30 per kilowatt year is not particularly attractive for this operation, production is continued economically because of other sectional conditions. 

Industrial scale electrolyzers were developed early in the 20th century for the manufacture of chlorine and caustic soda from brine, and for the commercial production of hydrogen used in ammonia synthesis. Large water-electrolysis plants were constructed in Norway and Canada in the 1930 s, based on cheap hydroelectric power, and the hydrogen so produced was used in fertilizer manufacture. With the advent of natural gas and low cost petroleum, hydrogen production moved toward catalytic steam-reforming of hydrocarbons, and water electrolysis became less significant. 

Currently, global hydrogen production is 48% from natural gas, 30% from oil, and 18% from coal water electrolysis accounts for only 4%. The distribution of production reflects the effects of thermodynamic constraints on economic choices of the four processes for obtaining hydrogen, partial combustion of natural gas in a natural gas combined cycle power plant offers the most efficient chemical pathway and the greatest off-take of usable heat... 

These fuels (pure H2, H2/C02, and H2/C0/C02) can also be produced from renewable energy sources—biomass, solar, windmills, and hydroelectric power. On the other hand, pure H2 can be generated by water electrolysis using nuclear power plants. Hydrogen is the most electro-reactive fuel for fuel cells operating at low and intermediate temperatures. 

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