Electricity from Hydrogen

Electricity can be produced simply by the reaction of hydrogen and oxygen in a fuel cell.  It is essentially the reverse of the process of electrolytic production of hydrogen from water.  Fuel cells permit direct conversion of chemical energy into electrical energy resulting in practical efficiencies of between 60 and 70%.  This compares very favourably with the generation of electrical energy by means of heat engines; the primary chemical energy must be converted several times.  Each conversion results in losses so that typical efficiencies for this system lies in the region of 15 to 30%.

 

Fuel Cell

Chemical Energy           Electrical Energy

 

Heat Engine

Chemical energy           Heat Energy           Mechanical Work            Electrical Energy

 

There are many different types of fuel cells all of which operate using the same basic principle but which vary depending on the type of fuel, type of oxidant, ion conducted through the electrolyte and temperature of operation.  There is growing commercial interest in the development of such fuel cells for domestic purposes.  For instance the Swiss company Sulzer Hexis hope to have a domestic solid oxide fuel cell on the market in 2001, this will convert natural gas or hydrogen directly into electrical power (1kW).  It will also produce about 3 kW of thermal power; an auxiliary burner will supply any heat required in excess of this.