Hydrogen is the most abundant element in the universe. Hydrogen is an energy carrier - it contains the energy that powers the sun which sustains all life on earth, and hydrogen is found in all living organisms.
Hydrogen is the first element in the periodic table. It is the lightest and simplest element, and each hydrogen atom contains just one proton and one electron. Hydrogen has the highest energy content of any common fuel by weight, but the lowest energy content by volume, and as a result innovative Fuel Storage technologies are required to store pure hydrogen in comparable quantities to fossil fuels. Hydrogen combines readily with other elements and it is not found on earth in its pure form. When combined with oxygen the result is water, and when combined with carbon - hydrocarbon fuels - such as ethanol, gasoline, and coal.
Hydrogen is a fuel which can be used power Hydrogen Internal Combustion Engines and Fuel Cells. When hydrogen is combined with oxygen in a fuel cell, electricity is produced, and the two elements combine to form water in an exothermic reaction (i.e. heat is produced). The water is then usually emitted as a waste product, although in some fuel cell systems the water is recycled or utilised before being emitted.
All fuel cells other than Molten Carbonate Fuel Cells (MCFC) can run directly on pure hydrogen, however PEM fuel cells and Alkaline Fuel Cells (AFC) can only run on very pure hydrogen. As hydrogen is only found combined with other elements, it needs to be separated from them in order to be useful as a fuel for fuel cells. Hydrogen Production methods include:
- Electrolysis - separating water into hydrogen and oxygen
- Reforming - Separating hydrogen from gaseous and liquid hydrocarbon fuels
- Gasification & Purification - Gasifying organic and plastics materials into synthetic hydrogen-rich gases
- Anaerobic Digestion - Biological conversion of hydrocarbons in the absence of oxygen - usually by bacteria
- Fermentation - Biological conversion of hydrocarbons, usually by bacteria or yeasts
- Algae - certain algae emit hydrogen as a waste product from their metabolism
If the electricity used to drive the electrolysis process is derived from Renewable / Alternative Energy Sources, the resulting hydrogen can be called ‘renewable hydrogen’, and therefore carbon-neutral, thus not contributing to the greenhouse effect and resulting global warming. Renewable hydrogen can also be produced from gasifying biomass and other materials that do not contribute to increasing overall carbon levels in the atmosphere.
|
