Hydrogen Technology
A Little History
Hydrogen was discovered in 1766 by Cavendish and “named” 22 years later by Lavoisier. Industrial production and use began in 1920, with hydrogen being widely used in the form of town gas (which generally contained around 50% hydrogen). Its widespread use as an energy carrier is expected to begin during the first half of the 21st century.
The fuel cell phenomenon was scientifically discovered in 1839 by Sir William Grove, and at the end of the 19th century Ostwald proposed its use as a system for generating electricity. In 1959, Francis Bacon built the first operational fuel cell model, based on alkaline technology and with a maximum power output of 5kW. During the height of the space race, NASA developed alkaline and polymer fuel cells to generate electricity on board spacecraft, which subsequently drove their development for all kinds of applications. We are currently in a phase of accelerating development and demonstration, and widespread commercialisation and deployment are expected in the medium term.
Technology Description
Hydrogen is a diatomic, colourless and odourless gas; although it is the most abundant element in the universe, on Earth it is always found combined with other elements, such as oxygen to form water (H2O), carbon to form hydrocarbons, or other elements to form countless different compounds.
Hydrogen is a fuel that can be used directly by burning it to produce heat, as is currently done with natural gas, or it can be used electrochemically to generate electricity more efficiently. However, energy is required to separate it from molecules such as water, natural gas or others, and it is at this point that we can define what hydrogen represents from the perspective of energy systems.
Hydrogen is an energy carrier, meaning that it is a substance that stores energy so that it can subsequently be released in a controlled manner. It differs from energy sources (hydrocarbons, nuclear or renewable energy) in that its production requires a chemical or electrochemical process in which a certain amount of energy is invested, and this amount will always be greater than the energy subsequently obtained in its final application.
Other examples of energy carriers include batteries, capacitors and water stored behind a dam, although there are many other variants, such as flywheels, compressed-air storage tanks and even springs.
Hydrogen is currently used as a chemical reactant in industry, but it is expected to have a promising future as an energy carrier, since both combustion reactions and electrochemical reactions produce water as a by-product. Therefore, in principle, hydrogen offers a significant environmental advantage.
Direct combustion reaction:
H2 + O2 –> Heat + H2O
Electrochemical combustion reaction:
H2 + O2 –> Electricity + Heat + H2O
