A fuel cell is a device that converts chemical energy directly into electrical energy through an electrochemical reaction. It operates like a battery but doesn’t need recharging; it produces electricity as long as fuel is supplied.

Basic Components:

• Anode: Where hydrogen fuel is fed in.
• Cathode: Where oxygen (usually from the air) is introduced.
• Electrolyte: A substance allowing ions to move between the anode and cathode.

Electrochemical Reaction:

• Hydrogen is Split: At the anode, hydrogen molecules (H₂) are split into protons (H⁺) and electrons (e⁻).

2H2​→4H++4e−

• Electron Flow: Electrons are forced to move through an external circuit, creating an electric current that can do work (power a motor, light a bulb, etc.).
• Oxygen Reaction: At the cathode, oxygen combines with protons and electrons to form water.

O2​+4H++4e−→2H2​O

Benefits:

• Clean Energy: Only byproduct is water.
• Continuous Operation: As long as fuel (hydrogen) is supplied.
• Efficiency: Can be more efficient than traditional combustion engines.

Applications:

• Transportation: Fuel cell vehicles (FCVs).
• Stationary Power: Backup power for buildings.
• Portable Power: Portable electronic devices.

Hydrogen and Fuel Cell Technology

Hydrogen is the simplest and most abundant element in the universe. It is a major component of water, oil, natural gas, and all living matter. Despite its simplicity and abundance, hydrogen rarely occurs naturally as a gas on Earth. It is almost always combined with other elements. It can be generated from oil, natural gas, and biomass or by splitting water using renewable solar or electrical energy.

• Once hydrogen is produced as molecular hydrogen, the energy present within the molecule can be released, by reacting with oxygen to produce water. This can be achieved by either traditional internal combustion engines, or by devices called fuel cells. In a fuel cell, hydrogen energy is converted directly into electricity with high efficiency and low power losses.
• Hydrogen, therefore, is an energy carrier, which is used to move, store, and deliver energy produced from other sources.
• Hydrogen is a clean fuel that, when consumed in a fuel cell, produces only water. Hydrogen can be produced from a variety of domestic resources, such as natural gas, nuclear power, biomass, and renewable power like solar and wind. These qualities make it an attractive fuel option for transportation and electricity generation applications. It can be used in cars, in houses, for portable power, and in many more applications.

2H2​+O2​→2H2​O + energy

Different types of Hydrogen

Black, brown and grey hydrogen

Grey hydrogen is the most common form and is generated from natural gas, or methane, through a process called “steam reforming”.

• This process generates just a smaller amount of emissions than black or brown hydrogen, which uses black (bituminous) or brown (lignite) coal in the hydrogen-making process.
• Black or brown hydrogen is the most environmentally damaging as both the CO2 and carbon monoxide generated during the process are not recaptured.

Blue hydrogen

• Hydrogen is labelled blue whenever the carbon generated from steam reforming is captured and stored underground through industrial carbon capture and storage (CSS).
• Blue hydrogen is, therefore, sometimes referred to as carbon neutral as the emissions are not dispersed in the atmosphere.
• However, some argue that “low carbon” would be a more accurate description, as 10-20% of the generated carbon cannot be captured.

Green hydrogen

• Green hydrogen – also referred to as “clean hydrogen” – is produced by using clean energy from surplus renewable energy sources, such as solar or wind power, to split water into two hydrogen atoms and one oxygen atom through a process called electrolysis.
• Renewables cannot always generate energy at all hours of the day and green hydrogen production could help use the excess generated during peak cycles.
• It currently makes up about 0.1% of overall hydrogen production, but this is expected to rise as the cost of renewable energy continues to fall.
• Many sectors also now see green hydrogen as the best way of harmonizing the intermittency of renewables – storing excess energy at times of low demand to be fed back into the grid when demand rises – while decarbonizing the chemical, industrial and transportation sectors.

Pink hydrogen

• Like green hydrogen, it is created through electrolysis of water but the latter is powered by nuclear energy rather than renewables.

Yellow hydrogen

• Tt is the term used for hydrogen made through electrolysis of water using solar power

BIOLOGICAL PROCESSES

• Biological processes use microbes such as bacteria and microalgae and can produce hydrogen through biological reactions. In microbial biomass conversion, the microbes break down organic matter like biomass or wastewater to produce hydrogen, while in photobiological processes the microbes use sunlight as the energy source.