Combustion Reaction of Hydrogen

Hydrogen and Combustion

Hydrogen gas (H2) is an alternative fuel that burns in oxygen.
The combustion reaction of hydrogen gas can be described by the balanced chemical equation: 2H2(g) + O2(g) –> 2H2O(g).
This means two molecules of hydrogen gas react with one molecule of oxygen gas to produce two molecules of water vapour.
It’s important to note that the combustion of hydrogen is an exothermic reaction, meaning that it releases heat.
This released heat is used to generate steam for power generation in a hydrogen power plant, or directly to power a fuel cell in a hydrogen-powered vehicle.

Hydrogen contains a high energy content per unit mass. This is about 2.8 times higher than hydrocarbon fuels, though its energy content per unit volume is lower.
Hydrogen is a carbon-free fuel. When burned in air, the only by-products are heat and water vapour, making it a clean source of energy that doesn’t contribute to carbon dioxide emissions.
Being light and highly diffusive, hydrogen is often present in a gaseous state. This makes it less likely to cause contamination in the case of a leak.

Hydrogen is a flammable gas. Mixtures of hydrogen and air can be explosive, meaning it’s crucial to handle it with proper safety measures.
Hydrogen gas is odourless and colourless. This means leakages can be difficult to detect without the use of special sensors.

Although hydrogen combustion is clean, producing hydrogen itself often relies on energy from fossil fuels which can cause pollution. For hydrogen to be a truly sustainable fuel, all aspects of its life cycle should be green.
Green Hydrogen can be produced using renewable energy (like solar and wind power) to split water into hydrogen and oxygen—a process called electrolysis. This form of hydrogen production has no carbon emissions and is environmentally friendly.
Hydrogen as a fuel is not only used for combustion in engines but can be used in a fuel cell to generate electricity with only water as the by-product.
Its storage and transport require special considerations due to its density and reactivity. Getting hydrogen to gas stations for fuel cell vehicles, for instance, involves significant hurdles.