What is Hydrogen fuel?

Hydrogen is the most abundant chemical element, estimated to contribute 75% of the mass of the universe. Hydrogen fuel refers to hydrogen which is burned as fuel with pure oxygen.

Hydrogen fuel can be a zero-carbon fuel, provided that it is created in a process that does not involve carbon. However, most hydrogen comes from fossil fuels, resulting in carbon dioxide emissions.

What are the various methods of hydrogen fuel production?

Today, hydrogen fuel can be produced through several methods. The most common methods today are natural gas reforming (a thermal process), and electrolysis. Other methods include solar-driven and biological processes.

Why hydrogen is regarded as an alternative fuel?

■ The interest in hydrogen as an alternative transportation fuel stems from its ability to power fuel cells in zero-emission vehicles, its potential for domestic production, and the fuel cell electric vehicle’s fast filling time and high efficiency.

■ Hydrogen can also serve as fuel for internal combustion engines.

■ The energy in 1 kilogram of hydrogen gas is about the same as the energy in 2.8 kilograms of gasoline.

■ Hydrogen can be transported through gas pipelines, minimising disruption and reducing the amount of expensive infrastructure needed to build a new hydrogen transmission network.

■ Hydrogen is abundant in our environment. It’s stored in water (H2O), hydrocarbons (such as methane, CH4), and other organic matter.

■ Hydrogen can be produced from a variety of domestic resources, such as natural gas, nuclear power, biomass, and renewable power like solar and wind.

■ Hydrogen is a clean fuel that, when consumed in a fuel cell, produces only water.

■ Hydrogen is a clean alternative to methane, also known as natural gas.

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.

Why is hydrogen significant as a future clean energy source?

For many years, we’ve used natural gas to heat our homes and businesses, and for power stations to generate electricity. In the UK, 85% of homes and 40% of the country’s electricity currently relies on gas; in the US, 47% of households rely on natural gas and 36% on electricity.

Methane is the main constituent of ‘natural gas’ from oil and gas fields. We’ve continued to use natural gas because it’s a readily available resource, it’s cost effective and it’s a cleaner alternative to coal – the dirtiest fossil fuel that we historically relied on for heating and to generate electricity.

When natural gas is burnt, it provides heat energy. But a waste product alongside water is carbon dioxide, which when released into the atmosphere contributes to climate change. Burning hydrogen does not release carbon dioxide.

What are the various types of hydrogen depending on the type of production used?

Hydrogen is an invisible gas. But depending on the type of production used, different colour names are assigned to the hydrogen. Green hydrogen, blue hydrogen, brown hydrogen, yellow hydrogen, turquoise hydrogen and pink hydrogen. 

Green hydrogen

Green hydrogen is made by using clean electricity from surplus renewable energy sources, such as solar or wind power, to electrolyse water. Electrolysers use an electrochemical reaction to split water into its components of hydrogen and oxygen, emitting zero-carbon dioxide in the process.

Must read: Green Hydrogen and its uses

Blue hydrogen

Blue hydrogen is produced mainly from natural gas, using a process called steam reforming, which brings together natural gas and heated water in the form of steam. The output is hydrogen, but carbon dioxide is also produced as a by-product.

It also includes the use of carbon capture and storage (CCS) to trap and store this carbon. Blue hydrogen is sometimes described as ‘low-carbon hydrogen’, as the steam reforming process doesn’t actually avoid the creation of greenhouse gases.

Grey hydrogen

Currently, this is the most common form of hydrogen production. Grey hydrogen is created from natural gas, or methane, using steam methane reformation but without capturing the greenhouse gases made in the process. Grey hydrogen is essentially the same as blue hydrogen, but without the use of carbon capture and storage.

Black and brown hydrogen

Using black coal or lignite (brown coal) in the hydrogen-making process, these black and brown hydrogen are the absolute opposite of green hydrogen in the hydrogen spectrum and the most environmentally damaging.

Pink hydrogen

Pink hydrogen is generated through electrolysis powered by nuclear energy. Nuclear-produced hydrogen can also be referred to as purple hydrogen or red hydrogen.

Turquoise hydrogen

Turquoise hydrogen is made using a process called methane pyrolysis to produce hydrogen and solid carbon.

Yellow hydrogen

Yellow hydrogen is the hydrogen made through electrolysis using solar power.

White hydrogen

White hydrogen is a naturally occurring, geological hydrogen found in underground deposits and created through fracking.