Is hydrogen the ideal new carbon-neutral fuel?

Hydrogen, the most common element, is one of the lightest of the chemical elements and has the simplest atomic structure: one electron orbiting around a proton. It is mainly found combined with oxygen as water or in organic matter, including plants, natural gas, oil and coal.

Are there different types of hydrogen?

Hydrogen is considered pivotal in developing sustainable energy systems, the key to these solutions depends on how the hydrogen is produced. The most conventional method for producing hydrogen is steam reforming, where steam reacts with natural gas. The result is commonly known as “grey” hydrogen, which accounts for roughly 95 percent of all the hydrogen produced today. Steam reforming releases a slightly smaller amount of greenhouse gas emissions into the atmosphere than burning lignite or bituminous coal to produce “brown” or “black” hydrogen. But taken together, they are responsible for 830 million metric tons of CO₂ per year.

“Blue” hydrogen uses the same reforming processes as “black,” “brown” or “grey” hydrogen, but employs carbon capture and storage equipment to store CO₂ emissions underground. Some advocates believe “blue” hydrogen could be a short-term solution to driving the hydrogen market. Critics, however, stress that the process is inefficient, energy intensive, costly and not green enough.

The production of “green” hydrogen through the electrolysis of water with electrical energy from renewable resources is entirely free of greenhouse gas emissions. This reaction takes place inside a unit called an electrolyzer, where water is split into hydrogen and oxygen. Electrolysis is the gold standard for sustainable hydrogen production and industrial-scaled production plants can be expected as demand increases.

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Why is hydrogen important to the energy transition?

Hydrogen, the simplest and most abundant element in the universe, also holds the greatest potential for decarbonizing our economy. Hydrogen contains no greenhouse gases, and when generated by electrolysis via renewable energy, it becomes a carbon-free carrier of energy commonly referred to as green hydrogen. When comparing similar volumes, hydrogen contains nearly three times more energy than oil and natural gas and leaves only water behind when burned.

Green hydrogen is a key element in the energy transition with the potential to decarbonize a vast variety of sectors. It can either be used directly as an energy source for industrial applications or further converted into other climate-neutral fuels – or efuels – using Power-to-X technology. Efuels such as synthetic natural gas (SNG), green ammonia and green methanol, among others, can be used as drop-in fuels to power today’s combustion engines without putting a strain on the climate, making them attractive alternatives for transport and power generation. According to the International Energy Agency, “power generation and transport accounted for over two-thirds of global greenhouse gas emissions in 2019” due to the use of fossil fuels.

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What are the challenges to overcome?

The current challenges to a green hydrogen market are a lack of infrastructure and cost – two issues that often go hand in hand with the implementation of new technology. In this case, however, both the demand and urgency to move toward a net-zero economy are driving the change to overcome these issues. Already governments around the world are defining targets and creating budgets to build a hydrogen infrastructure, and as with renewable energy, decreasing costs for hydrogen technology and subsidies will make green hydrogen and efuels a realistic and viable solution for a sustainable world.