Hydrogen energy
Introduction
Hydrogen is the lightest and most abundant element in the universe. On Earth, it occurs naturally in compound form with other elements e.g hydrogen combined with oxygen forms water while hydrogen combined with carbon forms hydrocarbons that are found in fossil fuels (coal, gas, petroleum)1.
Hydrogen is produced through several methods
Since it does not exist by itself, it has to be produced from compounds that contain it, for example from water hence making it a secondary source of energy2. Hydrogen can be produced from many different sources in different ways to be used as a fuel. These different techniques result into the rainbow of hydrogen colors; grey hydrogen, blue hydrogen, black and brown hydrogen, pink hydrogen, and green hydrogen.
grey hydrogen
For the longest time, grey hydrogen has been the most common form of hydrogen. It is produced via a method called steam methane reformation (SMR), which involves heating methane from natural gas with steam, usually with a catalyst, to produce a mixture of carbon monoxide and hydrogen3. Carbon monoxide reacts with oxygen to form carbon dioxide4. While this process has proven to be highly effective, it results in the release of significant amounts of carbon dioxide5. Around 71% of the hydrogen in the world is grey hydrogen6.
blue hydrogen
Blue hydrogen is produced in the same manner as grey hydrogen, only that the process of producing blue hydrogen involves carbon capture and storage (CCS). This means that instead of carbon dioxide being released in the air, it is captured using carbon capture technology and stored or repurposed. By capturing these emissions, the overall carbon footprint of the hydrogen production process is significantly reduced7.
black and brown hydrogen
Brown hydrogen (made from brown coal) and black hydrogen (made from black coal) are produced via gasification8. Gasification is a process that converts any carbon-based raw material such as coal into fuel gas, also known as synthesis gas (syngas). The process occurs in a gasifier, generally a high temperature/pressure vessel where oxygen (or air) and steam are directly contacted with coal. The syngas is composed primarily of the colorless, odorless, highly flammable gases carbon monoxide and hydrogen. It can be further converted to hydrogen and carbon dioxide by adding steam and reacting over a catalyst in a water-gas-shift reactor9.
Before we look at the last two types of hydrogen, we need to explore a technique called electrolysis, which is a method used to generate both types. Electrolysis is the process of using electricity to split water into hydrogen and oxygen. This reaction takes place in a unit called an electrolyser.
Electrolysers can range in size from small ones used in the lab to large-scale central production facilities10. In high school chemistry under the Kenyan system, we were introduced to the concept of electrolysis through a simple experiment like the one shown below.
The goal was to demonstrate how passing an electric current through water splits it into two elements: hydrogen and oxygen. At the cathode, hydrogen ions (H⁺) gain electrons to form hydrogen gas (H₂) while at the anode, hydroxide ions (OH⁻) lose electrons to produce oxygen gas (O₂).
Large scale electrolysis makes use of large electrolysers like the one shown below, to produce hydrogen in large scale.
pink hydrogen
Pink hydrogen is generated through electrolysis of water by using electricity from a nuclear power plant11. It is considered a low-carbon or even carbon-free option because nuclear power doesn’t emit carbon dioxide during electricity generation.
green hydrogen
Green hydrogen is hydrogen produced through electrolysis of water using electricity generated entirely from renewable energy sources like solar, wind, or hydropower. This results in very low or zero carbon emissions12.
Hydrogen has a variety of applications.
Firstly, it is used in fuel cells for electricity generation and to power vehicles. Hydrogen fuel cells produce electricity by combining hydrogen and oxygen atoms. The hydrogen reacts with oxygen across an electrochemical cell , similar to a battery, to produce electricity, water, and small amounts of heat13. Fuel cells can be used in a wide range of applications, providing power for applications across multiple sectors, including transportation, industrial/commercial/residential buildings, and long-term energy storage for the grid in reversible systems14.
In the refining industry, hydrogen is used to remove impurities and increase the yield of high-quality refined products. The process of removing impurities from crude oil involves breaking down large hydrocarbons into smaller ones. This is achieved through a process called hydrogenation, where hydrogen is used to convert heavy crude oil fractions into lighter, more valuable products such as gasoline, diesel, and jet fuel15.
Hydrogen is also used in producing renewable diesel. This is diesel made from fats and oils, such as soybean oil or canola oil, and is processed to be chemically the same as petroleum diesel. Through a process known as hydrotreating, which is the main method commercial plants use to produce this type of diesel, lipids are reacted with hydrogen under elevated temperatures and pressures in the presence of a catalyst16.
Hydrogen is a key ingredient in the production of Ammonia. Ammonia is produced in the Haber-Bosch process where hydrogen is mixed with nitrogen and together processed at high temperature and pressure with a catalyst to produce ammonia. The most common uses of ammonia are in the production of fertilisers, as a refrigerant and to make plastics and other products. Ammonia produced using green hydrogen is called green ammonia17.
Renewables provide intermittent power. When the wind stops blowing and the sun goes down, there needs to be a way to store this excess energy so that it can be used on demand. In Australia, hydrogen is being explored as a way to store this energy, to be used to power industrial operations or exported to other regions18.
Certain governments are spearheading efforts to harness the potential of green hydrogen technology.
China has become the largest hydrogen producer and consumer in the world, with more than 33 million tons of annual demand. The country has a goal of reaching 100 GW green hydrogen development by 2030, with a focus on utilization in the chemicals, steel, and heavy-duty transportation sectors 19.
Saudi Arabia is also coming in closely with the NEOM Green Hydrogen Project. Once the project is completed in 2026, it will be the world’s largest utility-scale, commercially-based hydrogen facility powered entirely by renewable energy20.
In September 2024, the U.S. Internal Revenue Service (“IRS”) released proposed regulations regarding the Clean Hydrogen Production Tax Credit introduced in the Inflation Reduction Act of 2022 (“IRA”) which is designed to offset the costs of production for clean hydrogen. This credit is meant to reduce the cost of clean energy to $1 per kilogram from the current cost of $5 per kilogram, and make the production of clean hydrogen more economical. More details on this regulation can be found on this page.21
Several companies are also leading the way in driving this innovation.
SSAB, a company based in Sweden is revolutionizing how steel is made. For the longest time, coal has been used as a raw material in the steel-making process. The coal used to make steel is heated without air in an oven at temperatures of as much as 2,060°F (1,125°C), until most of its volatile matter is released. During this process, it softens, then liquefies, and re-solidifies into a hard porous material called “coke”. The coke, which is a porous carbon-rich material, is mixed with iron ore and limestone to make molten iron, which is then further treated and heated to make steel22.
SSAB is making steel differently. They have invented the world’s first fossil free steelmaking technology with largely no carbon footprint. This technology, known as HYBRIT, uses green hydrogen instead of coal in the ore reduction process, and emits water instead of carbon dioxide23. Their goal is to eliminate carbon dioxide emissions from the steelmaking process by using only fossil-free feedstock and fossil-free energy in all parts of the value chain24.
Plug Power Inc., an American company based in NewYork is engaged in the development of hydrogen fuel cell systems that replace conventional batteries in equipment and vehicles powered by electricity. These fuel cells power electric forklifts with zero emissions, meaning they only emit water and heat as byproducts. This contributes to cleaner air within facilities and significantly reduces the carbon footprint of material handling operations25. Their fuel-cells have been used to power forklifts in Amazon, Walmart and HomeDepot.
Accelera by cumins is another company involved in fuel cell and hydrogen fuel technology. The company has electrolysers in operation around the world, enabling industrial manufacturing to produce green hydrogen and decarbonize production processes for steel, oil refining, ammonia and methanol26. They are also playing a huge part in decarbonizing27 the transport sector. Their fuel cell systems are powering the world’s first fleets of hydrogen-powered trains, which are a proven alternative to diesel combustion engines 28.
ZeroAvia is a company in California, USA with facilities in Bristol UK that is actively working towards decarbonizing air transport by developing hydrogen-powered aviation technology. Their technology converts hydrogen into electricity to power aircraft engines, aiming to replace conventional fossil fuels used in aviation29.
Hydrogen, as a source of energy has its challenges.
Given that hydrogen does not exist on its own, it needs to be extracted from its compound form either through electrolysis, steam methane reformation or gasification as we saw earlier. These processes require a significant amount of energy to achieve. This energy can be more than that gained from the hydrogen itself as well as being expensive30.
Another challenge (or fear) is that too much hydrogen leakage along the supply chain may have serious unintended effects in the atmosphere and for global warming. This is because hydrogen gas easily reacts in the atmosphere with the same molecule primarily responsible for breaking down methane, a potent greenhouse gas. If hydrogen emissions exceed a certain threshold, that shared reaction will likely lead to methane accumulating in the atmosphere, with decades-long climate consequences31.
The high cost of fuel cells and the limited availability of hydrogen fueling stations have limited the number of hydrogen-fueled vehicles in use today. Production of hydrogen-fueled vehicles is limited because people won’t buy those vehicles if hydrogen refueling stations are not easily accessible, and companies won’t build refueling stations if they don’t have customers with hydrogen-fueled vehicles32.
Nevertheless, as hydrogen production technology continues to improve, the cost of hydrogen fuel is expected to decrease, making it a more accessible option for businesses. Companies involved in heavy industry, transport, or large-scale manufacturing may find hydrogen to be an ideal solution for meeting their energy needs while reducing their environmental impact33.
Footnotes
Steam Methane Reforming Carbon Capture: The Future of Clean Energy↩︎
Renewable Energy Australia: Trends and Future Opportunities↩︎
Chart: Which countries are leading the green hydrogen race?↩︎
U.S. IRS Releases Guidance for Clean Hydrogen Production Tax Credit↩︎
HYBRIT: SSAB, LKAB and Vattenfall first in the world with hydrogen-reduced sponge iron↩︎
Hydrogen Fuel Cell Forklifts: The Impact of Fuel Cells in Material Handling↩︎
How economies of scale will increase hydrogen technologies accessibility and adoption↩︎
Decarbonization aims to lower the amount of carbon dioxide emitted from human activity, with the ultimate goal of eliminating all human-made carbon dioxide emissions in their entirety.↩︎
Switching to hydrogen fuel could prolong the methane problem↩︎
Renewable Energy Australia: Trends and Future Opportunities↩︎