With climate change driving the development of new energy solutions, green hydrogen is receiving more attention as a possible solution to decarbonizing energy sources. Although the technology is still developing, green hydrogen holds excellent promise as a truly clean energy source.
This article will explain green hydrogen and its benefits, challenges, and potential to change the energy industry radically.
What Is Green Hydrogen?
If you’ve forgotten your chemistry, hydrogen is the lightest and most common chemical element. It’s colorless, odorless, and non-toxic, and it’s most commonly found in pairs (known as a diatomic molecule) and notated as H2. Hydrogen accounts for most of the earth’s matter, though not by weight. It’s also an essential component of water — H2O.
Green hydrogen refers to how hydrogen is generated from water; its production is climate-neutral because it uses renewable power sources. When burned, hydrogen reacts with oxygen to produce water and release energy – no carbon emissions! Soon, green hydrogen will be a zero-emission energy source.
When we talk about green hydrogen, we mean splitting water into its constituent elements, hydrogen and oxygen, using renewable electricity. However, there are other ways to produce hydrogen, which are also designated by color.
Is Hydrogen Green Energy?
One of the most common forms of hydrogen currently being produced is grey hydrogen, which uses steam to split methane (CH4) into carbon dioxide (CO2) and a diatomic hydrogen molecule (H2), a method called steam methane reforming. However, since carbon dioxide is a greenhouse gas, energy generated using grey hydrogen can’t be considered clean energy.
Similarly with blue hydrogen, produced in the same manner as grey hydrogen, carbon dioxide emissions are partially addressed through carbon capture and storage. However, since carbon capture can’t adequately retain all the carbon dioxide emissions, it’s also not considered a zero-emission technology.
On the other hand, green hydrogen is a clean energy technology. The electrolysis process uses water to produce hydrogen, making it green energy.
How Is Green Hydrogen Produced?
Using a carbon-free electricity source, the electrolysis of water breaks up water molecules to produce oxygen and hydrogen (H2). When burned, hydrogen burns cleanly, with a water vapor residue.
Electrolysis of water uses electrolyzers ranging from home appliance-size to large-scale production facilities. In addition, there are several types of electrolyzers, depending on the type of electrolyte material involved.
- In polymer electrolyte membrane (PEM) electrolyzers, water reacts with the anode to form hydrogen ions that travel across the PEM to the cathode and become hydrogen gas. PEM electrolyzers operate at temperatures between 70 and 90 degrees Celsius.
- With alkaline electrolyzers, hydroxide ions move through the electrolyte (usually sodium or potassium hydroxide) from the cathode side to the anode side. Hydrogen is generated on the cathode side.
- Solid oxide electrolyzers operate at high temperatures (700-800 degrees Celsius). Steam at the cathode forms hydrogen gas and oxygen ions, which pass through a solid ceramic membrane.
How Can Green Hydrogen Be Used?
While still a developing technology, green hydrogen shows excellent promise over other hydrogen technologies, such as grey or blue hydrogen processes. As green hydrogen technology becomes more widely accessible, it will impact many industry sectors.
Green Hydrogen in Transportation
Although hydrogen fuel cell electric vehicles (FCEVs) currently account for 0.5% of new low-emissions vehicles sold, the expansion of hydrogen fuel cell vehicles is underway. For example, Hyundai has announced plans to manufacture 500,000 FCEVs by 2030. In addition, Paris, France, is already working on converting its taxi fleet to hydrogen-powered electric vehicles.
Meanwhile, several cities in the European Union already use FCEV technology to power their waste-collection fleets. The HECTOR Project has launched seven such vehicles in Germany, the Netherlands, Belgium, Scotland, and France. In addition, the project is testing the cars for normal road operations.
Although conversion to hydrogen fuel cells is just beginning, the International Energy Agency forecasts significant growth over this small start, based on sales in the first half of 2021.
Green Hydrogen and Industry
Heavy industry already uses grey or blue hydrogen in applications such as steel production. Green hydrogen is beginning to be used in Europe, where the steel production sector faces serious opposition due to its polluting effect on the environment.
Green hydrogen can replace coal in the iron-ore purification process. Instead of carbon dioxide as a byproduct, green hydrogen produces water vapor, eliminating the greenhouse gas from the equation.
Other industry sectors, such as the petrochemical and chemical sectors, can also use green hydrogen in their production process instead of more conventional forms of hydrogen.
Green Hydrogen and Oil Refineries
Oil refineries used approximately 40 million tons of hydrogen in 2020. However, the hydrogen is produced mainly by steam methane reforming, a process that still emits greenhouse gases in the form of carbon monoxide and carbon dioxide.
Shell’s Rhineland refinery in Germany currently uses electrolyzers. An additional refinery in the Netherlands is under construction. Europe, in general, is leading the way; refineries there are developing a 1.3 gigawatt capacity with an additional 700 MW slated for development at merchant hydrogen producers (hydrogen makers and retailers) near refineries. The aim is to replace grey hydrogen produced through steam methane reforming.
Green Hydrogen in Homes
In the United Kingdom (U.K.), the government is aiming to adopt hydrogen-ready boilers for 3 million homes by 2030. Boilers currently use natural gas for home heating and hot water in the U.K. However, two show homes — entirely powered by hydrogen — in Gateshead, England, have launched the Tory government’s Hydrogen Strategy.
The more likely scenario is that a mix of hydrogen and natural gas will mark the energy transition to green hydrogen use. The advantage of mixed-use is that, for the most part, hydrogen and natural gas can use existing pipelines for delivery. As a result, most gas appliances can successfully run on a blend of 20% hydrogen and 80% natural gas with a relatively simple valve refitting.
Is Green Hydrogen Safe?
Public perception is that hydrogen is extremely dangerous, and that’s true to some degree. It is highly flammable, yet fossil fuels such as natural gas and gasoline are far more volatile. In addition, hydrogen requires 18-59% oxygen concentration to explode; gasoline only requires an oxygen concentration between 1% and 3%.
Unlike fossil fuels, hydrogen is non-toxic and, compared to fossil fuel combustion engines, emits no greenhouse gases — only water vapor and a bit of warm air. As a result, a hydrogen leak doesn’t contaminate the environment or threaten health.
Finally, hydrogen has been used in oil refineries and fertilizer production for years. As a result, robust safety procedures, controls, and guidelines are in place. These risk-mitigation protocols focus on responsibly producing and using hydrogen, making it less dangerous than one might suppose.
Is Green Hydrogen Profitable?
Although used in industry and promoted by governments worldwide, green hydrogen is not as widely used as necessary to meet climate initiatives because of the high price of its production, approximately $4-$5 per kilogram. However, most of the cost is the electricity required for hydrogen production.
To meet the U.S. government’s price goal of $1/kg by 2030, it’ll require greater use of renewable power. Although renewable sources such as solar energy and wind turbines can power hydrogen electrolysis now, the production scale is limited by the extent of renewable sources‘ deployment and utilization.
What Is a Hydrogen Economy?
Currently, most nations depend on an oil economy, in which oil is the primary fuel responsible for delivering energy and services. An economy that relies on hydrogen in that role is a hydrogen economy. A green hydrogen economy presupposes that hydrogen is produced economically and in an environmentally friendly manner.
One way to achieve that goal is to further the development of fuel cells and fuel cell electric vehicles (FCEVs). When one considers hydrogen as an energy system and a method of energy storage, hydrogen fuel cells can be one alternative in resolving the problem of energy storage.
Because hydrogen is also explosive, it has potential as an alternative fuel for conventional internal combustion engines (ICEs). Replacing gasoline and diesel with hydrogen would eliminate greenhouse gas emissions.
Most developed nations, including Japan, the U.S., Australia, Chile, Finland, England, and the countries of the European Union, are moving toward a hydrogen economy through the development of electrolyzers to produce green hydrogen. In February 2021, the IEA’s Hydrogen Project database had recorded 320 hydrogen production demonstration projects globally. The interest has been driven by the 2015 Paris Agreement goals to reduce greenhouse gas emissions sharply by 2050.
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What Are the Advantages of Green Hydrogen?
Green hydrogen, produced with renewable energy sources, is environmentally friendly. As an energy source, it adapts well to energy storage and is easy to transport. Some green hydrogen benefits include:
- Converts to heat or electricity. It has the flexibility for use domestically in supplying energy and electricity.
- Can be used as a raw material in the steel industry. Electrolysis technologies are approaching profitability, which will catapult green hydrogen production. Fuel cells are successfully used already as an energy storage solution.
- Eliminates carbon dioxide emissions. Hydrogen electrolysis uses water to produce hydrogen ions with oxygen and water vapor as byproducts.
Could Hydrogen Replace Natural Gas?
Researchers and green-energy producers currently see green hydrogen as a solution for powering FCEVs and as a means of utility-scale renewable energy storage. Another use includes stationary fuel cell systems used in buildings to power heating and electricity.
Proposals already exist for blending hydrogen into existing natural gas pipelines; in some cases, they’re already doing so at low concentrations through demonstration projects. Such projects investigate hydrogen end-use in household appliances and transport through existing pipeline networks. If successful, these projects could significantly impact natural gas use.
What Companies Make Green Hydrogen?
According to the Business Research Company, as reported by Globe Newswire in November 2021, several large companies are involved in green hydrogen production. They include the following:
- Air Liquide
- Air Products and Chemicals Inc.
- Ballard Power Systems
- Engie
- Fuel Cells Works
- Green Hydrogen Systems
- Hydrogenics
- Linde Plc
- Nel Hydrogen
- Nikola Motors
- Plug Power Inc.
- Siemens Energy Global GmbH & Co. KG
- Solena Group
- Toshiba Energy Systems & Solutions Corporation
- Enapter
- ERGOSUP
- Loop Energy Inc.
- Tianjin Mainland Hydrogen Equipment Co. Ltd.
The report forecasted the global green hydrogen market from just over half a billion dollars in 2020 to nearly three-quarters of a billion dollars in 2021. Forecasters also predict a $2.94 billion market by 2025.
Where Is the Largest Green Hydrogen Plant?
Currently, the Air Liquide 20-megawatt Bécancour facility in Quebec, Canada, is the largest hydrogen plant in the world. Powered by local hydroelectricity, the plant uses a PEM electrolyzer supplied by U.S.-based Cummins to produce green hydrogen. Plans are underway to build a larger plant in Egypt.
Is Green Hydrogen the Fuel of the Future?
Most of the hydrogen produced today is grey or blue, using steam methane reforming technology. However, the push for decarbonization of the energy-intensive production methods has resulted in increased investment in and development of green hydrogen technologies that use renewable power.
Green hydrogen proponents tout the use of wind turbines and solar power as the future wave for the production of green hydrogen. With an eye on sustainability and decarbonization of our energy systems, renewable power is poised to address the problems most developed countries face in transitioning to green hydrogen.
As governments work to reach the goals of the 2015 Paris Accord, the heavy industry faces increased pressure to reduce emissions dramatically. Green hydrogen appears to address the logistical challenges of greenhouse gas emission reductions set. There are still obstacles to overcome in the cost-effective production and distribution of green hydrogen, but the work continues toward profitability and sustainable production.
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