Is Green Hydrogen Considered Renewable Energy?
Introducing Green Hydrogen
Green hydrogen is hydrogen produced through electrolysis powered by renewable energy sources like solar or wind. Electrolysis uses electricity to split water into hydrogen and oxygen. When the electricity used in the process comes from renewable sources, the resulting hydrogen gas is considered “green” or renewable since no fossil fuels are used and no greenhouse gas emissions are produced.[1]
Unlike fossil fuel-based hydrogen production which emits carbon dioxide, green hydrogen emits no greenhouse gases and has significant potential as a clean energy source. Green hydrogen can be used for electricity generation, transportation, heating, or industrial processes while helping countries achieve net zero emissions goals.[2] With the right policies and investments, some experts predict green hydrogen could supply up to 25% of the world’s energy needs by 2050.[3]
Overall, green hydrogen offers a versatile way to store and transport energy from intermittent renewable sources like wind and solar. Converting renewable electricity into hydrogen fuel provides environmental benefits and can accelerate the global energy transition.
[1] https://www.weforum.org/agenda/2021/12/what-is-green-hydrogen-expert-explains-benefits/
[2] https://en.wikipedia.org/wiki/Green_hydrogen
[3] https://www.iberdrola.com/sustainability/green-hydrogen
Green Hydrogen Production Methods
Green hydrogen is produced through the electrolysis of water, which uses electricity to split water into hydrogen and oxygen. This process is considered renewable if the electricity used is generated from renewable energy sources like solar, wind, hydropower or geothermal. The most common methods for green hydrogen production are:
Water electrolysis involves passing an electric current through water to separate the hydrogen and oxygen molecules. This can be done using a device called an electrolyzer. The most common types of electrolyzers used are:
Proton exchange membrane (PEM) electrolyzers – These use a polymer electrolyte membrane and noble metal catalysts to electrolyze water. PEM electrolyzers are suited for small-scale decentralized hydrogen production.https://www.meco.com/how-is-green-hydrogen-produced/
Alkaline electrolyzers – One of the most mature electrolysis technologies, alkaline electrolyzers use a liquid alkaline electrolyte like potassium or sodium hydroxide. They have lower capital costs but can be less energy efficient.
Solid oxide electrolyzer cells (SOECs) – SOECs use a solid ceramic electrolyte and operate at high temperatures of 700-850°C. They can be more energy efficient but have high costs currently.
The choice of electrolyzer depends on factors like scale, efficiency, costs and hydrogen purity needed. But using renewable electricity, all these methods allow for clean green hydrogen production with zero carbon emissions.
Renewable Energy Sources for Green Hydrogen
Green hydrogen is produced through electrolysis using electricity generated from renewable energy sources like solar, wind, hydropower, and geothermal. These sources are considered renewable and sustainable since they do not emit greenhouse gases. Solar and wind energy are currently the most common sources for producing green hydrogen.
Solar power can provide a clean and consistent electricity supply for electrolysis to produce green hydrogen. Large scale solar farms that generate excess electricity during the day can power electrolysis. Solar energy has the potential for continued cost reductions, making it a promising renewable source for green hydrogen production. [1]
Wind energy is also frequently used for green hydrogen production. Excess wind capacity that would otherwise be curtailed can be utilized to power electrolysis. Like solar, wind power has been rapidly scaling and costs have declined. Wind is already an economical electricity source in many regions, providing low-cost power for green hydrogen production. [2]
Other renewable sources like hydropower and geothermal can contribute electricity for electrolysis as well. However, they currently play a smaller role compared to solar and wind. Still, all emissions-free electricity sources will help scale up green hydrogen production.
Benefits of Green Hydrogen
Green hydrogen has several benefits that make it a promising clean energy source. One of the main benefits is its emissions reduction potential. When green hydrogen is produced from renewable energy and water using electrolysis, no greenhouse gases are emitted in the production process. Green hydrogen can then be used for electricity generation, transportation, heating, and industrial processes without releasing any carbon emissions. This gives it great potential to help decarbonize multiple sectors of the economy.
Another key benefit of green hydrogen is its ability to store energy. Renewable sources like solar and wind produce intermittent power based on weather conditions. Green hydrogen provides a way to capture excess renewable electricity and convert it into hydrogen through electrolysis. This hydrogen can then be stored and used later when renewable generation is lower. Green hydrogen can function as a large-scale energy storage medium and provide greater flexibility to energy systems with high shares of renewables.
Green hydrogen is also poised to become an important zero-emissions transportation fuel. Fuel cell vehicles powered by green hydrogen emit only water vapor from their tailpipes. Green hydrogen can be used for fuels like ammonia and methanol that are suitable for marine vessels, planes, trucks, and other heavy transport that is difficult to electrify. As a transportation fuel, green hydrogen has the potential to significantly reduce emissions from the transport sector.
Challenges With Green Hydrogen
One of the main challenges with green hydrogen currently is the high costs associated with production, storage, and transportation. As noted in a report by 100%RE, green hydrogen production results in costs of $3 to $8 per kg, which is not yet competitive with fossil fuel alternatives (https://100re-map.net/en/green-hydrogen-market-potentials-and-challenges/). Significant investments into research and infrastructure will be needed to bring down these costs.
The lack of infrastructure for distributing hydrogen is another barrier. Hydrogen is difficult to transport over long distances through pipelines due to its low density. Compressing or liquefying hydrogen for transportation requires high amounts of energy and specialized equipment (https://smartgrid.ieee.org/bulletins/february-2021/green-hydrogen-challenges-for-commercialization). Major infrastructure developments will be required to enable a large-scale hydrogen economy.
There are also technical difficulties with producing green hydrogen at scale. The electrolysis process faces challenges such as low reaction rates and intermittent renewable electricity supplies. Storing large volumes of hydrogen sustainably is also an unsolved issue currently (https://www.fastcompany.com/90889357/the-problem-with-green-hydrogen). More research and innovation is still needed to make green hydrogen viable as a widespread energy source.
Green Hydrogen Storage and Transportation
Green hydrogen needs to be stored and transported from where it is produced to where it will be used. The most common methods for storing hydrogen are as a compressed gas or a cryogenic liquid. Compressed hydrogen gas is stored in high-pressure tanks at pressures up to 10,000 psi. This allows more hydrogen to be stored in a smaller space compared to ambient pressure storage. However, compression causes energy losses. Liquid hydrogen is stored at extremely cold temperatures below -423°F, which condenses the hydrogen into a liquid state at a much higher density than compressed gas. However, liquefaction requires a tremendous amount of energy (https://www.energy.gov/eere/fuelcells/hydrogen-delivery).
For transportation, hydrogen gas can be moved through pipelines, similar to natural gas systems. Pipelines are the most economical way to transport large quantities of hydrogen over long distances. However, building new hydrogen pipelines requires major infrastructure investments. Trucking is used to transport compressed gas cylinders or liquid hydrogen for shorter distances. Liquid hydrogen trucks are double-walled vacuum-insulated cryogenic tankers. While trucking has greater flexibility, it leads to higher costs and energy losses compared to pipelines (https://www.sciencedirect.com/science/article/pii/S1364032122009947).
Green Hydrogen Usage
Green hydrogen has many potential uses across industries and applications. One major usage is as a zero-emission fuel for fuel cell electric vehicles (FCEVs). Fuel cells combine hydrogen and oxygen to generate electricity that powers the vehicle’s motor. Compared to conventional internal combustion engines, FCEVsoffer longer driving ranges and faster refueling times than battery-powered electric vehicles, with water as the only byproduct. Major car manufacturers like Toyota, Hyundai, and Honda already have FCEV models on the market.
Green hydrogen can also be used for power generation. Fuel cells can convert hydrogen into electricity without direct greenhouse gas emissions. The hydrogen is combined with oxygen from the air in the fuel cell to produce electricity, heat, and water. This makes hydrogen a clean energy carrier and alternative to fossil fuels for powering data centers, vehicles, and remote locations off the grid. Fuel cell systems powered by green hydrogen deliver reliable and resilient zero-carbon electricity.
Additionally, green hydrogen enables the decarbonization of industrial processes that currently rely on fossil fuels. Industries like steel, chemicals, refining, and cement production can leverage green hydrogen for high-temperature heating, chemical feedstock, and reducing iron ore. Green hydrogen provides a pathway for these carbon-intensive sectors to reduce emissions and meet decarbonization goals.
Global Green Hydrogen Projects
There are several major green hydrogen projects being developed around the world to scale up the production and use of renewable hydrogen.
One of the largest is the NEOM Green Hydrogen Project in Saudi Arabia, which aims to produce 650 tons of hydrogen per day powered by 4 GW of wind and solar energy. It is expected to be operational by 2026 and will provide hydrogen for export as well as domestic transportation and industrial uses.
The Western Green Energy Hub in Australia plans to build wind and solar farms capable of powering up to 3,500 MW of electrolyzers to produce green hydrogen. The $36 billion project could start exports by 2028 and reach full scale of 28 GW by 2040.
In Spain, the Reckaz consortium is developing a project to install 30 GW of renewables and produce over 1 million tons of green hydrogen per year by 2030. The hydrogen will be used for industrial applications, injected into the gas grid, and exported to other European markets.
Other major projects are being planned in Chile, China, Canada, the Middle East and across Europe. As more very large-scale green hydrogen facilities come online in the coming years, it could help drive down costs and increase adoption in hard-to-decarbonize sectors.
Green Hydrogen Policies and Investments
Many governments around the world are establishing policies and incentives to accelerate the adoption of green hydrogen. These policies aim to make green hydrogen cost-competitive with fossil fuels by helping scale up production and reduce costs through research, development, and deployment support.
The European Union unveiled its Hydrogen Strategy in 2020, which includes targets to install 40 GW of renewable hydrogen electrolyzers and produce 10 million metric tons of renewable hydrogen by 2030. The EU is also funding large-scale hydrogen projects through initiatives like the European Clean Hydrogen Alliance.
The United States passed the Inflation Reduction Act in 2022, which includes tax credits for clean hydrogen production that start at $0.60 per kg and rise to $3 per kg by 2032. Multiple U.S. states like California, New York, and Texas also have additional incentives and policies to promote green hydrogen.
Leading countries in Asia like Japan, South Korea, and Australia have all released national hydrogen roadmaps and are investing billions of dollars into green hydrogen research, pilot projects, and infrastructure over the next decade.
Major energy and industrial corporations are also making large investments into green hydrogen production and usage. Companies like Plug Power, Air Products, Linde, Siemens Energy, and others have announced plans to build green hydrogen production facilities worldwide.
The Future of Green Hydrogen
The outlook for green hydrogen is promising, with demand projected to grow substantially in the coming years and decades.
According to a report by PwC, green hydrogen demand is expected to see steady growth until 2030, driven by current projects under construction and increased policy support and investments [1]. Major energy companies like Plug Power are investing billions into large-scale green hydrogen production to supply growing industries such as transportation and electricity generation [2].
With most green hydrogen today produced via electrolysis powered by renewable electricity, this growth will require major investments in additional solar, wind, hydro and other renewable energy sources. Government policies, especially in Europe and Asia, are aiming to accelerate green hydrogen development through funding, infrastructure development, and public-private partnerships.
In summary, while still in its early stages, green hydrogen is poised to play an increasing role in the global energy system as a versatile, renewable fuel and energy storage medium. Its renewable status will depend on powering its production from carbon-free energy sources like solar and wind. With the right policies and investments, green hydrogen can provide a path to decarbonize hard-to-abate sectors and support the transition to net-zero economies.
