Green Hydrogen: The Swiss Army Knife of Energy Transition
Written by Ahad Esmaeilian and Kaveh Aflaki
Hydrogen production has a long history, dating back to the 1800s when scientists discovered that water could be converted into hydrogen and oxygen through the process of electrolysis. By the 20th century, hydrogen began to be utilized as a fuel source on a large scale, primarily derived from non-renewable fossil fuels through steam methane reforming (SMR), autothermal reforming (ATR), partial oxidation (POX), coal gasification, or oil refining. The hydrogen produced from any of the mentioned methods is known as “gray hydrogen” which results in significant greenhouse gas emissions. In contrast, green hydrogen is produced from renewable energy sources such as solar, wind, or hydroelectric power through electrolysis. Green hydrogen has gained significant attention and investment in recent years due to its potential to be used as a low-carbon fuel for transportation, industry, and power generation.
The current market offers several electrolysis technologies, each with its own advantages and disadvantages. The three major technologies are:
Alkaline Electrolysis: This is one of the oldest and most established technologies, which uses an alkaline solution such as potassium hydroxide (KOH) as the electrolyte. Alkaline electrolysis has a relatively high efficiency (70-80%) and operates at low temperatures (25-80°C), making it well-suited for large-scale hydrogen production. However, the use of an alkaline electrolyte, such as KOH, can lead to corrosion and higher maintenance costs over time. Additionally, efficiency decreases above 80°C.
Proton Exchange Membrane (PEM) Electrolysis: This technology uses a proton-conducting polymer membrane as the electrolyte and selectively allows protons to pass through, resulting in high electrical efficiency (60-70%). PEM electrolysis is compact and lightweight, making it ideal for small-scale and portable hydrogen production systems. However, it is sensitive to water impurities and requires the use of a precious metal catalyst, such as platinum, which increases costs.
Solid Oxide Electrolyzer (SOE): This technology uses a solid oxide material as the electrolyte, typically composed of ceramics like zirconia or yttria-stabilized zirconia. SOEs have a high electrical efficiency (60-80%) and can operate at high temperatures (700-1000°C), which allows for the utilization of waste heat as a source of energy. Although SOEs are a relatively new technology, further research is needed to optimize their performance, decrease costs, and improve reliability.
Power Generation, Heating & Cooling: Green hydrogen has the potential to transform various industries, including transportation, heating and cooling, industrial processes, and power generation. With its versatility and scalability, green hydrogen could significantly reduce carbon emissions and contribute to a low-carbon future. The widespread adoption of green hydrogen across industries has the potential to drive economic growth, create new jobs, and enhance energy security. It is therefore considered a critical component in the transition towards a sustainable energy system and a crucial element in the global energy mix.
The utilization of green hydrogen by utilities in the power generation and heating and cooling industries is a promising approach to reducing carbon emissions. Through hydrogen blending, where a portion of hydrogen is blended with the existing natural gas pipeline, the carbon intensity of energy delivery can be decreased. As the hydrogen proportion in the blend increases, the carbon emissions of the natural gas pipeline correspondingly decrease. This process offers a viable pathway for utilities to transition to low-carbon energy sources without requiring extensive infrastructure alterations.
Furthermore, green hydrogen can serve as an independent energy source for heating and cooling through direct use or electricity production via fuel cells. This has the potential to significantly lower the carbon footprint of the heating and cooling sector and contribute to a sustainable energy system. Additionally, in the power and utilities sector, green hydrogen can store excess renewable energy, be utilized to meet energy demand during low renewable energy generation periods, and balance the electricity grid by integrating more renewable energy.
However, the implementation of hydrogen blending into natural gas pipelines and power generation turbines poses several challenges. These include technical compatibility, where the existing natural gas infrastructure must be suitable for hydrogen; safety considerations due to hydrogen's flammable nature; cost factors such as the expenses associated with hydrogen production and transportation; and the retrofitting of existing natural gas infrastructure. Additionally, there is a need for the development of a hydrogen production and distribution infrastructure, including investments in renewable energy sources, hydrogen storage, and transportation technologies. The creation of appropriate regulations and policies to support hydrogen blending is also vital for its safe and efficient deployment, including the establishment of standards for hydrogen blending, safety protocols, and licensing for hydrogen production and distribution activities.
Green H2 has the potential to decarbonize transportation that relies on fossil fuels. H2 fuel cell vehicles, powered by green hydrogen, can convert hydrogen into electricity to drive the vehicle's electric motor. A European Commission study projects that H2 fuel cell cars could make up 14% of new European sales by 2050. OEMs such as Toyota, Honda, Hyundai, and GM produce and sell fuel cell vehicles using mature tech such as PEM fuel cells and high-pressure hydrogen storage. These advancements allow for fuel cell cars with high range and low emissions. Captive fleets like buses, delivery vans, and airport ground support can also use green hydrogen. OEMs like Toyota, Daimler, Volvo, and Nikola Motors are investing in hydrogen fuel cell trucks. A Hydrogen Council study predicts these trucks could account for 14% of the $230B global truck market by 2030 and reduce CO2 emissions by 6 gigatons per year by 2050 . Green hydrogen can also be used as marine fuel, reducing CO2 emissions for shipping. H2 fuel cell ships could reduce CO2 emissions by up to 90% compared to conventional ships, according to the International Transport Forum. Green hydrogen also has potential in aviation, to power planes and produce synthetic jet fuels. OEMs and startups are designing and piloting vessels and planes that could run on green hydrogen/ammonia. ICAO predicts hydrogen could cut aviation's CO2 emissions by 80% .
The use of green hydrogen in the transportation sector faces several challenges, including infrastructure, cost, fuel cell technology, regulatory and policy support, and public awareness and perception. To address the infrastructure challenge, hydrogen production and fueling stations need to be developed, along with hydrogen storage and transportation technologies. To reduce the cost, cost-effective green hydrogen production and fueling technologies and economies of scale in production and distribution must be established. The use of green hydrogen requires the development of advanced fuel cell technology that is cost-effective, durable, and reliable. Proper regulations and policies are necessary to support the safe and efficient deployment of green hydrogen. Finally, raising public awareness about the benefits of green hydrogen and overcoming any misconceptions is crucial to its widespread adoption.
Green hydrogen can serve as a feedstock in a variety of industries, including fertilizer, chemicals, fuels, steel, cement, glass, and microchips. This versatile and scalable energy source offers a promising solution for reducing the carbon footprint of these industries and promoting a more sustainable future. The Hydrogen Council projects that hydrogen has the potential to cut CO2 emissions in the industrial sector by up to 6 Gt by 2050.
In the fertilizer industry, hydrogen is utilized as a feedstock for the production of ammonia, a key component in many fertilizers. Currently, the ammonia production process often uses natural gas as the source of hydrogen, but green hydrogen has the potential to reduce the carbon footprint of this industry. By 2030, the market size for green hydrogen in the fertilizer industry is expected to reach $3.8 billion .
The chemical industry is a significant energy consumer and greenhouse gas emitter, with hydrogen being used in the production of chemicals like ammonia and methanol. Green hydrogen can replace the use of fossil fuels in this industry, resulting in significant reductions in carbon emissions. The market size for green hydrogen in the chemicals industry is estimated to reach $17.5 billion by 2050.
Hydrogen can also play a role in the oil and gas industry and refineries, where it can improve efficiency, reduce emissions, and upgrade heavy crude oil. Hydrogen can be used in processes like hydrotreating, hydrocracking, and hydrogenation and as a fuel to power operations in the industry. The market size for green hydrogen in the oil and gas industry and refineries by 2030 is expected to reach $18.2 billion.
In the steel industry, green hydrogen can replace fossil fuels as a reducing agent in the production of iron, reducing the carbon footprint of this industry. The market size for green hydrogen in the steel industry is estimated to reach $7.3 billion by 2050. The cement industry is also a significant contributor to global carbon emissions, and green hydrogen can be used to heat the kilns in cement production, making the industry more environmentally friendly. The market size for green hydrogen in the cement industry is estimated to reach $5.2 billion by 2030.
The production of glass requires high temperatures and energy, making it a significant source of carbon emissions. Green hydrogen can be used as an energy source in the glass melting process, reducing the carbon footprint of the glass industry. The market size for green hydrogen in the glass industry is estimated to reach $1.9 billion by 2050.
In the microchip industry, hydrogen is used as a reducing agent in the production of silicon wafers. Green hydrogen can replace traditional hydrogen made from fossil fuels, reducing the carbon footprint of this industry. The market size for green hydrogen in the microchip industry is estimated to reach $3.6 billion by 2030.
Although these industries face specific challenges in the adoption of green hydrogen, general challenges such as the high cost of production, difficulty in storage and transportation, shortage of technical expertise, and an uncertain policy and regulatory environment are also relevant. Addressing these challenges will be crucial to expanding the use of green hydrogen as a feedstock in a wider range of industries.
What is Next?
Green hydrogen is seen as a promising technology for the shift to a low-carbon energy system. Its ability to reduce carbon emissions in various industries and store/transport renewable energy makes it a crucial component in the energy transition. The global green hydrogen market is estimated to reach $80 billion by 2030 and over $2.5 trillion by 2050 . Although green hydrogen has vast potential, its widespread production and use are still in the early stages. Currently, producing green hydrogen costs $3 to $6 per kilogram, which is more expensive compared to hydrogen produced from natural gas ($1 to $2 per kilogram). However, as technology advances and economies of scale are achieved, the cost is projected to decrease to $1 to $2 by 2030, making it comparable to hydrogen from natural gas. Government subsidies and incentives worldwide will further help reduce costs and drive technological progress.
This article was edited by Ali Nabavi.