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Green Hydrogen: Unlocking Decarbonization Potential in Hard-to-Abate Sectors

1. Introduction

Green hydrogen, an essential aspect of sustainable energy solutions, has been gaining significant attention in the global fight against climate change. This introduction section provides an overview of green hydrogen and its relevance in the ongoing energy transition.

1.1 Overview of Green Hydrogen

Green hydrogen is a type of hydrogen fuel that is produced through the process of electrolysis, where electricity is used to split water into hydrogen and oxygen. This process becomes “green” when the electricity used is sourced from renewable energy such as wind, solar, or hydropower. As such, green hydrogen production results in zero carbon emissions, distinguishing it from “gray” or “blue” hydrogen, which are produced from fossil fuels and involve carbon capture and storage respectively.

As the most abundant element in the universe, hydrogen has immense potential as an energy carrier. However, its widespread use has been limited by the challenges associated with production, storage, and transportation. Green hydrogen, however, with its environmentally friendly production process, could overcome these challenges and transform the global energy landscape.

1.2 The Relevance of Green Hydrogen in Energy Transition

The world is currently in the midst of an energy transition, moving away from fossil fuels towards cleaner, renewable sources of energy. This shift is essential to mitigate the impacts of climate change and achieve the targets set by international agreements such as the Paris Agreement.

In this transition, green hydrogen plays a crucial role. It serves as a clean, sustainable, and versatile energy carrier that can be used across a variety of sectors, including transportation, industrial processes, heating, and power generation. It’s particularly relevant for sectors that are hard to abate, meaning those sectors where it is difficult to reduce emissions, such as steelmaking, aviation, shipping, and heavy-duty transport.

Moreover, green hydrogen can serve as a means of storing and transporting energy, particularly from intermittent renewable sources like wind and solar. It can be used to balance the grid, store excess energy for use when demand is high or supply is low, and can even be transported over long distances, making it a key enabler of a global renewable energy system.

2. Hard-to-Abate Sectors: An Overview

As we strive to reduce carbon emissions to mitigate the impacts of climate change, there are certain sectors of the economy that pose significant challenges. These are referred to as hard-to-abate sectors. This section provides an overview of these sectors, defining their characteristics and outlining the key sectors and their specific challenges.

2.1 Definition and Characteristics

Hard-to-abate sectors are those parts of the economy where it is particularly difficult to eliminate greenhouse gas emissions due to technical or economic reasons. The challenges stem from the nature of their operations, their reliance on specific processes or raw materials, and the absence of economically viable or technically feasible alternatives. For these sectors, the path to decarbonization is more complex than just switching to renewable energy sources.

Characteristics of hard-to-abate sectors include:

  1. High-intensity energy usage: These sectors often involve processes that require large amounts of energy, which currently rely heavily on fossil fuels.

  2. Process emissions: Some sectors produce emissions not only from energy use but also from the industrial processes themselves.

  3. Lack of viable alternatives: In many cases, there are few or no commercially viable low-carbon alternatives available.

2.2 Key Sectors and Their Challenges

Several key sectors are generally recognized as hard-to-abate, including:

  1. Heavy Industry: This includes sectors like steel, cement, and chemicals manufacturing. These industries have high energy requirements and often produce emissions as part of their core processes. For instance, in steelmaking, carbon is used not only as an energy source but also to reduce iron ore to iron.

  2. Transport: Certain segments of the transportation sector, like aviation, shipping, and long-haul road transport, are hard to electrify due to energy density requirements, operational constraints, or long lifecycle and slow turnover of capital assets.

  3. Building and Construction: While some progress has been made in making buildings more energy-efficient, the sector still relies on carbon-intensive materials and processes. The construction sector also faces the challenge of retrofitting existing buildings.

  4. Agriculture: While not an industry in the traditional sense, agriculture is a significant contributor to greenhouse gas emissions, particularly methane. These emissions stem from processes such as enteric fermentation in ruminants, rice cultivation, and synthetic fertilizer use.

Each of these sectors faces unique challenges in the path to decarbonization. They require tailored solutions and technological innovations to reduce their carbon footprints effectively. The next sections will delve into the potential role of green hydrogen in these hard-to-abate sectors.

3. Green Hydrogen Production

The promise of green hydrogen lies in its clean production process. Unlike other types of hydrogen that require fossil fuels, green hydrogen can be produced using renewable energy sources, eliminating greenhouse gas emissions. This section outlines the key methods for producing green hydrogen, including electrolysis of water, solar-driven production, and using biomass. It will also discuss current costs and efficiency rates.

3.1 Electrolysis of Water

The most common method of producing green hydrogen is through the electrolysis of water. In this process, an electric current is passed through water, resulting in the separation of hydrogen and oxygen atoms. When the electricity used in this process is derived from renewable energy sources, the resulting hydrogen is considered “green.” The most common types of electrolyzers are alkaline electrolyzers, proton exchange membrane (PEM) electrolyzers, and solid oxide electrolyzers, each with its own strengths and weaknesses.

3.2 Solar-driven Green Hydrogen Production

Solar-driven green hydrogen production, also known as photoelectrochemical (PEC) water splitting, uses sunlight to generate the electrical energy required for electrolysis. In a PEC cell, a semiconducting photoelectrode absorbs solar energy and uses that energy to split water molecules into hydrogen and oxygen. This method is currently less mature than traditional electrolysis but holds promise for efficient, cost-effective green hydrogen production in the future.

3.3 Biomass to Green Hydrogen

Green hydrogen can also be produced from biomass – organic matter like plant and animal waste. In this process, steam reforming or gasification is used to convert biomass into a gas composed primarily of hydrogen and carbon dioxide. The carbon dioxide can then be separated to produce pure hydrogen. While this method isn’t entirely emission-free, it can be considered a low-carbon method, especially when the biomass is sourced sustainably and the carbon dioxide is captured and stored or used.

3.4 Current Production Costs and Efficiency

As of 2023, the cost and efficiency of green hydrogen production vary depending on the method and location, among other factors. Electrolysis is currently the most mature and widely used method, but it requires significant energy input and is sensitive to electricity costs. Therefore, in regions where renewable energy is cheap and abundant, green hydrogen can be produced at a lower cost.

Biomass to green hydrogen and solar-driven green hydrogen production are less mature technologies and currently more expensive. However, ongoing research and development in these areas hold the promise of increased efficiency and lower costs in the future.

It’s also worth noting that green hydrogen production’s costs are expected to decrease in the coming decades due to technological advancements, increased scale, and the declining cost of renewable energy. However, significant investment in research and infrastructure will be needed to achieve these cost reductions.

4. Role of Green Hydrogen in Hard-to-Abate Sectors

Green hydrogen, given its versatility and potential for zero-carbon emissions, can play a critical role in decarbonizing hard-to-abate sectors. This section will explore the potential applications of green hydrogen in various sectors, including transportation, industrial processes, the building sector, agriculture, and others.

4.1 Transportation Sector

In the transportation sector, green hydrogen can serve as an alternative fuel source for vehicles where electrification may not be feasible or efficient, such as heavy-duty trucks, ships, and airplanes. Fuel cell vehicles, which use hydrogen to generate electricity within the vehicle, emit only water vapor, making them an attractive option for reducing carbon emissions.

Moreover, the high energy density of hydrogen makes it suitable for long-haul transport and aviation where weight and volume are critical considerations. However, challenges such as building the necessary fueling infrastructure and improving the energy efficiency of fuel cells remain.

4.2 Industrial Processes

Green hydrogen can be utilized in a variety of industrial processes, either as a feedstock or a fuel. For instance, in steel production, green hydrogen can replace coking coal as a reducing agent to produce “green steel.” Similarly, in the chemical industry, green hydrogen can be used in the production of ammonia, methanol, and other chemicals, reducing reliance on fossil fuels.

However, integrating green hydrogen into these processes may require significant changes in current industrial operations and technologies, which would need substantial research, development, and capital investment.

4.3 Building Sector

In the building sector, green hydrogen can be used in fuel cells to generate heat and electricity. This is particularly useful in areas where it’s difficult to fully electrify the heating system or where the electric grid is not reliable or robust enough to handle peak loads.

Green hydrogen can also be blended with natural gas for use in existing gas networks, reducing the carbon intensity of heating in residential and commercial buildings. However, the viability of this approach depends on the compatibility of existing infrastructure with hydrogen.

4.4 Agriculture

Green hydrogen has potential applications in the agricultural sector as well. It can be used to produce ammonia, a key ingredient in fertilizers. Moreover, it can potentially replace diesel in farm machinery, contributing to the reduction of greenhouse gas emissions in agriculture.

Additionally, using green hydrogen as an energy storage medium can enable off-grid power supply for remote farming operations, leveraging excess power from local renewable installations.

4.5 Potential Applications in Other Sectors

Green hydrogen could also be utilized in other sectors. In the power sector, it can act as a form of energy storage, absorbing excess power during periods of high renewable energy production and delivering it back to the grid when needed.

In the waste management sector, hydrogen fuel cells could be used to power waste collection vehicles, and hydrogen could be produced from organic waste through the process of gasification.

Overall, while there are numerous potential applications for green hydrogen across various sectors, realizing its full potential will require significant technological advancements, supportive policy frameworks, and substantial investments in infrastructure and research.

5. Case Studies

To better understand the potential and challenges of green hydrogen in hard-to-abate sectors, it’s helpful to examine real-world case studies. These examples illustrate where and how green hydrogen has been implemented and provide valuable lessons and success stories.

5.1 Implementations of Green Hydrogen in Hard-to-Abate Sectors

  1. Hydrogen-Powered Trains in Germany: In 2018, Germany introduced the world’s first hydrogen-powered trains, known as Coradia iLint, designed by Alstom. The trains are powered by fuel cells that combine hydrogen and oxygen to produce electricity, with water and heat as the only byproducts.

  2. Green Steel in Sweden: Swedish company SSAB, in collaboration with LKAB and Vattenfall, initiated a project named HYBRIT with the aim of producing fossil-free steel using green hydrogen. As of 2021, they produced the world’s first fossil-free steel.

  3. Port of Los Angeles, USA: Toyota and Kenworth have deployed a fleet of 10 heavy-duty, zero-emission, hydrogen fuel cell electric trucks as part of a project at the Port of Los Angeles. The trucks are used to move goods around the port and to nearby rail yards and warehouses.

5.2 Lessons Learned and Success Stories

Each of these case studies provides valuable insights:

  1. Germany’s Hydrogen-Powered Trains: The trains’ successful operation demonstrates that hydrogen can be a viable alternative to diesel for rail transport. It also illustrates the importance of infrastructure, as hydrogen refuelling stations had to be developed along the train routes.

  2. Green Steel in Sweden: The HYBRIT project shows that green hydrogen can replace fossil fuels in steel production. However, it also demonstrates the need for considerable energy inputs, emphasizing the importance of affordable renewable energy for producing green hydrogen.

  3. Port of Los Angeles, USA: This case study underscores hydrogen’s potential in heavy-duty transportation. But, it also highlights challenges regarding the availability and convenience of hydrogen refuelling stations for vehicles, an area where more infrastructure development is needed.

These success stories and lessons learned emphasize that while green hydrogen has significant potential, realizing that potential will require overcoming technical and infrastructure challenges, as well as ensuring the availability of affordable renewable energy.

6. Current Barriers to Adoption

While green hydrogen holds considerable potential for decarbonizing hard-to-abate sectors, various barriers currently hinder its widespread adoption. This section will discuss the primary technological challenges, economic factors, regulatory and policy issues, and infrastructure and logistical constraints associated with green hydrogen.

6.1 Technological Challenges

Although the basic technology for green hydrogen production exists, several challenges remain. Electrolysis, while well-understood, requires further efficiency improvements and cost reductions to be economically competitive. Similarly, fuel cell technology, used to convert hydrogen back into electricity, needs improvements in durability, power density, and cost. Also, storage and transportation of hydrogen can be challenging due to its low energy density at ambient conditions and reactivity with common materials.

6.2 Economic Factors

Green hydrogen is currently more expensive to produce than other forms of hydrogen and most fossil fuels. The high costs are largely due to the expenses associated with electrolysis equipment and the electricity required for the process. To compete with traditional fuels and other forms of renewable energy, these costs will need to be reduced significantly.

6.3 Regulatory and Policy Issues

Regulatory and policy barriers can also hinder the adoption of green hydrogen. For example, existing regulations may not accommodate the use of hydrogen in certain applications, such as blending into natural gas pipelines. Furthermore, there may be insufficient incentives for investing in green hydrogen technologies, infrastructure, and market development. Clear, supportive policy frameworks will be crucial in driving the transition to green hydrogen.

6.4 Infrastructure and Logistics

Current infrastructure for hydrogen production, storage, transportation, and end-use is limited and will need significant expansion to enable wide-scale green hydrogen use. This includes the need for more electrolysis facilities for production, pipelines or other transportation methods, storage facilities, and fueling stations for end users. Building this infrastructure will require large capital investments and careful planning.

7. Potential Solutions and Future Prospects

Overcoming the barriers to green hydrogen adoption will require targeted solutions and strategies. These can include technological innovations, economic incentives, policy measures, and infrastructure development.

7.1 Technological Innovations and Developments

Advancements in electrolysis technology, fuel cell technology, and hydrogen storage can significantly reduce the costs and improve the efficiency of green hydrogen production and use. Research and development (R&D) should be prioritized in these areas, with partnerships between industry, academia, and governments to accelerate progress.

7.2 Economic Incentives and Funding Opportunities

To make green hydrogen economically competitive, financial support may be needed in the form of grants, loans, tax incentives, or carbon pricing mechanisms. Additionally, funding opportunities can be created for R&D in green hydrogen technologies and for pilot projects in hard-to-abate sectors.

7.3 Policy Recommendations

Policies should be implemented to support the green hydrogen industry. These could include standards for green hydrogen certification, regulations to allow hydrogen blending into natural gas pipelines, and targets for green hydrogen use in different sectors. International cooperation on policy development can also help drive global progress.

7.4 Infrastructure Development

Investment in hydrogen infrastructure will be key to enabling widespread green hydrogen use. This could involve building more electrolysis facilities near renewable energy sources, developing hydrogen transportation and storage infrastructure, and increasing the number of hydrogen refueling stations.

8. Conclusion

Green hydrogen offers a promising pathway to decarbonize hard-to-abate sectors and achieve global climate goals. However, there are significant challenges that must be addressed.

8.1 Summary of Key Points

Green hydrogen can be produced using renewable energy and has potential applications in sectors such as transportation, industry, buildings, and agriculture. Case studies have demonstrated its feasibility, but there are still barriers related to technology, economics, policy, and infrastructure.

8.2 Future Implications

Despite these challenges, the future of green hydrogen looks promising. With technological innovations, economic incentives, supportive policies, and infrastructure development, green hydrogen could play a major role in the global energy transition. It has the potential to create new industries and jobs, improve energy security, and reduce environmental impacts.

8.3 Final Remarks

The journey towards green hydrogen is a collective effort, requiring the cooperation of governments, industry, researchers, and society. As we move forward, it’s crucial to continue exploring and investing in this promising technology, with an eye towards a sustainable and decarbonized future.


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  3. Schmidt, O., Gambhir, A., Staffell, I., Hawkes, A., Nelson, J., & Few, S. (2017). Future cost and performance of water electrolysis: An expert elicitation study. International Journal of Hydrogen Energy, 42(52), 30470-30492.

  4. The Hydrogen Council. (2020). Path to hydrogen competitiveness: A cost perspective. Hydrogen Council.

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  6. Alstom. (2021). The Coradia iLint, the world’s first hydrogen fuel cell train. Alstom.

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