The Hydrogen Economy - Is it really an alternative to fossil fuels? A review.

Hydrogen, when produced through the electrolysis of water using renewable energy sources, holds immense promise as a clean energy carrier. In my non-expert way I am trying to sift the various sources to understand and explain the potential and possible issues with hydrogen as an alternative to our present fossil fuel dependence. FACT: we need to wean ourselves off fossil fuels, but is hydrogen the best alternative? Certainly having water vapour rather than CO2 as a byproduct is a major advantage, but what are the technological, energetic and economic requirements? The manufacturing, distribution and application processes each involve several steps, each with its advantages and challenges in both efficiency and cost.?

As of 2022, the global hydrogen market was valued at $155 billion and was expected to grow at an average (CAGR) of 9.3% between 2023 and 2030.?Of this market, green hydrogen accounted for about $4.2 billion (2.7%).?Due to the higher cost of production, green hydrogen represents a smaller fraction of the hydrogen produced compared to its share of market value, estimated at about 1% of total production volume. This hardly represents a major threat to fossil fuels and as most of this hydrogen is utilised in industrial applications adding new volumes for applications will be economically difficult, if not impossible. ?

Government policies and incentives are playing a crucial role in promoting the adoption of green hydrogen technologies. Supportive regulations, subsidies, and carbon pricing mechanisms may encourage investment in hydrogen infrastructure and drive down production costs. However, inconsistent or inadequate policy frameworks may hinder market development and slow the transition to hydrogen-based economies. ?

Present UK commitments (as of August 2021): ?

• We will work with industry to deliver our ambition for 5GW of low carbon hydrogen production capacity by 2030. In doing so, we would hope to see 1GW of production capacity by 2025.?
• We will provide ￡240m for the Net Zero Hydrogen Fund out to 2024/25 for co-investment in early hydrogen production projects. We intend to launch this Fund in early 2022.?
• We will provide up to ￡60 million under the Low Carbon Hydrogen Supply 2 competition, which will develop novel hydrogen supply solutions for a growing hydrogen economy.?
• We intend to finalise the design elements of a UK standard for low carbon hydrogen by early 2022.?
• We intend to provide a response to our consultation on a Hydrogen Business Model alongside indicative Heads of Terms in Q1 2022. We aim to finalise the business model in 2022, enabling the first contracts to be allocated from Q1 2023.?
• We will develop further detail on our production strategy and twin track approach, including less developed production methods, by early 2022.?

Both the EU’s REPowerEU Strategy (forced by the move away from Russian gas) where 40%+ of hydrogen used will need to be green, and USA’s Inflation Reduction Act ?(IRA) are vastly more ambitious. This hydrogen will likely be used primarily for industrial applications (cement, fertilizer production and heavy transport ~25% carbon offset). ?

Hydrogen's flammability and safety risks pose challenges in public acceptance and regulatory compliance. Establishing robust safety standards, guidelines, and risk mitigation strategies for hydrogen production, storage, and transportation is critical for building public trust and confidence in hydrogen technologies. Additionally, increasing public awareness and education about hydrogen's safety features and benefits are essential for overcoming misconceptions and fostering acceptance. But this is no different if we were introducing fossil fuels today to a new market - would we really want to fill our transportation vehicles with highly combustible tanks of fuel??

So what are the processes and applications??

Manufacture of Hydrogen - “Green Hydrogen”?

Electrolysis: Electrolysis is the primary method for producing green hydrogen. It involves passing an electric current through water (H2O) to split it into hydrogen (H2) and oxygen (O2). There are two main electrolysis methods:?

a. Proton Exchange Membrane (PEM) Electrolysis: PEM electrolysis utilises a solid polymer electrolyte membrane to conduct protons. It operates at relatively low temperatures (typically 50-70°C) and is suitable for small to medium-scale applications. Advantages include high efficiency, rapid response times, and scalability. However, the high cost of materials such as platinum catalysts remains a challenge.?

b. Alkaline Electrolysis: Alkaline electrolysis employs a liquid alkaline electrolyte, typically potassium hydroxide (KOH), to facilitate ion transport. It operates at higher temperatures (80-120°C) and is well-suited for large-scale industrial applications. Alkaline electrolysis offers lower capital costs compared to PEM, but it suffers from lower efficiency and slower response times.?

One of the primary challenges in hydrogen production is the energy efficiency of production methods, particularly electrolysis. Despite recent quoted advances, electrolysis processes still require significant amounts of electricity, resulting in higher costs and energy losses. Improving the efficiency of electrolysers and thus reducing energy consumption are essential to enhance the overall energy efficiency of hydrogen production.?

Requirements of a clean water Source: Access to clean water is crucial for hydrogen production. Using purified or desalinated water ensures high-quality hydrogen output but increases operational costs. Alternatively, using wastewater or seawater can reduce costs but requires additional purification steps to prevent electrode fouling and contamination.?

Renewable Energy Integration: Integrating renewable energy sources into hydrogen production processes is essential for achieving carbon neutrality. The use of renewable energy sources such as solar, wind, tidal or hydroelectric power is essential for producing truly green hydrogen. These energy sources provide carbon-neutral electricity, minimizing the environmental footprint of hydrogen production. However, intermittency and variability in renewable energy generation pose challenges to maintaining consistent electrolysis operations.?

Storage and Transportation?

Once produced, green hydrogen must be stored and transported to end-users. Storage options include compressed gas cylinders, liquid hydrogen tanks, or solid-state hydrogen storage materials. Each method has its advantages and limitations in terms of energy density, safety, and infrastructure requirements. Efficient distribution networks, including pipelines or tanker trucks, are necessary to deliver hydrogen to industrial consumers and fueling stations?

Compression/Storage: Once produced, hydrogen needs to be compressed or liquefied for efficient storage and transport. The high cost of?storage and distribution infrastructure remains a significant barrier to widespread adoption. Compression and storage technologies need further cost reductions to compete with conventional fossil fuels. Additionally, establishing a comprehensive hydrogen infrastructure, including production facilities and refueling stations, requires substantial investment and regulatory support. Compressed hydrogen is typically stored in high-pressure tanks at around 350-700 bar, while liquefied hydrogen is cooled to cryogenic temperatures (-253°C) for storage in insulated tanks. Both methods have their advantages and are chosen based on factors such as energy density, safety, and infrastructure requirements, both however are energy intensive.?

Transportation: Transporting hydrogen from production facilities to end-users requires careful consideration of logistics and infrastructure. Several options are available:?

a. Pipeline Transport: Hydrogen pipelines are the most common method for long-distance transport, especially for large-scale industrial applications. However, building and maintaining hydrogen pipelines can be costly and pose safety challenges, particularly regarding hydrogen embrittlement of pipeline materials.?

b. Truck/Rail Transport: For shorter distances or areas without pipeline infrastructure, hydrogen can be transported via trucks or railcars equipped with high-pressure tanks or cryogenic containers. While flexible, this method incurs higher costs and may be less efficient than pipelines.?

c. Ammonia Transport: Another promising option is to convert hydrogen into ammonia (NH3) for easier and safer transport. Ammonia has a higher energy density than hydrogen and can be stored and transported at ambient temperature and pressure. Once delivered to the end-user, the ammonia can be easily converted back into hydrogen through a process called cracking, it can also be used directly in modified internal combustion engines. However, the conversion process adds complexity and cost to the supply chain.?See H2 v's NH3 article.

Delivery to Application:?

a. Fuel Cells: Hydrogen fuel cells are versatile energy conversion devices that directly convert hydrogen and oxygen into electricity, with water as the only byproduct. In transportation, fuel cells power electric vehicles, including cars, buses, trucks, and trains, offering zero-emission mobility with longer ranges and faster refueling times compared to battery electric vehicles. Moreover, hydrogen fuel cells find applications in portable power systems for military, aerospace, and off-grid operations, providing reliable and clean energy in remote locations.?

Fuel Cell manufacturers (Wiki )?

b. Industrial Processes: In industrial applications, hydrogen plays a crucial role as a versatile feedstock and reducing agent. Industries such as oil refining rely on hydrogen for hydrocracking and desulfurisation processes to produce cleaner fuels with reduced sulfur content. Similarly, hydrogen is essential for ammonia synthesis, where it serves as a precursor to fertilisers and various chemical compounds. Moreover, hydrogen's use in metallurgical processes, such as steel production, contributes to decarbonizing heavy industries and reducing greenhouse gas emissions.?

Industrial Hydrogen producers; Reliance, Shell, Linde, Air Liquide and Sinopec are 5 of the largest. All are primarily producing hydrogen from petrochemicals but are shifting some production to green hydrogen – Reliance claims a lead here from biomass sources, and have even produced a H2 ICE vehicle, note not a fuel cell. ?

c. Energy Storage: Hydrogen offers a promising solution for long-term energy storage, enabling the integration of renewable energy sources like wind and solar into the grid. Excess electricity generated during periods of low demand can be used to produce hydrogen through electrolysis, which is then stored for later use. When demand exceeds supply, stored hydrogen can be converted back into electricity via fuel cells or combustion, providing grid stability and balancing power. Hydrogen-based energy storage systems are particularly valuable in remote or off-grid areas where access to reliable electricity is limited.?

d. Heating and Power Generation: Hydrogen's combustion properties make it suitable for heating and power generation applications. Hydrogen can be directly combusted in gas turbines or boilers to produce heat and electricity, offering a clean alternative to fossil fuels like natural gas and coal.

e. Marine Transport: The maritime sector is increasingly exploring hydrogen as a sustainable fuel for ships to reduce emissions and comply with stricter environmental regulations. Hydrogen fuel cells can power electric propulsion systems in ferries, cruise ships, and cargo vessels, offering zero-emission operations with longer ranges and faster refueling times compared to battery-powered vessels. Ammonia emerges as a potential carrier for hydrogen in maritime applications, as it can be produced, stored, and transported more easily than pure hydrogen. Ammonia can be used directly as a marine fuel or serve as a hydrogen source for fuel cells onboard ships, enabling clean and efficient maritime transport while reducing greenhouse gas emissions and air pollution.?

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Conclusions?

In summary, hydrogen's versatility and clean energy attributes make it a promising solution across various sectors, from transportation and industry to energy storage and power generation. Leveraging hydrogen's potential through innovative applications and integration with ammonia as a carrier can accelerate the transition to a sustainable hydrogen economy and mitigate the impacts of climate change.?

HOWEVER, there is a lot of hydrogen already required for?industrial processes, as noted at the start of this essay 99% of present capacity is grey/blue hydrogen. To replace just this with green hydrogen will require leaps in technology in electrolyser efficiency and renewable energy integration. To then add extra commitments to develop new applications such as fuel-cells in automotive or marine transport seems hugely optimistic in the extreme. ?

The development of grey/blue hydrogen from fossil resources is likely to be an interim route to hydrogen use but for Net Zero this needs to be linked with a similar technological leap in carbon capture and storage of the fossil fuel carbon component. ?

Further Reading?

Excellent article on why exporting hydrogen is impractical, a Canadian view. LinkedIn ?

Efficiencies of fuelcell automotive applications, a “thermodynamic non-starter" Paul Martin LinkedIn 2018?

There is a case for using hydrogen in many applications, but Michael Liebreich has developed a priority list LinkedIn ?

Just because hydrogen can do it, it should? Five Hydrogen Myths: Tessa Weiss,?Kaitlyn Ramirez?

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ICNZ and the Scottish Island’s ?

In the Orkney and Shetland Islands, renewable energy integration with hydrogen production has been a focal point due to their abundant natural resources, including wind, tidal, and wave energy. These islands?have become testbeds for innovative renewable energy projects, showcasing the potential of hydrogen as a clean energy carrier. Here are specific examples and information regarding renewable energy integration in Orkney and Shetland:?

1. Wind Power: Orkney and Shetland are renowned for their strong and consistent wind resources, making them ideal locations for wind energy generation. On Orkney, the European Marine Energy Centre (EMEC) hosts a range of onshore and offshore wind turbines, including experimental floating wind platforms. These wind turbines contribute to the local electricity grid and provide surplus energy for hydrogen production through electrolysis during periods of high wind generation.?

2. Tidal and Wave Energy: The islands' coastal geography offers significant potential for tidal and wave energy generation. Orkney hosts the world's leading tidal energy test facility, the EMEC, which provides a platform for testing tidal turbines and wave energy converters in real sea conditions. The predictable nature of tidal currents and waves aligns well with hydrogen production, as excess renewable energy can be utilised for electrolysis to produce hydrogen during peak generation periods.?

3. Hydrogen Production and Storage: Several projects in Orkney and Shetland demonstrate the integration of renewable energy with hydrogen production. For instance, the Surf 'n' Turf project on Orkney combines wind and tidal energy with hydrogen production for local use. Excess renewable electricity generated by wind turbines and tidal turbines powers electrolysers to produce hydrogen, which is then stored for use in fuel cells or as a feedstock for industrial processes. Similarly, the BIG HIT (Building Innovative Green Hydrogen Systems in an Isolated Territory) project on Orkney integrates tidal and wind energy with hydrogen production for heating, transportation, and power generation.?

4. Transportation and Heating: Hydrogen produced from renewable energy sources in Orkney and Shetland is utilised in various applications, including transportation and heating. Hydrogen fuel cell vehicles and buses are being trialed on the islands, demonstrating the feasibility of hydrogen as a clean transportation fuel. (Innovate UK Clean Maritime Demonstration Competition (CMDC4), which focuses on developing a range of clean maritime technologies including electric, hydrogen, ammonia and more, has been awarded. Moreover, hydrogen can be used in combined heat and power (CHP) systems for residential and commercial heating, providing a clean alternative to fossil fuels like natural gas and heating oil.?

5. Export Opportunities: Orkney and Shetland's experiences with renewable energy and hydrogen production also present export opportunities. Excess renewable energy can be used to produce hydrogen for export to mainland Scotland or neighboring countries via pipelines or shipping. Moreover, the islands' expertise in renewable energy technologies and hydrogen systems can be leveraged to develop consultancy services and knowledge exchange programs for other regions seeking to de-carbonise their energy systems.?

In conclusion, Orkney and Shetland serve as pioneering examples of renewable energy integration with hydrogen production, showcasing the potential for clean and sustainable energy systems in remote and island communities. By leveraging their natural resources and expertise, these islands are leading the transition to a low-carbon future and inspiring similar initiatives worldwide.?

I went over the Hydrogen v’s Ammonia in a previous essay ?

?Advantages of Ammonia in Transport: ?

• High Energy Density: Ammonia has a higher energy density by volume than hydrogen, making it more efficient for storage and transportation, especially over long distances or in areas lacking hydrogen infrastructure.?
• Existing Infrastructure: Ammonia has well-established production, storage, and transportation infrastructure, primarily used in the agricultural and chemical industries, which can be repurposed for ammonia-based fuels.?
• Stable at Ambient Conditions: Ammonia remains in liquid form at ambient temperature and moderate pressures, simplifying storage and handling compared to hydrogen.?
• Low-Cost Production: Ammonia can be produced economically from readily available feedstocks such as nitrogen and hydrogen, particularly through methods like steam methane reforming or electrolysis.?

Disadvantages of Ammonia in Transport:?

• Energetic Efficiency: Ammonia requires additional energy for synthesis and conversion back into hydrogen, reducing overall energy efficiency compared to direct hydrogen utilization.?
• Toxicity: Ammonia is toxic and poses health risks if released into the environment, necessitating strict safety measures in handling and storage.?
• Conversion Complexity: Converting ammonia back into hydrogen requires additional infrastructure and technology, adding complexity and cost to the fuel supply chain.?
• Compatibility Issues: Existing combustion engines and fuel cells may require modifications or new designs to accommodate ammonia as a fuel, potentially limiting its immediate applicability in existing vehicle fleets.?

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