Catalyzing Clean Energy: The Role of Hydrogen and Ammonia Technology Processes

Energy and Environmental Harmony

Hydrogen, the most abundant element in the universe, is increasingly recognized for its potential to serve as a clean energy carrier. Hydrogen is a clean energy source that produces no emissions when used, making it a good choice for reducing air pollution. Additionally, it is an abundant energy source that can be produced from a variety of sources such as air, biomass, and natural gas. Unlike fossil fuels, hydrogen combustion only produces water, making it an environmentally friendly alternative. There are two primary methods for hydrogen production: steam reforming of methane, which results in significant CO₂ emissions, and electrolysis, the splitting of water into oxygen and hydrogen using electricity. When this electricity is derived from renewable sources like wind or solar, the result is green renewable energy, such as hydrogen (H₂) gas, which is seen as key to a sustainable energy future. Globally, the majority of hydrogen gas production still relies on natural gas, resulting in significant greenhouse gas emissions. The challenge is to increase the share of green hydrogen to make this energy source truly sustainable and environmentally benign.

The urgency of adopting hydrogen technologies is amplified by the need to meet climate goals set by global agreements like the Paris Accord. According to forecasts from University College London, to limit global warming to 2°C, it is necessary to keep a third of all oil, half of all natural gas, and 80% of coal in the ground by 2050. Achieving these targets requires a shift to renewable energy sources that do not solely rely on the intermittent availability of wind and solar. The transition to hydrogen is also driven by practical needs in the energy market. For instance, the recent energy shortages in the UK, exacerbated by non-wind days in the North Sea, highlighted the limitations of current renewable energy infrastructures and the necessity for alternatives like hydrogen that can provide reliable, continuous power.

Hydrogen gas can be used as an energy source, energy storage, and energy carrier, and also used for infrastructure purposes. This gas is particularly suited for heavy industries and long-haul transport where direct electrification is impractical.  Industries such as steel, cement, and heavy manufacturing, which are significant contributors to carbon emissions, stand to gain substantial benefits from transitioning to hydrogen. For instance, replacing coal in steel production with hydrogen can drastically cut emissions, helping to decarbonize a notoriously difficult sector. Companies like ThyssenKrupp and Salzgitter AG are pioneering the shift to hydrogen-based processes. Similarly, the chemical industry benefits from green hydrogen in ammonia synthesis, reducing the overall environmental impact of chemical production.

Economic and Financial Challenges

The path to a hydrogen-driven future is fraught with technical and economic hurdles. Historically, the perception of hydrogen has been marred by safety concerns, notably exemplified by the Hindenburg disaster. Critics argue that direct electrification may offer greater efficiency for certain applications compared to hydrogen. Additionally, the production of hydrogen is characterized by high energy intensity, necessitating substantial electricity inputs. When sourced from non-renewable energy, this can undermine its environmental advantages. In 2020, producing one kilogram of green hydrogen cost between around $5 and $7. This is significantly higher if the source is coal ($1.00 to $1.80 per kg) and natural gas ($1.40 to $2.40 per kg). The range of cost heavily depends on the location.

Financially, the transition to hydrogen technology requires considerable investment. Currently, there are over 350 large-scale projects worldwide, with total projected expenditures upwards of $500 billion. These projects span various applications from industrial processes to transportation and energy storage, indicating a growing confidence in hydrogen’s role in reducing carbon footprints. The U.S. alone, through a recent bipartisan infrastructure bill, has allocated $9.5 billion towards hydrogen initiatives, including the creation of hydrogen hubs and the advancement of hydrogen transportation and research. This substantial investment underscores the commitment to integrating hydrogen into the national energy strategy, aiming to ensure a stable, reliable energy supply.

The commitment to hydrogen technology is also robust, with countries such as Germany dedicating approximately €7 billion to hydrogen projects. The country committed to establishing a core hydrogen grid extending 1,800 kilometers by 2027-2028 and is boosting its domestic electrolyzer capacity to at least 10 gigawatts by 2030. The project, located near Puerto Llano, Spain, is part of Iberdrola's broader plan to invest €3 billion in hydrogen technology by 2030. The goal is to link renewable energy production directly to hydrogen and ammonia production facilities, enhancing the sustainability of industrial processes.

India's central government has committed a significant investment of (approximately $2.5 billion) to the National Green Hydrogen Mission. This initiative is designed to create export opportunities, decarbonize energy production, and develop local manufacturing capabilities. The ambitious goal is to reduce the production cost of green hydrogen from the current range of $4.5 per kg to about $1.2 per kg. China targeting the deployment of 1 million fuel-cell vehicles by 2030. These investments underscore a strong belief in hydrogen’s capacity to support a low-carbon economy.

Hydrogen and Ammonia Nexus

Hydrogen's potential is limited by its low density at room temperature, which is roughly one-third that of natural gas. This means that hydrogen either needs to be cooled to -250°C to become a liquid or compressed to up to 300 times atmospheric pressure in order to be transported. This introduces significant energy losses in hydrogen production, estimated at about 30% of overall efficiency. Despite these challenges, the energy sector sees hydrogen as an attractive option because, in its compressed form, hydrogen contains approximately 40,000 Watt hours of energy per kilogram, significantly more than the best lithium-ion batteries, which hold about 280 Watt-hours per kilogram.

Ammonia gas has several advantages over hydrogen gas. It is easier to liquefy, requiring only -33°C, and needs to be compressed to just 10 times atmospheric pressure. Additionally, ammonia does not react with steel or leak from containers as hydrogen does, making it a superior carrier. Indeed, ammonia contains 50% more hydrogen by volume than hydrogen itself and converts back into hydrogen and nitrogen when needed without the intense conditions required for storing pure hydrogen gas.

Parallel to hydrogen, ammonia production is undergoing a transformation. Traditionally reliant on the Haber-Bosch process, which is energy-intensive and carbon-heavy. This process is responsible for about 2% of the world's fossil fuels and accounts for 1.2% of global CO₂ emissions. Evidently, this contributes significantly to CO₂ emissions, nitrate pollution, and nitrous oxide emissions. Ammonia is a critical industrial chemical used primarily in agricultural fertilizers and in the manufacture of plastics and pharmaceuticals. With global production exceeding 200 million tonnes annually in a market worth nearly $100 billion and growing. Due to its potential as a clean alternative to fossil fuels, the efficient and environmentally friendly production of ammonia is increasingly vital.

To achieve the vision of fully green ammonia, the industry must transition away from hybrid and conventional plants. The future lies in using electrochemical cells that operate solely on electricity and catalysts to combine air and water components into ammonia. This process does not require the high heat and pressure typical of traditional ammonia synthesis. However, there is a challenge in producing ammonia efficiently at normal temperatures and pressures. Researchers are currently working towards developing a single cell that can effectively produce ammonia under these conditions.

Monash University’s breakthrough in synthesizing ammonia from water and air using renewable energy illustrates the potential for significant reductions in energy consumption and carbon emissions. This method, if scalable, could revolutionize ammonia production and provide a blueprint for clean industrial processes worldwide. This new process, detailed in the online journal Science, has demonstrated ammonia production rates significantly closer to industrial targets than previous attempts at electrolytic ammonia synthesis. The team has established a startup, Jupiter Ionics, which has already attracted $1.8 million in seed investment.

Future Potential

Ongoing advancements in hydrogen production, such as improved electrolysis techniques and the scaling up of infrastructure, are critical. The development of green ammonia as a derivative of hydrogen for easy storage and transport is also a promising avenue, particularly for sectors like maritime shipping, transportation, and heavy industry where traditional battery storage is unfeasible. Whether hydrogen or battery electrification will dominate the future of transport remains to be seen, but the integration of hydrogen into global energy systems represents a significant step toward achieving a sustainable and clean energy future.