What are the benefits of Hydrogen and Ammonia as fuels?

What are the benefits of Hydrogen and Ammonia as fuels?

As the world aims to reduce carbon emissions and dependence on fossil fuels, there is a growing focus on alternative energy sources. Hydrogen and ammonia are among the most promising options, providing routes to cleaner, more sustainable fuels. While they face challenges, their ability to decarbonise energy, transport, and industry positions them as key topics in future energy discussions.

The rise of alternative fuels

The move away from fossil fuels is motivated by the urgent need to address climate change, enhance air quality, and bolster energy security. Conventional hydrocarbons emit substantial carbon dioxide and pollutants, which conflicts with long-term climate objectives.

Hydrogen and ammonia are increasingly seen as flexible options in this transition. Both can be generated using renewable electricity, resulting in' green' versions that reduce lifecycle emissions. Hydrogen serves as a clean energy carrier, whereas ammonia provides a dense, storable, and transportable fuel that can either release hydrogen or be utilised directly. Collectively, they demonstrate that the energy transition depends on a diverse range of technologies working together rather than relying on just one.

Hydrogen: the clean energy carrier

A major advantage of hydrogen fuel is its clean burn. Whether used in a fuel cell or combusted directly, it produces only water vapour, making it a zero-carbon substitute for fossil fuels. This property underscores hydrogen's role as a vital element in decarbonised energy systems.

Hydrogen is extremely versatile. It can be used to power fuel cell electric vehicles, serve as backup electricity, heat buildings, and support industrial processes like steelmaking and fertiliser manufacturing. Its flexibility makes it appealing to both advanced and emerging energy markets.

Hydrogen faces multiple challenges. Its storage and transportation are technically difficult due to low energy density in gas form. Methods like compression, liquefaction, or converting it into derivatives such as ammonia increase both cost and complexity. Additionally, green hydrogen production stays costly since it depends on renewable energy for water electrolysis. A key obstacle in the sector is expanding electrolyser capacity efficiently and reducing costs.

Ammonia: a promising Hydrogen carrier

Ammonia (NH₃) provides an alternative yet complementary pathway to clean energy. Its main benefit is its higher energy density relative to hydrogen, especially in terms of volume. Consequently, ammonia is much easier to store and transport, leveraging the existing global infrastructure established through its widespread use in fertiliser manufacturing.

Ammonia has two applications: serving as a hydrogen carrier (decomposed into hydrogen when needed), or being used directly as a fuel. Its direct application is gaining attention for power generation, fuel cells, and engines designed for ammonia combustion.

Perhaps the most promising application lies in the maritime sector. Ammonia for shipping could significantly reduce emissions in one of the most difficult industries to decarbonise. Unlike hydrogen, which is more challenging to bunker in large quantities, ammonia is already traded globally and could be incorporated into port facilities.

However, ammonia carries certain risks. It is toxic to humans and must be handled with care. Burning it can emit nitrous oxides, strong greenhouse gases that need to be managed using after-treatment systems. Additionally, retrofitting engines and developing infrastructure for widespread use involve substantial investment challenges.

Hydrogen vs. Ammonia: a comparative analysis

When you look at hydrogen and ammonia side by side, you'll notice some clear differences that help us understand how they might each be used.

• Energy density: Ammonia offers higher volumetric energy density, simplifying storage and transportation, whereas hydrogen’s lower density requires more complex storage methods.

• Safety and handling: Hydrogen is highly flammable and prone to leaks, while ammonia is less flammable but toxic, requiring strict safety protocols.

• Infrastructure: Hydrogen necessitates new pipelines, storage tanks, and refuelling stations. Ammonia can utilise parts of existing infrastructure from the fertiliser industry but still requires adaptation for energy use.

• Cost: at the moment, both fuels are more costly than fossil options. The cost of renewable electricity highly influences hydrogen production prices, whereas ammonia incurs extra conversion steps, making it more expensive currently.

Ultimately, hydrogen may be better suited for direct energy applications, such as vehicles and industrial feedstocks, whereas ammonia could primarily be used for long-distance shipping and large-scale energy transportation.

Overcoming the hurdles

The future of hydrogen and ammonia relies on overcoming the challenges that currently limit their competitiveness.

Innovations in production are crucial. Globally, electrolysis technologies are being expanded to lower the cost of green hydrogen, and advancements in the Haber–Bosch process, which has traditionally been carbon-intensive, seek to produce green ammonia at a commercial level.

Hydrogen energy storage and transportation solutions are progressing as well. Research focuses on new materials like metal hydrides, carbon-based sorbents, and cryogenic technologies, which could simplify hydrogen handling. Additionally, ammonia transport benefits from updated safety standards and specialised fuel-ready vessels.

Government policies and investments are essential in supporting the transition. Subsidies, carbon pricing, and regulations encourage the adoption of clean energy sources, while public–private partnerships help reduce risks for early projects. Robust policy frameworks are especially vital for creating cross-border supply chains that connect renewable-rich areas with markets that have high energy demand.

The future of Hydrogen and Ammonia

Market growth forecasts for hydrogen and ammonia are notable. Analysts anticipate that global hydrogen demand will increase severalfold by 2050, driven by energy storage, transportation, and industrial applications. Similarly, ammonia demand is expected to rise not only in agriculture but also within the energy sector, especially as international shipping companies set decarbonisation targets.

Several case studies highlight this momentum, with pilot projects in Japan, South Korea, and Europe testing ammonia co-firing in power plants. At the same time, hydrogen fuel cell buses, trucks, and trains are being deployed across cities worldwide. Major export initiatives, like those in Australia and the Middle East, aim to supply green hydrogen and ammonia to Asian and European markets, emphasising the global scope of this transition.

Hydrogen and ammonia each offer distinctive advantages for the clean energy shift. Hydrogen’s flexibility and zero-emission nature make it a strong energy carrier for various sectors, while ammonia’s high energy density and suitability for shipping make it a valuable complement. Although neither fuel is a complete solution, their combined use forms essential components in the transition to sustainable fuels.

As innovations reduce costs and government policies become more supportive, hydrogen and ammonia are poised to play a key role in shaping the future of energy. For policymakers, investors, and industry leaders, understanding their unique benefits and obstacles will be crucial for advancing the shift toward a cleaner, more resilient energy system.