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Reimaging Ammonia is Key to Global Decarbonization

Transforming a Major Source of Emissions into a Decarbonization Solution

One of the world’s most important chemicals, ammonia has been widely used as a fertilizer for over a century. Today, its applications are gaining further interest as difficult-to-decarbonize sectors strive to align with net-zero targets. Ammonia is an inorganic compound consisting of nitrogen and hydrogen and is commonly found throughout nature. Easily compressed, stored, and shipped in liquid form, ammonia makes for an excellent energy carrier. And with half the energy density of traditional fossil fuels, ammonia is highly suitable for a wide range of industries. As it stands, roughly 70% of ammonia is produced to be used in agricultural fertilizers, with the remainder going towards industry, including refrigeration, manufacturing, water purification, and pharmaceuticals, among other sectors.

Ammonia is currently produced using the Haber-Bosch method, through which atmospheric nitrogen is reacted with hydrogen under high temperatures and pressures.

This energy-intensive method is responsible for approximately 2% of global carbon emissions. Broad technological advancements, however, have created new opportunities for ammonia to align with net-zero emission targets while helping decarbonize difficult-to-abate sectors. These include:

  1. The elimination of fossil fuels from the ammonia production process, which reduces emissions for ammonia-dependent industries, such as fertilizer and manufacturing.
  2. The development of electrochemical fuel cells that enable the direct conversion of ammonia into electrical power (i.e. using ammonia as an energy carrier)

Electrochemical process development is spearheading these transformative innovations, which are set to drastically impact the ammonia market.

The global ammonia market is set to increase from 80 billion USD in value today to more than 224 billion by 2050, a roughly threefold gain. Spurred by its varied and growing industrial uses and the expanding role of hydrogen-based transport fuels — which are targeting 30% market share by 2050 — ammonia is set to outperform the wider market by a significant margin. Already, multi-billion dollar green ammonia production plants are under construction and targeting operational dates as early as 2026. In addition to providing thousands of jobs to local communities, these projects will help expose investors and governments to the many beneficial applications of green ammonia production.

Decarbonizing Ammonia Production

While ammonia shows promise for global decarbonization efforts, there’s much work to be done to scale up its production in a sustainable manner (e.g. green ammonia). The Haber-Bosch process that currently dominates ammonia production is a major source of carbon emissions, as the necessary feedstock, hydrogen, is produced through steam methane reforming or coal gasification. These fossil-fuel-based techniques produce what is colloquially referred to as “gray ammonia” — similar to hydrogen’s color classification system — and are responsible for a greater share of global emissions than the overwhelming majority of nation states.

When combined with carbon, capture, usage, and storage technologies (CCUS), gray ammonia becomes “blue ammonia,” which has moderately reduced environmental impacts but massively increased costs and project complexity. This trade-off has limited its feasibility so far. Additionally, as fossil fuel inputs are key to blue ammonia production, upstream externalities including carbon emissions remain of chief concern.

In sharp contrast with carbon-intensive varieties, “green ammonia” production relies on renewable electricity. Electrolysis is first used to produce hydrogen by splitting water molecules, after which nitrogen is extracted from the air. When reacted together under high temperatures and pressures using the industry-standard Haber-Bosch process, the elements combine to form green ammonia, which is then ready for transport or combustion.

However, we can take the current green ammonia production process one step further to make it even more sustainable. Instead of using the Haber-Bosch process, nitrogen and hydrogen can be combined using an electrochemical process, eliminating the need for high temperatures and pressures while enabling the distributed production of ammonia closer to point-of-use. This approach promises to further reduce emissions from ammonia by addressing process energy requirements and enabling a more efficient supply chain.
Concurrent with significant advances in the decarbonization of its production, ammonia has gained traction as a carbon-free energy carrier both for stationary power generation and as a marine fuel. Substantial technological advances in the efficient extraction of power from ammonia will enable expanded use cases beyond fertilizer and drive additional decarbonization.

Using Ammonia as a Carbon-free Energy Carrier

As an energy carrier, green ammonia can store and release hydrogen in a convenient and transportable form. Once shipped (usually in liquid form) to its end location, it can be broken back down into its constituent parts — hydrogen and nitrogen — in a catalytic furnace through a process called thermal cracking. The hydrogen is then ready to be used in conventional fuel cells for a range of industrial applications.

Though the economics of green ammonia as an energy carrier are far preferable to shipping hydrogen — primarily due to its low density and high volatility — ammonia is not without challenges. Thermal cracking, which enables the extraction of hydrogen from green ammonia, is energy-intensive, averaging around 0.30 MWh per ton of production. Combined with conversion losses, overall hydrogen output is reduced by more than 25% when converted from ammonia, a significant loss in terms of the scale needed for industrial applications. Additionally, residual ammonia — even in trace amounts — can irreversibly damage hydrogen fuel cells, increasing the risk of technical failure.

Direct Ammonia Fuel Cells

In its current state, the inefficiency of thermal cracking renders green ammonia cost-prohibitive as a clean energy carrier. An emerging process that’s attracting the attention of both governments and the private sector utilizes ammonia in specialized fuel cells to directly generate electricity. Capable of delivering reliable and clean power without the need for co-firing or initial thermal cracking, there is huge potential for direct ammonia fuel cells to decarbonize hard-to-abate sectors, including trucking, marine shipping and power generation for regions with limited potential for solar and wind deployments. Importantly, the ability to forgo thermal cracking – running directly on ammonia as opposed to the hydrogen derived from it – enables greater efficiency while eliminating the risk of hydrogen fuel cell damage.

The two dominant strands of direct ammonia fuel cells are low-temperature membrane and high-temperature solid oxide, both of which are effective but differ in their capabilities and limitations. Low-temperature cells deliver rapid startup and response times, broad material compatibility, and better leverage investments in water electrolyzer and hydrogen fuel cells manufacturing, but face the risk of ammonia crossover contamination as a result of membrane vulnerability. High-temperature cells, on the other hand, are safer from contamination but face significant challenges related to thermal management and manufacturing costs. Both varieties are innovative and highly promising to the growth of green ammonia utilization.

A New Approach to Engineering & Development That Can Scale Green Ammonia Use Cases and Adoption

The current approach to electrochemical ammonia production and fuel cell technologies suffers from a severe lack of intra-industry collaboration and is riddled with inefficiencies. Technology developers have a tendency to focus on single, discrete products like catalysts, reactors, or membranes, with few able to provide holistic system optimization. This value chain fragmentation interferes with industry transparency, causing unnecessary and inefficient duplication efforts and is ultimately failing difficult-to-decarbonize sectors.

For instance, the process of discovering suitable ammonia oxidation electrocatalyst materials for direct ammonia fuel cells — and optimizing them in tandem with better membranes with low ammonia crossover — simply takes too long, with information silos and competitive secrecy further obstructing innovation and development.

Fortunately, new industry ecosystems characterized by deep collaboration between technology developers, manufacturers, project developers, and system operators have emerged to streamline the development of novel electrochemical systems and deliver solutions at scale. These collaborations produce systemic and holistic understandings of green ammonia production and direct ammonia fuel cells in a fraction of the time of conventional R&D in order to facilitate the rapid innovations needed to tackle global decarbonization.

By breaking down barriers throughout the electrochemical industry and leveraging a staged approach to ensure the holistic optimization of catalysts, operating environments, and reactor architectures, companies can accelerate best-in-class solutions to drastically reduce innovation cycles and product-to-market timelines.

Key to this progress is the ability for companies to switch between high-throughput experimentation and prototype-scale device integration in tight feedback loops. By enabling the mimicry and miniaturization of real-world systems and conditions, companies can accelerate the discovery and integration of next-generation electrochemical processes, delivering expanded opportunities for deep decarbonization.