Representational image. Kittisak Kaewchalun/iStock
Ammonia, a key ingredient in synthetic fertilizers, is critical in global agriculture, supporting billions of people.
However, its production contributes significantly to carbon emissions, prompting urgent calls for greener alternatives.
The traditional process of making ammonia involves nitrogen and hydrogen, with hydrogen typically sourced from natural gas.
Environmental engineer Aurelian Istrate states, “Natural gas contains both carbon and hydrogen, but only hydrogen is needed for ammonia. This means that a lot of carbon is released during production.”
The carbon footprint from traditional ammonia production is a pressing concern in the fight against climate change.
Sustainable solution
One promising solution lies in hydrogen production through electrolysis powered by renewable energy.
However, Istrate notes that this method remains expensive and not widely adopted, leaving most ammonia produced through conventional means.
In his research, Istrate proposes an innovative alternative: using biomethane instead of natural gas in ammonia production.
Biomethane, derived from biomass such as food waste and agricultural residues, has the same chemical structure as natural gas (CH₄) but with a significant difference – it is a renewable resource.
When biomethane is used, the carbon dioxide released during combustion was recently captured from the atmosphere during biomass growth through photosynthesis.
“This achieves a balance,” Istrate explains. In contrast, burning natural gas releases CO2 stored underground for millions of years, adding extra carbon to the atmosphere.
Istrate further emphasizes the potential for carbon capture and storage (CCS) technology to mitigate ammonia production’s environmental impacts.
“If instead of emitting this carbon, you capture and store it permanently, you can work towards net-zero emissions or even carbon negativity,” he says. This means that ammonia production could offset more CO2 than it emits.
Net-zero Ammonia
One of the advantages of using biomethane is that it aligns well with existing ammonia production technologies.
Istrate points out that the separation of CO2 is integral to biomethane and ammonia production processes, meaning no new technologies are needed for carbon capture.
In his comparative research, Istrate evaluates three ammonia production methods: conventional processes, electrolysis, and biomethane-based production.
His findings reveal that using biomethane alongside CCS can produce carbon-negative ammonia.
He also delves into a more pragmatic approach, investigating a scenario where natural gas is blended with biomethane.
To achieve carbon neutrality, Istrate discovered that a mix of 44% biomethane and 56% natural gas, combined with carbon capture, would be required.
Economically, biomethane stands out as a competitive option, particularly in the current landscape influenced by high gas prices due to geopolitical tensions like the Russian invasion of Ukraine.
This situation and the cost and inefficiency of alternatives like Direct Air Carbon Capture and Storage (DACCS) position biomethane as a more viable solution.
“You don’t need complex technology like DACCS,” Istrate asserts. “Often, there are simpler solutions that can have an immediate impact.”
Introducing biomethane into ammonia production is one such solution that could significantly lower carbon emissions in the agricultural sector while ensuring a sustainable supply of fertilizers.
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As the world grapples with climate change, innovations like biomethane represent hopeful pathways towards a greener future in ammonia production, reducing reliance on fossil fuels and aligning agriculture with environmental sustainability.
