The header picture shown above may say it all. On the left, perhaps in a near-term sustainable future, a biodigester metabolizing biomass and thereby releasing ammonia which was previously encased in biological construct. This ammonia is a new breed of “Green Ammonia”. The one on the right, an early 20th Century “miracle” technology that was highly credited with enabling civilization to mass-produce a vital fertilizer, ammonia, that has been key for modern agriculture. The process and its product enabled society to hyper-produce food and feed burgeoning populations. Civilization still needs the product, but the means of manufacturing is now a technological oxymoron in today’s reality of heightened sustainability sensibilities.

The Haber Process, the primary method for producing ammonia for agriculture, once viewed as a miracle that was largely responsible for the productivity of modern agriculture, has become a trite anachronism in today’s sustainability era. It consumes 5% and 2% of the world’s natural gas and energy, respectively. It is solely responsible for over 1% of the world’s GHG emissions. These statistics will only worsen as Asian middle classes grow which exacerbates demand for agricultural goods worldwide which then drives increasing demands for ammonia fertilizers. But there is a solution.

The good news is that the technology exists and has been deployed and proven as full capable and scalable for mass production of green ammonia.

It is also interesting to note that many groups have initiatives to deploy ammonia energy production and storage systems.

There is a significant missing piece to having an energy economy that is largely decarbonized using an ammonia-based energy ecosystem instead of one that is carbon-based. One needs to have a reliable and scalable means of green ammonia production. This consideration segues to the better news that green ammonia production systems that are truly renewable already exist and are proven technologies with years of operating experience. This bioconversion technology’s “time has come” with the advent of renewed interest in ammonia energy systems and the considerable positive economic and sustainable impacts that can be realized with these systems in both agriculture and energy production. More details are provided below.

The Haber Process – The Good, the Bad, and the Ugly

UK Haber Fertilizer Plant

This process, also known as the Haber-Bosch process, takes atmospheric nitrogen, and under extreme reaction conditions of temperature and pressure, makes ammonia. The hydrogen source for the reaction comes from methane which is the main constituent of natural gas.

The Good

The good feature of this process is that it makes synthetic ammonia using atmospheric nitrogen and methane. It is largely credited with feeding about one-half of the world’s population.

The Bad

There are a plethora of bad features including egregious energy usage. GHG emissions for the Haber process for ammonia production are about 3 tons of CO 2 /ton ammonia produced. Since the worldwide demand for ammonia fertilizer is so large, synthetic ammonia is responsible for about 1% of all the GHGs produced in the world. Additionally, because the hydrogen source for the Haber reaction comes from methane, synthetic ammonia production consumes an astonishing 5% of all the world’s natural gas.

The Ugly

Unfortunately, the synthetic ammonia saga gets worse. It is notable that the nitrogen source for synthetic ammonia is atmospheric nitrogen. Since the 1950s, the Haber process went into worldwide deployment with large-scale production of ammonia. The nitrogen in the atmosphere is now being transported into soils creating large “nitrogen footprints” in many countries. These large excessive amounts of nitrogen stimulate soil microorganisms to consume carbon in the soil which impact the quality and productivity of the soil. Ammonia has become the poster child for fossil fuel fertilizer and its long-term production is unsustainable in numerous ways. As the demand for agricultural products and the competition for resources needed to make those products increases, production costs will inevitably rise.

Although environmental reasons are compelling for finding replacements or new sources of ammonia, the death knell for the Haber process will ultimately be due to economic reasons as this technology is sustainably obsolete.

Green Ammonia is the Answer

The European Union (EU) has a plan to make “green ammonia” by using electrolyzers to make the hydrogen required to make the ammonia. Their hope is to make perhaps 10% of the required ammonia for the EU by 2030. Other groups are hoping to make low temperature synthesis feasible while a team led by Siemens is trying to make efficient technology that can decarbonize energy systems using another electrolyzer-based green ammonia production platform as shown below.

Siemens Concept for Green Ammonia

All these groups are chasing the grand prize that involves finding a sustainable alternative to the Haber process. Clearly, there is heightened awareness on the potential large role that ammonia can play in sustainable systems. The big question is how to find or make the amounts of green ammonia that enable society to make it a major player in sustainable systems. The stakes are large in this quest. Green ammonia can potentially play many roles in a sustainable economy because it brings numerous advantages including:

It contains no carbon so and it will not produce greenhouse gases when used for energy production.

It can be effectively made with biological processes which rely on a highly efficient enzyme chemistry for catalysis. These processes are proven and scalable.

The infrastructure for an ammonia distribution system is largely in place. This infrastructure is readily amenable to be expanded as needed.

Ammonia can also be readily manufactured from biomass which is a readily renewable resource.

Bioconversion Alternative for Green Ammonia Production

It is commonly known that ammonia and other compounds are readily released as biomass decays. This reaction commonly occurs when biomass is degrade using any number of biological process systems. After ammonia is released, the challenge is to purify it as much as possible. Companies such as Veolia and Ostara remove ammonia in the form of struvite, a compound that is an equi-molar composite of magnesium, ammonia, and phosphate. It is also feasible to design systems for high biomass conversion rates so that ammonia production and harvesting are more economical and scalable.

It is safe to say that biological processes warrant serious consideration for producing green ammonia. A comparison of biological and electrolyzer platforms for green ammonia production is enlightening:

Biological processes leverage the catalytic capability of enzymes which are made by microbes to accelerate reactions. Microorganisms are the world’s most efficient specialty chemical manufacturers and they have a 4 billion year advantage on human civilization concerning developing chemistry for processing biomass and the production of important chemicals. In contrast, electrolysis is a physical-chemical requiring higher energy consumption to facilitate ammonia production.

Biomass feedstocks for the process are plentiful worldwide. Scientists note that countries like the US have huge renewable deposits of biomass that can play a role in deploying an ammonia energy platform. Electrolytic systems are unable to utilize biomass for ammonia production.

Also, there are numerous existing infrastructure installations where ammonia production systems using bioconversion technology can be readily installed similarly to what has been suggested for implementing a hydrogen economy.

The key conclusions from this piece are that there are viable alternatives to the Haber process for producing ammonia. As economic and sustainability pressures increase, society will be economically-drive to consider alternatives. The potential to effectuate a significant decrease in GHG production while at the same time decarbonize our energy infrastructure mandates consideration of resource alternatives such as green ammonia.