The Overview
So, when an academic paper [Ref 1] published in Nature Food has the title “Greenhouse gas emissions from nitrogen fertilizers could be reduced by up to one-fifth of current levels by 2050 with combined interventions”, it is necessary to start poking into this statement – where in the world? What fertilizer products? Lowering emissions to one-fifth of current level and getting same yield?
The news release introducing the paper talked of GHG emissions from nitrogen fertilizers: “This is the first time that their overall contribution, from production to deployment, has been fully quantified.” The analysis presented shows that manure and synthetic fertilizers emit the equivalent of 2.6 gigatonnes of carbon per year – more than global aviation and shipping combined.
The reference to “first time” and “fully quantified” refers to life cycle analysis (LCA) and raised an immediate enquiry. The lead author of the paper, Dr. André Cabrera Serrenho, assistant professor in engineering, environment and sustainable development, University of Cambridge, UK, told New AG International via email: “Although there are LCAs for nitrogen fertilizers, these tend to assess the emissions intensity and other environmental impacts of specific fertilizers (e.g., per kg of fertilizer). However, we have never seen the quantification of global flows of fertilizers and their emissions at each stage of their supply chain, in a way that combines all types of fertilizers and sources of emissions, thus avoiding any double counting.”
Once the qualification of “first” has been hurdled, the next claim to look at is that emissions from nitrogen fertilizers could be lowered to one-fifth, or a reduction of 80 percent, in the next 27 years using various interventions.
The article accompanying the release of the paper on the University of Cambridge website said this reduction would incur no loss of production. Was increased food demand factored into the calculations?
Going back to Dr. Serrenho: “The literature suggests that we can globally increase the efficiency of nitrogen use in croplands from current 42 percent to 67 percent by 2050 without loss of productivity. This is what we have considered as the potential for reducing the demand for fertilizers, and therefore it is not based on a calculation we had done ourselves, but what it is claimed in the literature.”
This leads to the nuts-and-bolts question of how to bring about this reduction in emissions. The paper itself states: “Collective actions from all stakeholders are required to bring about the maximum mitigation potentials explored in this work. Policymakers can promote the increase in nitrogen use efficiency and deployment of cost-effective and mature mitigation technologies. These could be achieved for example by taxing food staples with high fertilizer requirements, alleviating taxes for farms with high nitrogen use efficiency, and regulating the production of fertilizers, including the addition of nitrification inhibitors.”
Words such as nitrification inhibitors will be familiar to New AG readers. The words “taxing” and “regulating” might make some uncomfortable, and others nod in agreement. But that is beside the point. The question here is whether it is possible to measure the very thing that is under discussion – namely global emissions due to nitrogen fertilizers. And on top of that, to then make a long-term projection on a global basis. Rather like doing a Rubik’s cube, a positive change in one place, could have an adverse effect elsewhere.
Ferrying fertilizerLet’s look at trade first. Transport emissions were neglected in the Gao and Serrenho paper: “The GHG emissions from the transportation of nitrogen fertilizers are neglected because they have been shown to account for less than one percent of the life-cycle emissions of fertilizers in country-level studies.”
Anywhere from 45-50 million tonnes of urea are typically shipped around the globe per year, and that’s just one nitrogen fertilizer. Solid nitrates are shipped, around 30 million tonnes. Explosive-grade ammonium nitrate (AN) is shipped in smaller quantities for obvious reasons – so more expensive per tonne-mile. (That AN will be needed to mine all those metals needed for electric batteries.) Liquid UAN is shipped from Trinidad to European and North American markets. That’s a lot of water being shipped. So, a question that could be asked with liquid N fertilizers is how to combine that “cost” of shipping water with the opportunity that UAN presents with adding other agricultural inputs into the solution?
Then there’s the detail in accounting for coatings. In the case of urea, this might be sulphur, particularly in regions where there is an abundance of sulphur from the refining industry.
There are other coatings – inhibitors – these are typically applied near to the end-use. Getting consumption data on inhibitors is tricky, so there is the difficulty of knowing how much fertilizer is coated. Where did the inhibitor active ingredient come from? What was its emission profile before coating a fertilizer granule? More questions. A Rubik’s cube isn’t meant to be easy.
How to forecast adoption?The difficulty around emissions is made all the harder since eventually it becomes an exercise in forecasting adoption. Doing that on global scale, even more challenging.
Forecasting the emission reduction efficacy of new technologies is another challenge. That will also involve a battle of claims from various technology providers. Suppliers of precision agriculture equipment (sensors, drones, software) might well argue that their technology will lower emissions by providing more data to farmer. Cutting through the thicket of competing claims will be difficult when making projections.
The difficulty around emissions is made allthe harder since eventually it becomes an exercisein forecasting adoption.
Re-focus on NUEFocusing on nutrient use efficiency (NUE) might be a slightly easier exercise to forecast. The volume of NPK and S can be estimated and the global crop tonnage reasonably reliable – for major crops at least. From there, an efficiency number is possible with a greater degree of confidence for certain regions.
But none of this data would be available in real time. It might be
possible to have a reasonably quick view of a country that is self-sufficient in fertilizer, but these tend to export, so you would need to subtract those exports from the country’s production. And that assumes you know the operating rates of its fertilizer plants.
Whenever you are looking at trade data, for example, that is just a snapshot in time. Actual consumption figures will be delayed, so any nutrient in/nutrient uptake measurements will be around two years after the event. As for the global picture, you are really relying on industry associations collating the data, and organizations such as the FAO.
Getting statistics for fertilizer consumption requires a lot of coordination with associations at the country level. Inevitably, this leads to a top-down approach based on supply and capacity, and general assumptions for production rates. These are just some of the complexities, and that’s before you even get into stock levels.
But let’s imagine you have managed to generate a nutrient use efficiency for most of the globe; you have a good picture of all the major nutrients applied (you are disregarding micronutrients for the moment), and you have an idea of the nutrient content of the crops harvested. You will then have a nutrient use efficiency number. In academic terms, usually written as nitrogen use efficiency = nitrogen output/nitrogen input. But, of course, that’s not the whole story – there is nitrogen uptake efficiency, utilization efficiency and harvest index [Ref 3].
But we are keeping things simple and have imagined that we have derived a percentage. A higher percentage tells you that more of the nutrient is finding its way into the crop, and less is being lost, and in this way can be used to estimate the saving in emissions. In the case of nitrogen, if more of the applied N comes through in the harvested product then less has been lost. And according to the Gao and Serrenho paper, "approximately two-thirds of fertilizer emissions take place after their deployment in croplands."
But what about synergistic effects – where some nutrients help the uptake of another nutrient, such as urea coated with sulphur or zinc. Where will this come on the spreadsheet?
If the name of the game is emission reduction, then simply applying less fertilizer would be one solution,
or increasing efficiency through inhibitors and coatings. The impact on yield shows there is a calculus here to be performed. That’s where statements such as “collective actions from all stakeholders” will mean different things even in neighbouring farms. Economics, as always, will be the key driver of a farmer’s decision making.
And when we say stakeholders, who are they? This could also mean distributors who have a vital role to play in bringing new products to growers and demonstrating their efficacy. Transport and logistics firms similarly have a role to play.
Missing factorThere is one important factor that can often spoil the efforts of forecasters, and that is geopolitics. Ceteris paribus, namely, all other things being equal, is the assumption used in forecasts acting rather like a disclaimer. When a war happens – such as the invasion of Ukraine – there are a multitude of impacts, particularly across the food supply chain. Obviously, it is difficult to forecast a war, and in the practice of forecasting, one often assigns a risk value to certain types of events.
The invasion of Ukraine has contributed to high natural gas prices in Europe, causing the shutdown of some capacity and a struggle for those that continue. At the end of 2022, industry association Fertilisers Europe was critical of the EU Council’s decision to suspend urea and ammonia tariffs saying that the member states of the EU were already “under record surge of imported products. “This decision is at odds with the EU’s policy to reinforce its strategic autonomy,” Fertilisers Europe argued.
On 16 February 2023, Fertilisers Europe then welcomed the EU Parliament’s resolution call for a strategy to boost the EU’s autonomy on fertilizers. “We are pleased to see that the European Parliament’s overwhelming majority recognizes the key role of the fertilizer industry for food production as well as for its
industrial products, such as AdBlue for road transport sector and CO₂ supplies for the beverage and food industry,” said Cecilia Dardes, agriculture and environment manager at Fertilisers Europe. This highlights another point – fertilizers are deeply political. It is not just the food and useful byproducts they produce, they represent jobs, in both production and along the supply chain.
Dardes added: “Regrettably, the resolution does not reflect in a balanced way the importance of mineral fertilizers for the productivity of the EU agriculture. With 50 percent of food produced with the help of mineral fertilizers, organic and mineral fertilization sources must be seen as part of the same puzzle. Mineral fertilizers provide the essential distinct high productivity boost, thus supporting farmers in ensuring balanced plant nutrition and in effect growing high-quality crops.”
With 50 percent of food produced with the help of mineral fertilizers, organic and mineral fertilization sources must be seen as part of the same puzzle.
The view that mineral fertilizers are still very much necessary strikes a chord with the opinion piece in the March 2022 issue of New AG International. Contributing Editor Dr. Oded Achilea presents an argument for mineral fertilizers, and emphasises the importance of nutrient use efficiency, a point that is clearly made in the Gao and Serrenho paper, where it says: “Increasing nitrogen use efficiency is the single most effective strategy to reduce emissions.”
Production cutsAs mentioned above, one way to cut emissions is to apply less fertilizer or shut down production to reduce their life-cycle contribution.
In February 2022, BASF announced it was closing its caprolactam plant, and one of the two ammonia plants and associated fertilizer facilities at the huge site at Ludwigshafen, Germany. Dr. Martin Brudermüller, chairman of the board of executive directors said in the company’s 24 Februrary statement: “Europe’s competitiveness is increasingly suffering from overregulation, slow and bureaucratic permitting processes, and in particular, high costs for most production input factors. All this has already hampered market growth in Europe in comparison with other regions. High energy prices are now putting an additional burden on profitability and competitiveness in Europe.”
Europe’s competitiveness is increasingly suffering from overregulation, slow and bureaucratic permitting processes, and in particular, high costs for most production input factors.
The structural changes will lead to a significant reduction in the power and natural gas demand at the Ludwigshafen site. Consequently, CO2 emissions in Ludwigshafen will be reduced by around 0.9 million metric tons per year. This corresponds to a reduction of around four percent in BASF’s global CO2 emissions, the company stated. BASF added it intended to secure greater supplies of renewable energy for the Ludwigshafen site.
What colour?Renewable fertilizers are very much a talking point at present. From a recent discussion, one contact who had left the ammonia industry for a few years, returned to find things had changed. When he left, there was one type of ammonia he told me, but on his return, there were now three: blue, green, and brown ammonia. The blue and green will play a role in renewable fertilizers. There are more varieties – pink ammonia – to describe ammonia derived from nuclear power, turquoise to describe ammonia from pyrolysis.
In an academic paper published December 2022, Gabrielli and Rosa [Ref 2] presented their analysis showing possible pathways to net-zero fertilizer production. The paper shows decarbonizing ammonia production through the electrification route, using electrolysis, for globalproduction would require 1,219 TWh of electricity, compared to current demand of 48 TWh, a 25-fold increase.
“Transitioning fertilizers to net-zero emissions can contribute to climate and food security goals, although water, land and energy trade-offs should be considered,” the paper noted. Gabrielli and Rosa also calculated that the number of people who are dependent on fertilizer imports or natural gas for fertilizer production: “Our results quantify the reliance of the global food system on synthetic nitrogen fertilizers and natural gas trade. We find that 1.07 billion people per year are fed from food reliant on fertilizer imports. However, when accounting for embedded natural gas imports, or the share of synthetic fertilizers produced from imported natural gas, we find that 1.78 billion people per year are fed from food reliant on imports of either fertilizers or natural gas.”
In the paper’s section on solutions to reduce ammonia demand, the authors cite precision agriculture as one way to increase the efficiency of nitrogen fertilizers application to crops. The paper concludes that the relevance of location-specific analyses when trying to determine the “optimal net-zero routes for producing fertilizers based on technical, environmental and geo-political circumstances.”
Sense of scaleThe words “location-specific” raise the question of scale. Building large-scale centres of fertilizer production based on the ample supply of raw material might be one route to lowering overall emissions. This concept is mentioned in Oded Achilea’s article. The Gao and Serrenho paper estimates that the manufacturing of nitrogen fertilizer is the smaller contributor of emissions, with two-thirds of fertilizer emissions taking place after their application in croplands.
An example of scale is in Brunei. Sultan Haji Hassanal Bolkiah officially opened one of the world’s largest single urea trains at Brunei Fertilizer Industries (BFI) in February 2022. The plant has an annual capacity of 1.36 tonnes/year of granular urea. In operation since January 2022, the plant has exported to regional markets, such as Thailand, Australia and New Zealand.
An idea counter to large scale is small scale. Urea technology provider Stamicarbon, based in the Netherlands, has developed small scale ammonia plants. In 2021, the company announced a project with Argentina-based company Raybite.
Small scale might work for specialty fertilizer using nitrate based on green ammonia. Small and local might be less vulnerable to geopolitical factors, unlike a super-site that might, say, be dependent on one pipeline. Stamicarbon also has a project in Kenya using its small-scale ammonia technology. The project uses geothermal energy, which is already in operation in that part of Kenya (see article here).
Rising thermalsWhen talking about emissions reduction and agriculture, one area to explore is greenhouses or more generally protected cultivation. Growing more food, closer to where it is consumed, and lowering food miles, all sounds promising when reducing emissions, but in cold climates greenhouses require heating. They also consume CO2 to increase plant growth. One way to heat these greenhouses is through natural gas. This was another knock-on effect from the high natural gas prices in Europe.
Geothermal energy might have potential in this regard. In this, the March 2023 issue of New AG International, our editor Janet Kanters looked at whether large-scale greenhouse crop production in Iceland was viable. Iceland is a country with an abundance of geothermal and hydroelectric resources. Looking at a study by researchers at the university at Wageningen, the report stated: “Despite its northern latitude, [Iceland] has some unique characteristics which might make the island a good candidate for the establishment and operation of protected crop production.”
But can Iceland host “giga scale” factories for crop production and export to different world markets? And which crops could be produced competitively at a giga scale? These are just some of the questions to explore.
In the same issue, New AG International also looked at the rapid growth in greenhouse and protected acreage across the globe. Our contributor Matt McIntosh notes that greenhouse expansions are set to continue, but maybe not at the speed of previous decades. In terms of crop types, it is not just the big three: cucumber, pepper and tomato. From berries to Chinese cabbage, one interviewee says greenhouses across North America “are experimenting with an ever-wider range of crops. But while acreage of less traditional crops is increasing, many remain niche products.”
Puzzling timesGrowing more crops under protection or controlled environments might offer one route or solution to emissions reduction and nutrient use efficiency.
But drawing on Gabrielli and Rosa and the idea of trade-offs, it might be that the solution for the Rubik’s cube of ag might only be partial at any moment in time. In a global sense, having all sides of the cube completed might not be realistic. Interconnections mean that as one side is completed another is changed. Trying to forecast that is a whole new puzzle.
References[Ref 1]: Gao, Y., Cabrera Serrenho, A. Greenhouse gas emissions from nitrogen fertilizers could be reduced by up to one-fifth of current levels by 2050 with combined interventions. Nat Food 4, 170–178 (2023).
[Ref 2]: Energy and food security implications of transitioning synthetic nitrogen fertilizers to net-zero emissions. Lorenzo Rosa and Paolo Gabrielli 2023 Environ. Res. Lett. 18 014008.
[Ref 3]: Yara (https://www.yara.co.uk/grow-the-future/efficient-farming/nitrogen-use-efficiency/) ●
Luke Hutson, New AG International Chief Analyst
Getting statistics for fertilizer consumption requires a lot of coordination with associations at the country level
Russian military machinery destroyed during Russia's invasion of Ukraine lays on the agricultural field in Chernihiv area, Ukraine
Courtesy of website Brunei Fertilizer Industries
