Decarbonization: “How we grow things”
I recently finished Bill Gates’ recent book, How to avoid a climate disaster. Having been in the sector, I found the book with relevant facts, framing of the problems (by segments), and the associated opportunities as we tackle 51 Gigatons (Gt) of CO2-equivalent emissions globally. To use the book’s parlance, I’ve spent my career in the areas of ‘How we plug in’, ‘How we get around’, and ‘How we make things’. This post is not about any of these.
Instead this post is about “How we grow things” — aka agriculture and the food systems, which accounts for 19% of the 51 Gt per year problem. I grew up in India, where the green revolution was one of key reasons for ensuring food supply in the 1960s. What also caught my eye from the book was the description of Norman Borlaug and how his discovery of the new variety of wheat resulted in increased food productivity per acre. Good so far. The other factor responsible for ensuring the global food supply is the use of the fertilizers, particularly, nitrogen (N) fertilizers. It’s estimated that GHG emissions from fertilizers is ~1.3 Gt per year. Not so good. This is the global food supply, invisible to most of us and we’ve taken for granted. Having met and seen many food start-up founders (many promising developments), I decided to double click on the fertilizer problem (opportunity).
Globally we use almost 275 million tons of fertilizer to feed the global population of ~7.8 billion, which is expected to be 10 billion by 2050. Of the three fertilizer types, nitrogen is most important for the food supply and also relevant for climate change (other two being potassium and phosphorous). In fact, N fertilizers are ~60% of the fertilizer consumption. N fertilizers rely on a century old Haber-Bosch (H-B) process for ammonia production, an intermediate for N fertilizers. This single process is responsible for ~2% of the world’s energy consumption and 1.4% of CO2 emissions (!). Many of these plants (~300 globally) are centralized and after accounting for transportation and distribution, the CO2 emissions from N fertilizers are estimated to be ~7%.
With 11 million km2 of land worldwide use for growing corps, N fertilizers result in ~1.5 tons of CO2 per acre per year. To put that in perspective, a typical gasoline car — with 22 mpg mileage, 11,500 miles per year, results in 4.6 tons of CO2 emissions per year. Note that this is not a very efficient vehicle, especially with the adoption of electric vehicles as discussed in previous posts. So the CO2 footprint per acre of farmland is similar to that of a car.
Let’s click one more time on one crop: corn, one of the 3 staples. The growing corn, requires 45 million tons of fertilizers, of which ~28 million tons is N. So just corn results in indirect CO2 emissions of ~0.5 Gt per year (of ~37 Gt across all sectors). And this is not even accounting for health risks from air pollution due to farming practices, nitrous oxide emissions (300 times worse GHG impact vs CO2), and runoffs in land and water (~50% fertilizer).
Suffice to say, many opportunities for innovation and improve the status quo; as we’ve seen in other sectors — e.g. adoption of renewable energy, electric vehicles. Like what happened in those sectors from technology development, product commercialization, channel development; we’re seeing similar trends to address the N fertilizer problem. One of the routes — biological, relies on microbes leveraging the tools of synbio, AI/ML, to improve nitrogen fixation. Many companies are working on this pathway, including Pivot Bio, Kula Bio. The other route — electrochemical, as developed by Nitricity, leverages onsite renewable energy for direct nitration and subsequent release of ammonia.
These are only a handful of examples. Having seen and participated in the growth of early technologies, from solar to gene sequencing; I think we’re witnessing the building blocks being put together to have a viable alternative to the H-B process, improving the ag supply chain, and feeding the global population. And in the process, also decarbonize at scale.
