As a farmer, I hope for prosperity and happiness for all with each new year. But I have learned through 70-plus years in agriculture that that hope must be tempered with reality. Writing these articles sometimes feels like I am repeating myself.
Nitrogen-fixing using the Haber-Bosch method is in the news more and more, it seems. If you are a food producer you are no doubt aware of its importance to the well-being of the Earth’s population, yet is notorious for emitting lots of climate warming CO2, which potentially imperils the well-being of the planet’s population.
The Haber-Bosch process for converting atmospheric nitrogen to ammonia, invented in the early 1900s, is responsible for feeding half of the world’s 8 billion people. Or stated another way, half the nitrogen in the proteins, DNA, and other compounds that give us life was sourced synthetically from the air around us, whether we like it or not. On the dark side, Haber-Bosch is responsible for about 1 percent of the world’s CO2 emissions, and uses approximately 2 percent of the world’s energy output.
Some people like to believe organically produced nitrogen could feed the world: It could not. Experts place the maximum population that could be fed organically at 4 billion, and that would require that farmland be expanded and at least a third of it planted to crops that capture nitrogen from the atmosphere.
To make ammonia (NH3) using Haber-Bosch requires capturing nitrogen from the atmosphere and attaching it to hydrogen. This requires high temperature (800 degrees F), high pressure (3000 psi), gobs of energy, and a source of hydrogen. Natural gas is the primary source of hydrogen for ammonia producers. The carbon in that fuel was taken out of the atmospheric CO2 by plants and animals millions of years ago. Its release exacerbates the greenhouse effect that warms the planet.
There are solutions to that CO2 release, but they are expensive and would significantly raise the cost of fertilizer. It can be captured and pumped deep underground, for instance. This requires pipelines to places where it can be safely stored, and energy to get it there. And overcoming the objections of NIMBYs along the way.
Using electricity to split water into hydrogen and oxygen and then combining atmospheric nitrogen (N2) with the hydrogen to form ammonia (NH3), called electrolysis, is an environmentally benign way to produce ammonia and has a long history. The first plant began production in Italy in 1921. Many small plants followed, but went out of favor by the late 1940s, unable to compete with the more economical Haber-Bosch process that used natural gas as the hydrogen source. With the onset of renewable sources of power — wind, solar, hydro, nuclear, geothermal, etc. — experimental plants are popping up around the world. According to the Ammonia Energy Association, electrolysis-based ammonia production capacity was 10,000 metric tonnes in 2020. At the end of 2024, it is an estimated 1 million tonnes. That is still only a drop in the bucket of the approximately 200 million tonnes of current worldwide ammonia production.
A California startup, Nitricity, is using electricity from solar power to break up the N2 molecule and combine it with oxygen from water to form nitric acid. They then add limestone to produce calcium nitrate, the premium of nitrogen fertilizers. It is alkaline, so a good fertilizer for acid soils. It is very water soluble, so a good additive for irrigation systems. Calcium nitrate has been around for decades, but too expensive for widespread use. It remains to be seen if Nitricity can produce it cheaply enough to compete with other pelleted forms of nitrogen.
An environmental engineer at Leiden University in Holland, Robert Istrate, proposes to substitute biomethane for natural gas (which is mostly methane) in the Haber-Bosch method. His argument is that biomethane from the fermentation of manure and plant refuse would just recycle the carbon recently taken from the atmosphere by plants and animals back to the atmosphere, thus being carbon neutral. (An argument that I have made for the recycling of carbon from cow burps to the atmosphere.)
He claims it would even be carbon negative if the CO2 released was captured and pumped underground. But the supply of biomethane is not unlimited.
A possible revolutionary new method of ammonia production is described in the December 13 Stanford Report. Researchers at Stanford University in cooperation with King Faud University of Petroleum and Minerals have come up with a process that makes ammonia at room temperature and low pressures. Air and water sprayed ultrasonically through a fine mesh coated with a catalyst causes small electrical charges to disassemble molecules of water and nitrogen and allow some of the atoms of nitrogen and hydrogen to unite and form ammonia. The process requires little power and results in no pollutants.
If successfully scaled up, what a miracle answer to the polluting, power guzzling Haber-Bosch process! But don’t expect the massive worldwide Haber-Bosch industry to go quietly.
Jack DeWitt is a farmer-agronomist with farming experience that spans the decades since the end of horse farming to the age of GPS and precision farming. He recounts all and predicts how we can have a future world with abundant food in his book “World Food Unlimited.” A version of this article was republished from Agri-Times Northwest with permission.
