Green Ammonia: Pioneering a Sustainable Future in Food Production

What is “Green Ammonia”?Ammonia is a vital chemical that sustains half of all food production around the world (through the creation of agricultural fertilizer), but the process we use to make it results in significant greenhouse gas emissions. Ammonia, which is made up of nitrogen and hydrogen, requires extreme heat and pressure and large amounts of energy (usually from fossil fuels) in order to synthesize. “Green ammonia” production reduces this reliance on emission-intensive energy by using cleaner hydrogen inputs and processes that require less energy. Green ammonia, while easier on the planet, is a much harder task to accomplish than mainstream methods. In the Haber-Bosch process, the standard industrial procedure used today, high pressure steam is shot at methane or coal, breaking up the components to produce hydrogen and carbon dioxide. This process requires fossil fuels as an input and releases greenhouse gasses during production, making it a significant contributor to climate change. Once the hydrogen is produced, the Haber-Bosch process synthesizes the hydrogen and nitrogen and separates out ammonia using high temperatures and extreme pressure swings, conditions that require large energy input. The Haber-Bosch process is so energy intensive that this chemical reaction alone accounts for about 1% of global annual CO2 emissions!The Chemical with the Biggest FootprintGreen Ammonia aims to reduce reliance on fossil fuels in multiple stages of this procedure through different approaches. Areas of research include creating reactors that convert sunlight and air into hydrogen, binding together the hydrogen and nitrogen under less pressure than nearly 200 atmospheres, and using less pressure to separate the finished ammonia from other residual gasses at the end of the procedure. The Ammonia Separation ChallengeWhile the Haber-Bosh process uses a large pressure change to liquefy ammonia gas, this method, and many current separation techniques, are carbon intensive and not fully compatible with cleaner hydrogen sources. Creating technology that can more efficiently capture ammonia at lower temperatures and pressures would reduce the energy costs of producing ammonia significantly. An added bonus? Downscaled reactors require lower temperatures and pressures, potentially enabling small-scale ammonia production on farms themselves.About Benjamin SnyderBenjamin Snyder is an Assistant Professor of Chemistry at the University of Illinois, where he conducts research combining inorganic, physical, and materials chemistry. He led green ammonia research as an Arnold O. Beckman Postdoctoral Fellow at UC Berkeley, focusing on alternative methods to separate ammonia. For a transcript of this episode, please visit https://climatebreak.org/green-ammonia-pioneering-a-sustainable-future-in-food-production/