By Michael Reese, Renewable Hydrogen and Ammonia Research Lead, UMN West Central Research and Outreach Center (WCROC)
Industrial decarbonization is the process of reducing fossil energy consumption thereby lowering greenhouse gas (GHG) emissions associated with producing various products. This is also known as reducing the Carbon Intensity (CI) of products. One prime example in Minnesota is the drive to reduce the CI of biofuels such as ethanol. A low CI ethanol product carries a premium within the ethanol market. These premiums have become part of the market due to policies in states such as California where they have implemented a low carbon fuel standard (LCFS). Other agricultural-related industries such as food processing companies, some headquartered in Minnesota, are also moving towards reducing their own CI scores in order to respond to growing consumer demands. This drive towards reducing carbon intensity of Minnesota industries is where hydrogen and ammonia produced from renewable resources such wind and solar may play a significant role. There are many Minnesota industries that can be profoundly impacted including agriculture, iron and steel production, transportation fueling (e-fuels), and construction.
The focus of the WCROC renewable energy program is to reduce fossil energy consumption in production agriculture. In doing so, the CI of agricultural commodities will be reduced. In 2013, WCROC established a first-in-the-world wind to ammonia pilot plant. The process uses wind energy to electrolyzer water and pull nitrogen from the air which are then used to produce anhydrous ammonia. Concurrently, WCROC researchers began to audit energy consumption in production agriculture recording energy consumption in crops, dairy, and swine production. As a result of this research, Tallaksen (2016) showed in evaluating fossil energy consumption in the production of corn at WCROC that nitrogen fertilizer was responsible for 36.4% of the fossil energy footprint with grain drying at 41.6%, and tractor / field operations at 13.9%. So in looking to reduce CI of corn, these are the major areas to address and low CI or “green” anhydrous ammonia can impact each area. Perhaps the most direct option is to use low CI or rather “green” nitrogen fertilizer. In this case, anhydrous ammonia produced from wind and-/- or solar is a drop in replacement which is a major convenience to farmers. Subsequently, WCROC also successfully tested a green ammonia-fueled tractor (2019) and grain dryer (2022). The grain dryer burner required minor modifications to combust ammonia while the tractor required more in-depth conversion. However, the end result was the development of a potentially transformational pathway to reduce fossil energy consumption in corn production. Ultimately, by reducing the CI of corn grain; meat, milk, eggs, and bioethanol production all have a significantly reduced CI. When green nitrogen fertilizer such as ammonia is used in the production of small grains, products such as cereal, bread, and beer also have a significantly reduced CI score. As a side note, a large Minnesota-based cereal manufacturer is currently involved in a study in Stevens County using green ammonia produced at WCROC as nitrogen fertilizer on a small grain field. Another interesting development is the potential to use green ammonia and the CO2 produced during fermentation at ethanol plants to produce another popular nitrogen fertilizer in Minnesota – urea. The production of urea is a circular process in which corn is fermented creating CO2. Green ammonia can then be combing with the CO2 to produce urea which can then be used to nourish corn fields. The urea gives off CO2 which the corn plants uptake and the process continues. The bottom line is that green ammonia (fertilizer and fuel) and derivative nitrogen fertilizers such as urea can significantly lower the CI of agricultural products.
The use of green ammonia and urea in agriculture is a gateway to establishing a much broader green hydrogen industry which will transform the carbon intensity of other industries such as steel production and aviation transportation. There are significant efforts already underway to support the development of hydrogen-based technologies such as green iron and steel production in northern Minnesota and Sustainable Aviation Fuel (SAF) production in Greater Minnesota. The National Renewable Energy Lab conducted a study that found Minnesota as the most ideal place to produce green iron and steel. Hydrogen produced from wind or solar can be used to fuel the process of iron and steel making but is also used to chemically reduce iron in the production process. A group of stakeholders is already seeding the possibility of developing a green iron production facility in Minnesota. In addition, the Minnesota Sustainable Aviation Hub has been co-founded by Greater Minneapolis-St. Paul, Delta, Xcel Energy, Eco-Lab, and many others with the goal to establish sustainable aviation fuel production and utilization in Minnesota. These efforts are in response to lower the Carbon Intensity of steel and aviation transportation – two of the largest contributors to global greenhouse gas emissions. Due to these efforts, Minnesota is poised to be a world leader in green hydrogen industries.
The roots of these transformative green hydrogen efforts trace back to the initial wind-to-hydrogen-to-ammonia research at the West Central Research and Outreach Center. The WCROC certainly does lead innovation in agriculture and beyond!