Actually, the German-Swiss start-up AgroScience was only researching an environmentally friendly liquid fertilizer. But then, as a by-product, highly pure CO2 was produced – in itself a greenhouse gas. How this can now be useful on a large industrial scale for e-fuel manufacturing.
AgroScience is still largely unknown in the energy industry. Because the German-Swiss start-up actually specializes in the development of climate-friendly processes and products for more sustainable agriculture. One of the main lines of business is the production of environmentally friendly liquid fertilizer that is free of pollutants and does not allow the soil to become acidic. But what does this green thumb have to do with synthetic fuels?
The scientists noticed the answer quite casually. The development initially focused on a very environmentally friendly NPK complete fertilizer, which can be bought in green bottles for indoor plants, for example. NPK stands for the nutrients nitrogen, phosphorus and potassium. The developers came across a relatively simple and sustainable production process, the details of which are still secret but have now been patented. Compared to conventional production, the new two-phase method is said to save around 70 percent energy. Relatively large amounts of CO₂ are produced as a by-product. What initially appears to be harmful to the climate turns out to be an important source of raw materials at second glance.
Clean CO2 as a raw material
In fact, carbon dioxide (CO₂ for short) does not have a good reputation as a greenhouse gas. It is one of the most important elementary components of the global carbon cycle and makes photosynthesis, i.e. plant growth, possible in the first place. In addition, CO₂ is used in industry as a coolant (dry ice), is used in fire extinguishers or as "carbonic acid" in soft drinks.
AgroScience is aware of the industrial importance of the carbon dioxide produced. And in their fertilizer production process, it is even produced directly at the source and in high-purity food quality. The connection to the food and beverage industry is therefore obvious. Agriculture also needs high-purity carbon dioxide – for example for the production of urea. Urea is one of the most manufactured chemicals in the world and the number one nitrogen fertilizer.
E-fuel systems are reporting a great need
With the energy transition, the energy industry is also reporting a great need for high-purity CO₂. Because it is required in large quantities for the production of methane, methanol derivatives and ultimately also for synthetic fuels. The pilot plants for the e-fuel production of Porsche in southern Chile or Texas already require many tons of carbon dioxide, although mass production has not even started (more about the e-fuel pilot plant in Chile in the gallery).The carbon dioxide, which liquefies from a pressure of 5.2 bar, is currently delivered by truck.
The ideal idea of e-fuel production would be to filter the carbon dioxide from the ambient air in order to remove the CO2 from the atmosphere, which the later combustion process releases again. But since the air in the earth's atmosphere consists of just 0.04 percent by volume of CO₂, gigantic quantities of it have to be sucked in in so-called direct air capture systems, cleaned and catalytically "washed" in a complex and complex manner. That alone costs a lot of energy and worsens the balance sheet. In a study from 2018, scientists assume that at least 250 kilowatt hours (kWh) per tonne of CO₂ will ruin the energy balance of e-fuels.
Organic waste as energy storage
Capturing high-purity carbon dioxide as a by-product of a manufacturing process that is necessary anyway is the more effective solution. This has long been the norm when burning lime. So why not also in fertilizer production? Here the CO₂ is even bound in organic substances, so originally it also comes from the atmosphere. The technology was developed by the engineers at AgroScience - even if the secret organic raw materials have not yet been made public. "But they are readily available everywhere," one of the company's founders assured us.
He reveals a detail in an interview. About 1.0 kilograms of fertilizer and 0.2 kilograms of high-purity, "green" CO₂ are produced from 1.2 kilograms of organic raw material (educt), which can be compressed and liquefied directly. A pilot plant in the vicinity of a modern hydrogen and natural gas infrastructure could therefore create a simple bridge to the energy industry. This is exactly what could happen in north-eastern Germany near the PCK refinery in Schwedt. After all, the major investor Verbio wants to turn the site into the largest bio-refinery in Europe. If the plan works, AgroScience should become better known in the energy industry.
The German-Swiss start-up AgroScience has developed an environmentally friendly process for producing fertilizer that produces food-grade CO₂ as a by-product. This allows green and high-purity carbon dioxide to be produced economically and on a large industrial scale. This is not only interesting for the food and chemical industry, but could also be important for the energy sector and e-fuel manufacturers. A pilot plant is currently being planned.