Green soils for Ethiopia

For five years, Dr Katharina Prost coordinated the German-Ethiopian cooperation project ClimEtSan on pyrolysis cookstoves, the circular economy and climate-smart agriculture at Forschungszentrum Jülich and in Ethiopia as a post-doctoral researcher. In 2022, the agricultural scientist took the plunge into the spin-off: Building on the results of the research project, her company ClimEtSan-OnTheGround is implementing circular climate protection projects in Ethiopia in order to improve local living and environmental conditions, increase agricultural production and provide sustainable CO2 certificates for the voluntary carbon market.

Let's start with your time at Forschungszentrum Jülich. What characterised it?

I would like to start a few steps earlier - with my diploma thesis. Even as a student, I was fascinated by the ultra-fertile soil in the Amazon region, terra preta, which contains, among other things, biochar. That's why I focussed on the question in my thesis: How can biochar be activated - that is, charcoal made from plant material that is not used for burning, but is used in agriculture, for example? This activation step is necessary in order to maximise its soil improvement potential. We achieved this by hot composting the biochar together with manure. Years later, a lecturer at an Ethiopian university read the publication of these test results and contacted me. This gave rise to the idea of using human excrement as well as animal excrement to produce biochar compost in a joint project, thereby tapping into large quantities of nutrient-rich resources for fertiliser production. Like a godsend, a corresponding call for proposals from the BMBF and the DAAD on sub-Saharan Africa came at just the right time. As my supervisor from the University of Bonn was also a board member of IBG-3 at the research centre, he suggested linking the project with the research centre and the topic of greenhouse gas reduction. So we wrote an application, were able to raise the project funds - and I was the project coordinator of a German-Ethiopian research project for five years. That's how I got to know Ethiopia. In addition to scientific and organisational coordination, my main tasks were to set up demonstration facilities such as pyrolysis cooking oven workshops, ecological dry toilets, composting plants, field trials and laboratories. Ethiopia has since become my second home; the country and its people have captivated me.

How did the start-up
ClimEtSan-OnTheGround come about?

I was very happy and passionate about being a scientist: I particularly liked the working group, the collaboration and the team at the research centre. But you can only stay in science as long as you get follow-up funding. During the research project in Ethiopia, there were travel restrictions from 2020 due to coronavirus and the war in the north of the country at the time. Although the war did not affect our project location, the travel restrictions made our work very difficult. Due to this situation, it was also not possible to obtain follow-up funding for our project - nor would it have been possible to realise this in close contact with the local actors. However, as I wanted to press ahead with the topic and ultimately bring it from research to reality due to the good results, the spin-off was the logical consequence. I decided to do this towards the end of the project - so there wasn't much lead time for the start-up. That was of course very late, but the research centre supported me immediately when I approached them with this idea.

What exactly does the work of your start-up consist of?

Soil fertility is dwindling worldwide. 33 per cent of all soils are already degraded and, according to the Food and Agriculture Organisation of the United Nations (FAO), this figure is likely to rise to 90 per cent by 2050 if current practices do not change. The most important way to restore soil fertility is to build up humus. This is because a well-functioning soil ecosystem that can optimally support our crops can only exist in humus-rich soil. One possible approach to increasing the humus content of soil is to use biochar compost as a fertiliser and soil improver. If biochar is composted together with other waste, an extremely potent fertiliser is created that revitalises the soil quickly and for a long time. The field trials of the ClimEtSan research project in collaboration with a Farmer Training Centre showed exactly this: Our compost was already able to replace mineral fertiliser in the first season - and without any loss of yield. Three years later, it turned out that the areas fertilised with our compost were still green even when everything else was already brown and withered. This is because the biochar compost quickly increases the humus content and - as humus can store up to five times its own weight in water - also increases the soil's ability to store water. This makes them more resilient to the negative effects of climate change such as heavy rainfall or droughts. We obtain the raw materials for the biochar compost from urban waste streams, which consist of up to 80 per cent organic waste, as well as from dry toilets, which we operate without water and with sawdust as bedding. This is because over 90 per cent of people have no access to improved sanitation: With our dry toilets, we can offer low-cost and easy-to-implement solutions.
We obtain the raw materials for the biochar compost from urban waste streams, which consist of up to 80 per cent organic waste, as well as from dry toilets, which we operate without water and with sawdust as bedding. This is because over 90 per cent of people have no access to improved sanitation: With our dry toilets, we can offer low-cost and easy-to-implement solutions.
In short, we link city and countryside: the food is brought from the countryside to the city, where it is consumed, and the waste is turned into fertiliser together with biochar and transported back to the countryside. The biochar we use is produced in very efficient pyrolytic cooking ovens made largely from clay. They were developed and patented by a German clay construction company, and we are building the ovens in Ethiopia in co-operation. To date, over 90 per cent of Ethiopian women cook over a smoky fire. In the pyrolysis stoves, however, the resulting flue gas is burnt, so cooking is smoke-free on a gas flame - what remains is charcoal, which we buy back from the households. The ovens are already in use in 50 households, and this year we want to equip a further 650 households with them.

How is the company financed?

Biochar is made from plants that have absorbed CO2 from the air and used it to build their cell walls, among other things. If the plant material is carbonised, the CO2 - i.e. the carbon now bound in the plant material - takes on a very stable form: it can be stored in the soil for thousands of years. The Terra Preta soils mentioned at the beginning are a good example of this, as they contain pieces of carbon that are up to several thousand years old. We are therefore taking CO2 out of the atmosphere and storing it in the soil - in this way we can reverse climate change to some extent and increase soil fertility at the same time. This is interesting for companies in two respects: with off-setting, they can buy CO2 certificates from us and thus improve their carbon footprint, while we can offer our products in Ethiopia at greatly reduced prices thanks to the co-financing from the sale of certificates. With in-setting, companies that have agricultural supply chains from Ethiopia can use our biochar fertilisers - for example, if they grow coffee in Ethiopia and export it to Germany. This allows them to increase the yields and climate resilience of their production and at the same time have the fixed CO2 in the biochar recognised in their carbon footprint.
The demand for our ovens, toilets and fertiliser is already enormous. However, it takes a lot of time to build up the entire cycle and combine it with CO2 certification. Therefore - as is probably the case with most young companies - perseverance and luck are among the most important components to get through the lean period to sufficient turnover.

Contact:
Katharina Prost

katharina.prost@climetsan-ontheground.com