Combination of domestic biogas production, soil-free food growing
and a set of innovative low-impact environmental solutions for local resilience.

What we do

Excessive nutrient run-off results in eutrophication. Eutrophication of the Baltic Sea is considered one of the main environmental hazards in the region. The main sources of excessive nutrient discharge are agricultural fields and municipal sewage systems. 
Image: Sergey Lutchenko, Suderbyn Ecovillage on Gotland

The project is supported by 
​Baltic Sea Conservation Foundation

With the Closed Loop project we aim to develop and construct a functioning prototype of a circular system for small-scale food and energy production, even in cold and biologically sensitive areas.

In contrast with conventional linear agricultural and industrial approaches causing nutrient run-off, the Closed Loop system recycles the nutrients in food and energy production, recirculating them between a biogas digester and soil-free cultivation (aeroponics), using domestically produced renewable energy.  

We are building from scratch a pilot model of the Closed Loop system on the island of Gotland, in Suderbyn Ecovillage. In 2017-18, with the help of external professional expertise, we plan to prepare an online manual for anyone willing to replicate the system as a whole, or in part. Replication of the circular system would close the nutrient cycle and thus decrease local nutrient discharge into the sea. Closed loop systems, based on smart low-tech solutions and local renewables, can help regenerate the ecosystem, maintain health, and significantly contribute to community resilience. 

How we do it

Closed Loop system is the integration of
a) geo-solar Climate Shell greenhouse using smart design and renewable, locally produced energy
b) micro-biogas digester which uses organic waste for energy production
c) aeroponics systems for soil-free plant cultivation

The biogas system utilises organic waste to produce energy, plus generates a liquid nutrient solution as a by-product.
​The Climate Shell provides low-impact support systems.

Climate Shell

The Climate Shell is a geodesic dome greenhouse integrated with a set of low-impact technologies for heating, energy supply, insulation, ventilation, and rain water collection.
The dome allows year-around operation of the closed loop system because of its specific design and domestically produced renewable energy for heating and electricity.


The 10 cubic meter biogas digester in Suderbyn is a Chinese “family-size” design, and is to be one of the first legal biogas operations in Europe. While the technology has a 3000 year history and its use is widely spread outside Europe, it took us 15 months’ worth of applications and dialogue to get permission to start the operation. 

The molds were gifted by American Professor TH Culhane and Solar CITIES network.


The aeroponics system allows the cultivation of greens and vegetables without exploiting the soil, but rather using a nutrient solution transformed into mist and propagated through the roots. In the Closed Loop system, the solution is the by-product of the biogas production. The aeroponics system is set to be designed and constructed in 2017. 
Image of aeroponics:

Smart Support Systems

To have the Closed Loop up and running, we are busy creating a set of support systems all based on low-tech and environmentally-friendly solutions, affordable even for small communities and families. To minimise our dependence on fossil fuels we chose:

– to provide electricity to the system from a self-built Piggott wind turbine;

– to keep the Climate Shell warm in cold months with a Geo-solar seasonal floor, extra hallways and an additional ‘blanket’;

– to provide additional heat for the biogas digester with Jean Pain compost;

– to ensure water supply through a rain water collection system with storage in two underground pools;

– to keep the temperature balanced by developing an appropriate ventilation system;
– to monitor the temperature and humidity in the Dome (under the geo-solar floor and in the Jean-Pain compost) with an online interface.

In nature, dead matter becomes the source of new life
with the help of the sun, air, water and bacteria. 
We want to use the same principle for our food and energy production.

Why it reduces nutrient run-off

The described system addresses three sources of nutrient run-off:

1) Organic waste becomes a valuable input for energy production, therefore potential nutrient leakage from organic waste is prevented. The liquid by-product from the biogas production is used as the main input in the aeroponics system for food production. The system recycles the nutrients instead of allowing nutrient run-off.

2) The aeroponics cultivation system is soil-free and grows plants without aggressive ploughing or spreading fertilizer in sensitive coastal areas, which would leak from agricultural fields into the sea. This directly reduces the main source of nutrient discharge, which is agricultural land.

3) Techniques integrated in the seasonal Climate Shell avoid fossil-fuel emissions in food/energy production. 

Who we are

Relearn Suderbyn is a non-profit organisation working locally and internationally with sustainable development, environmental and social justice. Our areas of work are:1) action research and experimenting for sustainable solutions2) education for youth and adults3) cross-border cooperation, between sectors and countries.

In the project Relearn Suderbyn creates a functoning experimental model of the Closed Loop System. 

Natural Resources Institute Finland (Luke) 
Luke promotes bioeconomy and sustainable use of natural resources. The research and expert activities are founded on broad-based competence. It consists of four research units: Boreal Green Bioeconomy, Blue Bioeconomy,  Innovative Food System, BioSociety. 

In the project Luke helps with analysis and optimisation of model of the Closed Loop System. 

Closed Loop Baltic project is supported by ​Baltic Sea Conservation Foundation which works with of promoting environmental protection and nature conservation in the Baltic Sea Region.

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