2015 August Experiment Week - Biogas, Lime and Straw

Bee Rowan showing the various stabilised samples

A donation from Lush Charity Pot North America supported the Blueprint Experiment Week, August 2015 in Southern Portugal. The purpose of the Blueprint Experiment Week was to explore the synergistic effects of different fields of expertise and experts in offering solutions to meet our basic needs. The main objectives of our time together were to:

  • Develop lime & clay mixtures for creating weather resistant recipes for plasters, renders, cisterns, Biogas plants, pathways & roads, bricks, etc.
  • Test low cost insulation strategies with materials locally available in most developing countries for small-scale biogas systems.
  • Exchange expertise, build community and increase collaboration amongst people from the Blueprint Network.

For 10 days Bee Rowan, T.H. Culhane, Martin Funk, Christoph Ulbig, Dominik Jais and Ruth Andrade supported by a group of Blueprint members, natural builders of Tamera, biogas interns and Global Campus participants co-created the first Blueprint Experiment week.
We tested local clay & lime mixtures to showcase how lime can be a substitute for concrete. A month later, the local team has started to evaluate the appropriate mixtures for making plasters, renders, cisterns, biogas plants, pathways & roads, bricks, etc. 
Bee Rowan's experience, training and methodology will allow us to build different cement-free components within the Testfield I and Tamera and showcase these solutions to the public.

In addition, at Tamera, we have started to use urine, which is collected separately from the dry toilets, as a source for biogas production, since it's rich in nitrogen.

Another aim was to combine Strawbuild’s natural building techniques with sustainable energy supply. The 'strawbale wrap' and 'light straw clay' techniques were used to insulate two different designs of biogas systems built by Solar Cities. A very low cost shrink-wrap insulation also provided additional experimentation opportunity. One key element was the development of temperature monitoring developed and provided by Solar Cities and installed in the different biogas systems at Tamera. From initial data and following Martin Funk’s suggestions, T.H. says: "One of the most interesting observations seems to be that a south facing black IBC with a window and really good insulation is the very best option overall, so I can imagine doing a strawbale or light straw insulated tank with a double pane window and it being perfect for low cost developing areas.” Solar Cities is working on a formal paper publication with the results.
After the experiment week there has been a lot of positive resonance on the IBC Biogas Digesters. After Greece, Martin Funk went to Germany and Italy to accompany Philip Munyasia from OTEPIC. He made a connection to an Italian NGO that invited him to run workshops in Italy and Nepal.
More information on the biogas systems built can be found on the Solar Cities website and on Biogascentral.net .

Please check the videos and resources below.

Here is a video from 2014 showing the different types of small scale systems available at the demonstration site in Tamera, South Portugal.

Here's a video by Serena Aurora on the lime stabilised soil work made during the experiment week. 


Click here for information on stretch-wrap insulation for quick biogas insulation deployment.

Click here for an overview of the biogas systems built.

Click here to download the Stabilised Lime Soil Manual written by Bee Rowan and Strawbuild in partnership with DfID, HANDS and IOM. It is a step-by-step didactic guide with rich illustrations explaining the process. 


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