Biogas All Stars: Marcello Ambrosio

Reader Contribution by Warren Weisman
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I will continue the step-by-step introduction to home scale biogas for those interested in learning how to make it with my next post. In the meantime, I thought it might be helpful to mix things up with what I call my Biogas All-Stars series. These are posts where I will highlight one of my colleagues in the international biogas community and let them to answer questions about their projects in their own words.

I believe MOTHER EARTH NEWS readers will find this series useful, as it will offer examples of different types of regionally-appropriate digester designs. These All-stars inspire us all with their resourcefulness and dedication, working with locally available materials in often inhospitable – sometimes even dangerous – conditions to build biogas digesters to transform the lives of people who need it most. The Biogas All-Stars do not appear in any order. I would like to begin with one of the most likeable people I have ever met, Marcello Ambrosio, with the Studio Ambrosio Agricultural Consulting, from Italy.

Marcello (pronounced March-ello) and I met in New York City during a conference for Solar CITIES, an international non-profit biogas education and training organization we both belong to. He is a big fan of Western movies, and once worked as a cowboy in Wyoming during a visit to the U.S. When it comes to building biogas digesters, however, he is definitely the Lone Ranger. Usually working by himself, he has single-handedly built digesters as large as 100 cubic meters (26,000 gallons).  

Marcello specializes in the most common type of biogas digester in the world, the Chinese underground pit-type digester. There are an estimated 50 million of these type digesters in China. They are usually built underground for gas production throughout the cold Chinese winters. The advantage of this type is it allows those willing to get their hands dirty an opportunity to trade labor for material costs. With a readily available supply of bricks and mortar, this type of digester can be built for very little money. Building and operating plans for these types of digesters are available in ‘A Chinese Biogas Manual,’ which can be purchased through online book retailers or a free PDF Copy.

Weisman: When did you discover biogas?

Ambrosio: I first learned about biogas in 2006, as a student at the Polytechnic of Turin. After graduation, I went on to work at large, commercial biogas plants in Germany and Luxemburg. These large plants were using a lot of dedicated crops for feedstocks – mostly corn – and I knew there was no way this was sustainable.

Weisman: Describe the first time you created flammable biogas:

Ambrosio: In 2007 I built a small 100 liter (45 gallon) home plant and produced my first flame. I then built a one cubic meter plant (275 gallons), but it did not work very well, especially in winter. I live in the Alps. I then made my first 12 cubic meter plant, which was big enough to produce sufficient gas throughout the winter.


Weisman: What has been your favorite project so far?

Amrbosio: My favorite size is the 25 to 40 cubic meter plants. They are ideal for small farms with a few cows or horses.


Weisman: What advice would you give young people interested in biogas?

Ambrosio: I would say be careful not to think about biogas by itself, but to consider it as one link in a chain of closed loop sustainability. It is just the first step in the management of the organic wastes and soil ecology. It is important to consider every step of this cycle, for example utilization of the byproducts from the biogas process in agriculture. This multifunctional approach has far more value than the flame itself.

Weisman: Anything else you’d like to add for the American DIY community?

Ambrosio: Just be careful with methane from a climate change perspective. If you generate it, it is okay to burn it, but if you release it into the atmosphere 1 cubic meter (35.3 cubic feet) of methane is equal to 23 cubic meters (811 cubic feet) of CO2. The same impact of driving 60 km (27 miles) in a medium-size car. So, when you build it is important to have proper systems with no leakage and to have the digester sized correctly so when we are not home the gas is not released. Otherwise we are solving the problems of waste disposal and nutrient recycling, while adding to a bigger problem, emitting GHG gases.

Weisman: What is your favorite Western movie and why?

Ambrosio:The Good, the Bad, and the Ugly (1966) directed by Sergio Leone. There is just something magic about Western movies. They commemorate a time when there were still some uncharted lands in the West. Going West was a great adventure for the pioneers in search of prosperity and happiness.

I think people today can learn a lot from that pioneering spirit in our thinking, only instead of heading West we now must look outside the box canyon we have become trapped in to find a better way of doing things.

If you have any home or small farm biogas projects in Europe or non-profit projects anywhere in the world you would like to talk to Marcello about, you can email him at

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