Ashes to ashes – the cycle of nature in the biochar combined heat and power plant

“It is a technology of the future. We wanted to consciously take the lead here”, says Tobias Ilg, one of the two operators of the circular power plant Hatlerdorf in Vorarlberg in western Austria, about his ambitious project. At its centre: a biochar wood gasifier with maximum overall efficiency.

Breaking new ground and setting standards in the field of bioenergy – the Ilg brothers from Vorarlberg have big plans. Since the founding of Energiewerke Ilg GmbH, the qualified biomass workers Bernhard and Tobias Ilg have put five biomass heating plants into operation with a total of 9 km of pipeline network, supplying 250 objects with heat. However, their plans do not stop at pure heating plants. The ambitious brothers set themselves the goal of designing a biomass cogeneration plant that, in addition to electricity and heat, also generates biochar in its purest form.

The idea of a circular CHP plant
The circular CHP plant project started in 2014 in cooperation with the Tyrolean company SynCraft, which developed the necessary technology for this new type of plant. Maximum overall efficiency and high raw material flexibility were the main requirements with which they turned to SynCraft.

And indeed: when the power plant went into operation after six months of planning and three months of construction, it quickly became apparent that an overall efficiency of around 85% could be achieved. 30% of this comes from electrical energy, which is fed into the local grid as green electricity, and the remaining 55% from heat. The CraftWERK 700 system works on the principle of a base load power plant and all year round, only produces as much heat as is needed to cover the base load. In the colder months of the year, conventional biomass boilers from the Ilg brothers are switched on to provide the missing amount of heat.

In summer, the CHP plant can take over the heat supply using the waste heat from electricity production. The boilers can be switched off and do not have to run in an inefficient partial load operation. This reduces fuel consumption and emissions.

Biochar wood gasifier with an efficiency of 85%

The heart of the power plant and the particular pride of the Ilg brothers is the biochar wood gasifier “made in Tyrol”, the first wood gasifier of this type used in Vorarlberg. The biochar produced is collected in the CHP plant, mixed with water until it is moist and filled into big bags or containers. It is used in biogas plants or manure pits to control odors and is indispensable for the production of fertile soils such as black earth. This is where the biochar can develop its maximum ecological potential, as it works as a fertilizer store, which can significantly reduce the use of fertilizers. The ashes from the combustion of the wood chips are also fed back into nature’s cycle: as a high-quality organic fertilizer.

Living in the CHP plant

The Ilg brothers were rewarded with the Energy Globe Vorarlberg in spring 2016 for their innovative ideas and willingness to take high risks. Tobias Ilg was also awarded Austrian farmer of the year in 2018 and winner in the “Energy Farmer” category at the same time. “His curiosity can hardly be satisfied; daring to try something new is practically his hobby”, said the jury.

Tobias Ilg is proud of his pioneering project – so proud that he even lives in it. In fact, the living quarters of the Ilg family are also located in the cogeneration plant. “Officially a certain challenge to sleep next to a wood gasifier,” admits Tobias Ilg with a smile. “But noise or dust are not an issue. It’s a very good life here.”

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