The consortium of the EU project SUSTAINGAS "Enhancing sustainable biogas production in organic farming" (1) has published the first working definition (2) of "sustainable organic biogas". It clarifies the features of organic biogas, enables stakeholders to communicate using common approaches and will be a helpful tool in further implementation of the project. This is important for standardising and developing the market in terms of supply and demand.

The definition is included in the SUSTAINGAS consortium's first report, Product Description of Sustainable Organic Biogas (3), which also presents approaches for producing biogas sustainably on organic farms. The product definition is based on consultations with organic biogas farmers from six European countries and a literature study.

Wolfgang Baaske, co-ordinator of the project explains what is behind this definition: "The studies and interviews clearly revealed the key elements of organic biogas production:

1. Biogas production must be treated holistically - both biogas and digestate are produced.

2. Benefits come from using biogas as energy and increased crop yields.

3. Currently some conventional input substrates are allowed in organic biogas production. This percentage must be limited further.

4. It is important that soil fertility be improved and methane emissions are avoided."

The SUSTAINGAS partnership will continue to work on the criteria for sustainable organic biogas production and recommendations for organic biogas standards. Frank Hofman from Ecofys, Germany, says: "To define these criteria, the green house gases emissions from organic biogas, conventional biogas and fossil fuel will be compared. Several other aspects like soil fertility, biodiversity, water quality, and food vs. fuel are also being taken into consideration."

As sustainability includes financial sustainability, the economic benefits and financial strategies for farmers were discussed at the SUSTAINGAS workshop held in October in Berlin. Michael Tersbol from Okologisk Landsforening, Denmark gives more details: "Biogas technology must be suitable for the type of biomass most relevant to organic biogas farmers, who are largely using clover grass as biomass and who need to maintain the quality of the digestate so it can be used as organic fertilizer.

Other substrates must also be sought, and the cost of obtaining them for use as biomass must be taken into account. Our findings show that farmers working together to run an organic biogas plant can reap economic benefits, as farm income can grow through biomass supply and increased yields through the use of digestate as a fertiliser."

During the project a tool to illustrate the economic mutual benefit between biogas and organic farming will be developed.

(1)The project SUSTAINGAS - Enhancing sustainable biogas production in organic farming - is being implemented within the framework of the Intelligent Energy Europe programme. Consortium includes partners from seven different European Countries: Austria, Bulgaria, Belgium, Denmark, Germany, Poland and Spain.

The project SUSTAINGAS aims at promoting sustainable organic biogas production by identifying and analysing the specific characteristics of organic biogas, its market and barriers, its economic viability, in relation to the crop yield and its sustainability; and by promoting best practice examples and a handbook in workshops, online trainings and webinars.

(2) The initial definition: Sustainable organic biogas is biogas produced with substrates mainly originating from organic agriculture, organic food production and/or nature conservation.

Types of substrate used are mainly catch crops, residues from animal husbandry or crop production, material from conservation areas and/or uncontaminated biological residues. The significance of energy crops as substrates is limited since organic biogas aims to have a positive impact on food production, avoiding a competition for land use.

Material from conventional agriculture is limited. The digestate is used as an organic fertilizer in the organic farms' own nutrient cycle. Organic biogas aims to improve soil fertility in organic farming systems. A safe and efficient process with low emissions particularly of methane is essential for the sustainability. Positive impacts are expected on water conservation and biodiversity.