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Newsletter no7

Final Information about the GR3-project


The final open conference of the GR3 project was sucessfully held on 17th of March 2016 in Ghent (Belgium)

Around 70 stakeholders from 10 different countries were informed about the results of the project at a final open conference in Gent. It was a joint event with the FP7-INEMAD project. Where GR3 is mainly looking at the supply chain to support the use of grass clippings for biogas production, INEMAD is looking at agricultural inputs to produce biogas and biobased fertilizers.

The day opened with a presentation of the President of the European Biogas Association and a short introduction to the possibilities of grass digestion. After that also the environmental and social impact were evaluated and an insight in the (complex!) legal framework on the matter was given. In the afternoon sessions people could work and discuss in smaller groups on the actual output of the project: the results of the inventarisation, the tools that were developed, the technology report and the developed Business Plans. The day ended with an interactive panel discussion on subjects that concerned both projects.

All the presentations of the day are now available on the project's

Final regional GR3-conferences in 4 countries successfully held

At the end of the project four final regional conferences were organized in the countries Germany, Italy, Denmark and Portugal to present the (regional) project results to regional stakeholders. Here are the summaries of these events.


Visitors group at AD plant Battenberg

The final regional conference in Germany was organised by IBBK Fachgruppe Biogas GmbH and took place on February 23rd, 2016. The first part of this one day event was held in a restaurant in Battenberg/Eder. Reknowned speakers gave an overview the project's results as well as perspectives and potential supply chains for grass digestion.

The second part in the afternoon took place on Viessmann's AD dry fermentation plant in Allendorf/Eder. It's speciality is the treatment of an extremely high share of herbacious biomass. During the visit the group gained insight in the challenges of operating such a plant successfully.

Due to the current difficult status of AD in Germany and the uncertain future prospects, the event's organiser was happy to welcome a small, but dedicated, group of 16 stakeholders. They represented five out of six different target groups, coming from "owners of composting and biogas plants" (30%), "supplier of landscape grass" (10%), " constructors of machinery" (10%), "policy and decision makers" (10%) and the biggest group "others" (40%).


The GR3 Italy final Conference titled OPPORTUNITIES FOR THE EXPLOITATION OF RESIDUAL HERBS IN BIOGAS PRODUCTION was held on Feb. 5th within Fieragricola 2016 (Verona - Italy), the most important Italian Agricultural Fair reaching the 112th edition. Practical tips and suggestions which emerged from the project - funded by the Intelligent Energy for Europe programme - has been presented, among others, by Mr. Koettner, CEO of IBBK Fachgruppe Biogas GmbH and one of the most known expert in biogas plant management.

More than 60 people followed the event targeting not only operators of biogas plants but also grass providers such as cooperatives dealing with park maintenance or water management authorities etc. In fact the conference addressed not only the issues concerning the appropriate management techniques for anaerobic digestion plants where the grass can replace most noble and expensive matrices such as maize or sorghum; but it also presented the opportunities for "suppliers" of grass, such as the features required by biogas plants operators, the costs for grass cleaning treatment and other aspects related to logistics.


Speaker at Danish final regional conference
The workshop took place on March 3rd, at the University of Southern Denmark in Odense, from 9.00 to 16.00. A total of 62 participants did attend the workshop. These stakeholders came from all of the defined target groups. The key results of the Danish event are the following:

  • It is difficult to make a positive economy case with grass from nature areas (organic grass excepted). Concrete cost figures were presented (Kurt Gregersen).
  • In Denmark, there is a huge focus on straw and deep litter at the moment, which makes it difficult for grass to compete.
  • The most suitable case is with urban grass (household clippings, parks) that is collected already.
  • A new technology allowing to cut and pre-treat grass simultaneously was presented (Uffe Larsen); results available so far showed up to 35% increase in gas production.


The final regional conference in Portugal took place on March 14th, 2016. This one day event entitled “Opportunities for energetic valorization of green grass waste” was held at LNEG auditorium (National Laboratory for Energy and Geology), with the objective to bring together the main actors and stakeholders with influence on grass valorization and biogas production.

The morning session presented an overview of the results achieved within GR3 project together with four selected case-studies of grass use in AD. Authorities from the energy and environmental sector were invited to explain their position, in-line with the project recommendations. In the afternoon a study visit to the AD plant of TRATOLIXO inter-municipal waste operator, was offered to all the participants.

The event had 109 registered participants (97 attending), coming from commercial or public companies (37 %), R&D institutions (37%), and public organisms, including policy makers (24%), a clear indication of the interest raised by the GR3 project".

All the presentations of these four final regional conferences are either available already on the project website or will be embedded there in the next days!

The grass prediction tool is out now!

Introduction - Explanation of the model:
in the course of the GR3 project a model was designed to determine the biogas production of a single stage CSTR digester with (assumed) perfect mixing. A method for the economical comparison between different feedstocks is constructed based on the characteristics and price of the feedstock, the biogas production in the reactor and the price for the digestate.

Current plant and feedstock characteristics:
On top of the first page, the input page, general information about the plant and the country must be filled in. The volume of the reactor is necessary to calculate the residence time of the feedstock. The price of digestate and biogas are important for the calculation of the economic feasibility of the different feedstocks.

Economic output:
When the biogas potential (BGP) of the feedstock, the price and the cost of the produced digestate are taken into consideration the model compares the profit of different feedstocks. In the first graph on the second page, the profit for every ton of biomass is represented. Different feedstocks are compared here. The second graph represents the profit per Nm³ biogas produced.

Technical output:
It is advised to limit the grass use to 15-20 % in a wet digester. The fibers can cause problems for the pumps and mixing systems. Depending on the pre-treatment (for example extrusion) or digester type (for example a dry digester) the advised limit can be increased to up to 90 %.

Interpretation and conclusion:
This modelled tool is designed to evaluate different feedstocks relating to BGP and the digestate cost. It is suitable to compare different feedstocks against each other and against nature and roadside grass. This model does not take into consideration any processing or transport costs.

To find the tool, please follow this link:

The latest manuals „Good practice guide for grass valorisation“ are available now!

Recommendations for local authorities:
including municipalities, road and watercourse management authorities and (inter)municipal waste management organizations

Recommendations for biogas plant owners and operators:
Manual for operators of biogas plants and composting facilities with integrated biogas production

Recommendations for terrain managers:
including nature conservation organisations and stakeholders performing extensive management of permanent grasslands for nature conservation purposes or roadside verges

All the these manuals are (together with the Final Publishable Report and further informative documents) available on this link: