Project description

"Improving the energy efficiency of composting and co-fermentation"

Co-financed by: Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU)

Project duration: 07/2009 - 06/2012

Project coordinator BUW: Prof. Dr.-Ing. Eckhard Kraft

Technische Universität Braunschweig (TUBS) (improving energy efficiency of biogas production),
ATZ Entwicklungszentrum (improving energy efficiency of combustion)

The effective use of organic residues can make an important contribution to conserving resources and to climate protection. In Germany 110 Mio Mg dry organic residues are produced annually. The utilisation of these materials - might they be for energy recovery, material products, or a combination of both - should be done as energy efficient as possible. The goal of this sub-project was the identification of energy efficiency potentials for composting plants and for co-digestion at wastewater treatment plants in order to allow them to increase their energy efficiency.

Based on data from literature a questionnaire for each technology was created to gather more relevant data. Although the planned analysis of the energy consumption of single plant components was impeded by the lack of respective data, it was possible to identify some major efficiency potentials. The influences of boundary conditions on the energy consumption were also regarded.

One resulting main message is the dependancy of the energy efficiency of composting plants, i.e. the energy consumption per amount of input material, from the type and amount of the input material as well as from the intended output. Therefore, it is not recommended to devise measures for energy efficiency based on the comparison of composting plants which apply different components or which operate in different settings. For each plant specific measures should be developed. To support plant operators in such efforts the SWOT analysis - mainly applied in business administration - was adjusted specifically for composting plants and for co-digestion units on wastewater treatment plants, with focus on energy efficiency. With the provided data from this project and data gathered from a specific plant, operators should now be able to utilise the SWOT to identify energy efficiency potentials and to develop specified measures to exploit them.

Last update: 22.11.2013