News : German scientists obtain car-fuel from biological waste

Research in Germany: Biowaste such as kitchen refuse can be converted into biogas fuel

German scientists obtain car-fuel from biological waste

January 28, 2010

Scientists at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB and several research partners from the energy sector are working together in the research project ETAMAX to produce biogas from waste such as supermarket waste and micro-algal biomass. The regenerative bio methane will then be used to fuel a small fleet of gas-driven vehicles.

Due to its high net energy yield, biogas, essentially a by-product of fermentation containing methane and carbon dioxide is a very important renewable energy carrier. The Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart hopes to harness this resource as an alternative to fossil fuels for use in transportation. IGB is working closely with partners from research, the energy sector, and the car and plant engineering industries.

The objective is to fully exploit easily fermentable, inexpensive bio waste and algal biomass for maximum energy recovery. Professor Walter Trösch, deputy director and head of the Department of Environmental Biotechnology and Bioprocess Engineering of the Fraunhofer IGB says that "Bio methane can be transported along the existing network just like natural gas and it can also be used to drive CNG vehicles (compressed natural gas), which is something we are doing as part of our pilot project.

Recycling of waste biomass

The researchers are mainly focusing on recycling wet waste biomass that can be easily and quickly fermented and that does not compete with food production: waste from the food industry which contains a high proportion of water, for example. In addition, kitchen waste from private households, canteen kitchens and student restaurants or supermarket waste which usually ends up in composting facilities, and whose energy is lost as heat.

Additional biomass through algae culture

Other than waste biomass, Fraunhofer IGB also intends to algal fermentation. The production of energy from algal biomass has become a very efficient process thanks to a photo bioreactor platform developed at the Fraunhofer IGB.

Bio methane as regenerative fuel

These processes are being carried out and tested on the technical scale in a pilot plant on the premises of the EnBW co-generation power station in Stuttgart Gaisburg. It is envisaged that a future large-scale plant will be able to produce 300,000 cubic metres of methane gas per year from the municipal bio waste produced in the city of Stuttgart.

After purification, the methane produced can then be used to fuel a small fleet of refuse collection vehicles with natural gas engines. The use of methane will also have benefits for air quality. In addition to closing the carbon cycle, the optimisation of biogas fuel quality will be further advanced in collaboration with EnBW Energie Baden-Württemberg AG and the use of methane as car fuel will be further advanced in collaboration with Daimler AG.

ETAMAX

The project, which started in June 2009, will be funded for a period of five years with a total of 6 million Euros from the German Ministry of Education and Research (BMBF) as part of the "BioEnergie 2021" programme.