Traditionally biogas is converted into electricity and heat in a cogeneration installation. By doing so, 40% of the energy of the biogas is converted into electricity and 60% is available as waste heat. This waste heat is used for a small portion to maintain the temperature of the digester, the other part is available for other processes. Two classical bottlenecks of the traditional way of exploiting biogas plants are: the valorization of waste heat and the dependence on 1 customer for the purchase of green power certificates, cogeneration certificates and electricity.

When less than 30% of the waste heat can be used efficiently, it might be more interesting to convert biogas into biomethane, injecting it in the natural gas network and valorizing it elsewhere as energy source nearby the end user. This way, the end user can opt for ‘green gas’ the same way he can chose green power. If injection isn’t possible, there can be opted for biomethane used as transport fuel. Vehicles driving on natural gas can drive on biomethane without any conversion. A ‘wheel to wheel’ analysis demonstrates that biomethane is 50% more efficient than mineral energy sources.

A second bottleneck for current biogas plants is the dependency to 1 application for electricity. In many cases the green power, green power certificates and cogeneration certificates are sold to one big energy player. By developing the alternative application possibilities for biogas, the negotiation position for the producer is becoming more favourable.

In order to list the feasibility of these alternative application possibilities an analysis of the technological feasibility of reprocessing and storage (quality requirements of gas, safety, waste management, etc.) will be made. Furthermore, it will be verified how the storage and supply of the biomethane to the gas consumer can best be organized technically (safety aspects, required pressure, consumer profile, legal requirements/restrictions concerning the injection in the natural gas network, etc.).

More specifically, the technical and economical feasibility of a biogas reprocessing installation connected to a digestion installation is studied on the Greenbridge science park.