BIOMASSE KRAFTWERK GÜSSING GmbH & Co KG

Dwindling reserves of fossil energy carriers, and the growing awareness of the problem of the greenhouse effect, have awakened increased interest in electricity from biomass in recent years.
The Kyoto treaty and the EU White Book (“Energy for the future: Renewable energy carriers”) represent important milestones here. Electricity from biomass is carbon-neutral and replaces dependence on energy imports by local net production.
Sustainable energy management is not just a slogan for the town of Güssing in the south Burgenland region, but has been a reality for years.
Güssing is the European Centre for Renewable Energy. One of the largest biomass district heating networks and an RME plant for the production of biodiesel have also been set up, and underline the importance of this form of energy for Güssing.

New type of power plant

In order to enable the production of electricity from biomass in small, decentralised power plants too, a new type of power plant was realised for the first time in Güssing. It uses a gasification process which offers advantages over combustion processes, particularly when used for combined heat and power.
In the Güssing biomass power plant, every hour 1,760 kg of wood produces 2,000 kWh electricity and 4,500 kWh district heating.
To realise this project, from idea through to finished product, the partners REPOTEC as plant engineers, scientists from Vienna Technical University, EVN and the Güssinger Fernwärme district heating company joined forces to form the expert network RENET, and developed this new, economically and technically sophisticated system of combined heat and power based on biomass gasification.

RESEARCH & DEVELOPMENT

•    REPOTEC Umwelttechnik GmbH
•    VIENNA TECHNICAL UNIVERSITY
•    FERNWÄRME GÜSSING [district heating company]
•    REPOTEC
•    GE-JENBACHER ENERGY
•    BEGAS
•    EVN

 

THE METHOD

Steam gasification
The heart of the plant, the fluidised bed steam gasifier, comprises two fluidised bed systems that are connected to one another. In the gasification part, the biomass is gasified at approx. 850 °C, with steam being supplied. By using water vapour instead of air as the gasification medium, one produces a nitrogen-free, low-tar product gas with a high calorific value. Some of the remaining coke is transported via the circulating bed material (sand), which acts as a heat carrier, into the combustion section for combustion. The heat that is thereby diverted to the bed material is needed to maintain the gasification reactions. The flue gas is extracted separately, with the heat that it contains being used to stream off district heat.

Gas cooling and gas purification
For the function of the downstream gas motor, the product gas has to be cooled and purified. Naturally, the heat that is given off during cooling is, once again, used for producing district heating. After that, the gas is de-dusted in a fibrous filter. The wet scrubber that is installed after that reduces the concentrations of tar, ammonia and acid gas constituents. Through the special process, it is possible to feed all residual substances left over from the process back in, so that no waste material or waste water is produced during gas purification.

Gas motor
The gas motor converts the chemical energy of the product gas into electrical energy. Furthermore, the waste heat from the motor is likewise used to produce district heating. Through this, it is possible to achieve levels of efficiency that were previously unachievable in biomass utilisation. Electrical efficiency is around 25–28 %, and the overall level of efficiency (electricity and heat) is even over 85 %.

Further technical details can be found at www.renet.at and www.repotec.at.