Fully flexible biogas plant

Demand-driven electricity and heat production

The renewable energy sector is constantly developing and progressing. Feeding green energy into the power grid presents challenges, however, due to the fluctuating nature of production. One means of solving this problem is to operate biogas plants in a flexible way, since this makes it possible to control the time when electricity and heat are produced. The example of the fully flexible biogas plant run by Bioenergie Guntrup GmbH shows how this innovative technology works in practice and how it can be integrated into an existing system in a way that is both environmentally and economically sound.

Since 2011, the Münsterland-based company for constructing and operating biogas facilities has been operating its own biogas plant in Greven with a 370-kilowatt combined heat and power (CHP) unit and a 190-kilowatt satellite CHP unit. The company decided to further develop the plant with the support of the engineering company Energethik Ingenieursgesellschaft in order to make it more efficient and fit for the future. A new installation of approx. 1,200 kilowatts significantly increased capacity, and an important step towards making the system more flexible was taken with the integration of a gas storage facility. The CHP unit no longer operates continuously but responds to the requirements of the electricity market. The biogas produced can be stored at the facility for extended periods of time. This takes the burden off the grid run by the Greven public utility company, which the biogas plant supplies.

Engine for progress:

  • Full flexibilisation of an existing biogas plant
  • Flexibilisation combined with utilisation of heat
  • Increase in electrical and thermal efficiency
  • Lower transmission losses through the use of a ten-kilovolt generator

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Photo: Energethik Ingenieurgesellschaft mbH

New transmission station and transformer at the biogas plant in Guntrup.

Increased efficiency through flexibilisation

The CHP unit was equipped with a new, more powerful FLEX motor, which provides a significantly better level of electrical efficiency. Not only is it more efficient to operate, but a higher electrical and thermal output is also achieved for the same amount of substrate. The installation of a ten-kilovolt generator also increases efficiency. This runs on mains voltage, meaning that conversion via a transformer is not required and the losses caused by this process are avoided. As well as better utilisation of the plant, the company also benefits from the fact that the motor has a longer service life and lower maintenance and repair costs are involved.

Innovative use of heat

The heat produced in the CHP unit is also used to supply the surrounding buildings and a greenhouse via a district heating network. In this instance too, heat accumulators make it possible to supply heat according to demand, which is particularly significant in the winter months. Since less heat is needed in summer than in winter, less substrate is used and less biogas is produced. When the need for heat increases in the winter, more substrate is used and more biogas is produced. Particularly with regard to the greenhouse, the substrate variation is very important, if, for example, the sun and wind do not supply enough energy, the flexible biogas plant can balance the deficit.

As a result of their more efficient operation and flexible way of working at different times of the year, fully flexible biogas plants achieve a significant climate change mitigation effect. As controllable sources of renewable energy and the foundation stone for integrating further types of green technology, they are an important facet of the energy transition and a climate-friendly alternative to power plants fired by fossil fuels.

Photo: Energethik Ingenieurgesellschaft mbH

"By producing electricity based on demand, the Guntrup bioenergy plant reduces the need for the residual load to be covered by coal- and gas-fired power plants. At the same time, the plant utilises all the accrued heat by means of a heat accumulator, thereby replacing fossil fuels. It is a prime example of a modern, future-oriented biogas plant."

Robert Wasser, Executive Partner, Energethik Ingenieurgesellschaft mbH

Partners and sponsors

  • Bioenergie Gruntrup GmbH & Co. KG
  • Energethik Ingenieurgesellschaft mbH