"Biogas has to move from pure flat feed-in towards flexibility, in order to be future-proof and to advance the energy revolution!” Fortunately, this sentence is now often heard in Berlin's energy policy circles, in industry associations and sometimes even on television. But Gerd Clasen from KBB Biogas GmbH & Co KG is not sitting in Berlin and not in front of a camera when he says this sentence. Gerd Clasen sits in the control room of a biogas plant in Kirchlinteln, in Lower Saxony. He can implement what the others are talking about.
Biogas plants have everything that a flexible power plant needs: often stepless controlable motors, constant gas supply and their own gas storage. The German Renewable Energy Sources Act (EEG) 2012 added the legal amendment in order to exploit this flexibility on the energy markets. Those who switch to direct marketing according to the so-called market premium model can offer the flexibility of their own biogas plant both on the EEX spot market and on the balancing energy markets. Gerd Clasen was immediately convinced by the new concept: "After one or two months, I understood that direct marketing on the spot exchange is the right way to go and that sooner or later all operators will change.” Together with the four other local partners, he decided to bring KBB's biogas plant to the electricity markets as part of Next Kraftwerke's virtual power plant.
Gerd Clasen recalls that the start into direct marketing went off without a hitch: “We had the contract with Next Kraftwerke reviewed by a lawyer, received the re-registration from the grid operator of Next Kraftwerke and then the direct marketing started quickly. The marketing of our biogas electricity on the stock exchange is very transparent, we can calculate monthly on the basis of the invoices from Next Kraftwerke what additional revenues we have received through the market premium model compared to the old model, the fixed EEG feed-in tariff.".
But what about the supreme discipline, the marketing of plant flexibility on the balancing energy markets? Here, in contrast to pure direct marketing, the virtual power plant intervenes in the plant operation mode and regulates the biogas plant according to the specifications of the transmission grid operators in order to support the electricity grid. After the installation of the remote control unit, a so-called Next Box, by the local maintenance company of the biogas plant, it was networked with the headquarters of the virtual power plant in Cologne. Subsequently, various tests were carried out to prove the plant's controllability with the transmission grid operators ("pre-qualification"), so that KBB's biogas plant received notification of the marketing launch of the balancing energy as early as mid-2013.
Gerd Clasen remembers the first call with a smile: "I sat with coffee and cake and received an SMS that there was a secondary reserve call. Then I could watch live at my plant control how the CHP was down-regulated within seconds from Cologne. After the end of the call the CHP drove up again fully automatically. My coffee hadn't even got cold." Since then, the two CHPs of the KBB biogas plant have repeatedly provided balancing energy for grid frequency stabilisation, both tertiary reserve and secondary reserve. The CHP units receive a signal via the Next Box to adjust the output - in the case of the larger of the two CHP units, for example, from the maximum output of 600 kW down to 360 kW. "When the contract was signed, we were able to decide for ourselves how far the CHP unit could be reduced. So far, every call-off has gone smoothly," explains Gerd Clasen. The remuneration for the balancing energy provided is made up of two components, on the one hand a stand-by fee ("performance price") and on the other hand the call-off remuneration, which is contractually guaranteed to be above the lost electricity remuneration for the duration of the call-off ("working price").
The KBB is certain that the path it has chosen is sustainable. So much that the operating company already considers the requirements of the tertiary and secondary reserve, in the technical and financial planning of the next CHP plant extension. Also taken into account, the demand-oriented feed-in at peak load times on the electricity exchange with the help of the flexibility premium (the flexibility premium is regulated in the EEG and additionally remunerates flexible renewable energy systems). "Then we will be even more flexible", Gerd Clasen is already looking forward to.
Facts & Figures
|On-site CHP units 1-5||600 kW, 366 kW, 190 kW, 265 kW, 265 kW|
|Satellite CHP units 1 & 2||265 kW, 265 kW|
|Gas storage capacity||12.430 m³|
|Fermenter volume||8.601 m³|
|Applied product:||Direct marketing and balancing energy for biogas plants|