Up until recently, the operators of biogas plants were only concerned with producing and supplying as much electricity into the grid as possible. Now it can pay to produce electricity when demand is highest.



Biogas plants are capable of making a big contribution to offsetting natural fluctuations in the fast-growing segment of electricity generation from wind and solar power. That most of them are still not equipped for this, however, became apparent in April at the symposium “Demand-oriented Electricity Production from Biogas and Biomethane” hosted in Berlin by the Association of German Engineers (VDI). It used to be that the main concern was producing and supplying as much electricity into the grid as possible, said Alfred Gayer, executive director of the biogas marketer Envitec Energy. Today it’s important to synchronize production with target-market demand.

Nowadays there are incentives for plant operators to produce biogas electricity in times of electricity shortages and not during electricity surpluses. A condition for this is that they no longer sell their electricity to grid operators like they used to, but to specialized green-electricity marketers. Higher earnings are possible thanks to management and flexibility premiums as well as to additional revenues from the sale of peak-load electricity in line with market requirements. Thus, according to Michael Tiedemann, sales manager of biogas plant constructor MT-Energie, the operator of a standard plant could make more profit over a period of ten years despite additional investments than he could with a plant in continuous usage.

And yet biogas operators have only seemed to embrace the basic model of direct marketing and management premiums. The flexibility premium, on the other hand, is not much in demand. To date only 190 out of 7,500 biogas plants in Germany have applied for them, concluded Uwe Holzhammer, group manager at the Fraunhofer Institute for Wind Energy and Energy System Technology (IWES). The reasons for this include legal uncertainties and the required investment in additional plant technology. In order to operate flexibly, a biogas plant needs new communications technology, greater crude-gas storage tanks and higher capacity at combined heat and power stations. An alternative to power-plant expansion is adding on a small processing plant for biomethane.

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