Biogas plants and battery storage for more flexibility
Why battery storage as a green co-location is the future of flexibilization of biogas plants
EEG (Renewable Energy Sources Act) funding has been a key driver of the expansion of renewable energies in Germany, particularly for biogas plant operators. However, a critical date is approaching for many pioneers in the biogas sector: the end of the 20-year EEG subsidy or the subsequent follow-up subsidy. Without the fixed feed-in tariffs, many biogas plant operators are faced with the question of how they can continue. Coupling biogas plants with battery storage systems offers an innovative option.
The end of EEG subsidies
The operation of a biogas plant used to be more predictable: produce and feed in, no matter what time of day. However, with the end of subsidies, biogas plants have become market participants. Those who feed in electricity when the sun is shining and the wind is blowing often only receive minimal or even negative prices. Flexibilization is vital to remain economically viable.
Co-location battery storage as an alternative remuneration model
A battery storage system can offer a way of increasing flexibility so that electricity production can be detached from the time of sale. There are two main concepts that differ in legal and technical terms:
Green co-location: focus on biogas power
In the case of green co-location, the battery storage system is fed exclusively from the biogas plant (and possibly other renewable sources on site). The battery storage system enables cross-market optimization, i.e. marketing in different electricity markets. The battery can thus offer electricity on the spot market, in balancing energy or in intraday trading.
Gray co-location: Maximum market freedom
The gray co-location eliminates the strict separation between green and gray electricity. Here, the battery storage system can draw electricity from the biogas plant as well as from the public grid.
What do I need to consider with battery storage for my biogas plant?
A common mistake in planning is to size the battery storage system too small. As a rule, the battery should be larger than the output of the biogas plant (CHP). Why? Only if the storage capacity can absorb the entire generation volume of the CHP plant over several hours can production be completely shifted to the most attractive time windows of the day on the intraday market.
If the storage tank is too small, the biogas plant operator is forced to feed in even at times of low prices as soon as the battery storage tank is full. The full flexibility and thus the maximum profit cannot be fully utilized.
Conclusion: Battery storage as an opportunity for biogas
The combination of biogas and battery is an innovative way of enabling the biogas plant to continue operating in an economically viable and profitable manner, independent of fixed feed-in tariffs.
Would you like to know what storage size would be ideal for your specific CHP output? Or whether it is worth marketing your flexible biogas plant? Feel free to make an appointment with our colleague Matthias Mengler:
