Balancing of fluctuating renewable power sources


Ukraine plans to substantially increase the share of renewable energy sources (RES) in its power mix. This prospect has stimulated an important debate on the technical capacity of Ukraine’s power system to accommodate growing shares of fluctuating generation from wind and PV-solar. In this context, one crucial question is whether the current power plant park is able to balance the fluctuations from wind and solar generation.

Based on a dispatch optimisation model approach1, we assess that the current Ukrainian power system can balance fluctuations of up to 15 GW of wind and solar. This assessment is based on the observed flexibility of the Ukrainian power plant fleet (nuclear, thermal, big hydro, pump hydro and cogeneration). Only with very high shares of renewables (15 GW), some excess generation from renewables must be curtailed. But even then, curtailment losses remain limited to about 10%.

In the short term, the existing power plant park should be sufficient to balance fluctuations from renewables. However, the aging stock of conventional power capacities as well as a potential increase of power demand will create pressure for action in the medium and long term. Furthermore, an integration of RES above 15 GW as part of a decarbonisation strategy will require the development of a power system that is much more flexible than the current one. Investment into power capacities, grids and substations need to take the long-term perspective into consideration.

Different technological and non-technological options for balancing fluctuating renewable generation – such as storage, the variable use of biogas, a market for balancing energy, increased cross-border integration and demand response – have to be considered in the development of the future power system.

Dr. Georg Zachmann, Dr. Frank Meißner

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