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Photovoltaic (PV) battery systems allow citizens to take part in a more sustainable energy system. Using the electric energy produced on-site usually entails a financial benefit for the consumer. Furthermore, feed-in peaks during high photovoltaic generation sometimes cause local voltage violations. Therefore, a feed-in limit applies to PV battery systems. In our study, we present a method to generate an optimal control that takes into account the forecast uncertainties. To that end, a stochastic forecast model is developed and used in a dynamic programming framework. We carry out a simulation study assuming the regulatory constraints in Germany. In this setup, our method is shown to mitigate the effects of the forecast uncertainties better than comparable methods. [ABSTRACT FROM AUTHOR]

Abstract Fast frequency response services become more relevant in power systems with a high share of fluctuating renewable energy sources and decreasing shares of conventional generators. In Germany there are special requirements for providers of Primary Control Reserve (PCR) with limited storage capacity. Furthermore, regulatory degrees of freedom are available for these to control their state of charge (SoC) within allowed limits. In Great Britain, the Enhanced Frequency Response (EFR) service was developed considering storage limitations and thus introduces the concept of envelopes to support SoC maintenance. In this paper, the concept of EFR envelopes is adapted to the provision of PCR in Germany. It is shown that the dynamic use of envelopes effectively maintains SoC away from extreme values and close to 50 % for most part of the year, reducing cycling and significantly decreasing the need for corrective measures from external sources to maintain the battery's SoC. [ABSTRACT FROM AUTHOR]

Battery energy storage systems have a large potential for provision of grid ancilliary services. Specifically, large battery systems have been used for the provision of primary control reserve. Batteries providing this grid service must, using corrective energy measures and control algorithms, continuously keep their state of charge within limits in order to comply with European regulations. Operational degrees of freedom exist in the regulation which can be used by batteries to facilitate keeping the state of charge within desired levels. In this paper, such degrees of freedom are described, and the effect of their utilization on battery system operation analyzed. [ABSTRACT FROM AUTHOR]