The importance of battery storage systems in reducing grid issues in sector-coupled and renewable low-voltage grids

Transforming the energy system towards renewable energies and the electrification of the transport and heating sectors is necessary. A substantial part of this transformation occurs in the low-voltage grids. The increasing number of photovoltaic systems, electric vehicles and heat pumps poses new challenges for low-voltage grids. The load on lines and transformers is increasing due to higher electricity demand. Battery storage systems and the flexible operation of consumers can increase photovoltaic self-consumption and relieve low-voltage grids by using a grid-serving mode of operation and thus supplement grid expansion.We conducted time series-based load flow calculations using five representative low-voltage grids for four weeks of the year. We determined the loads and the need for curtailment caused by a high expansion of roof-mounted photovoltaic systems and new sector-coupled consumers and how these loads and curtailment can be reduced with the help of battery storage systems and flexible consumers.Our analyses show that consumption-related overloads can be completely avoided, and the share of locally consumed photovoltaic energy can be doubled. Digitalising the low-voltage grids is required to detect overloads and allow battery storage systems and consumers to react specifically to these grid overloads. Rural low-voltage grids are particularly affected by overloads, as they have greater rooftop photovoltaic potential and tend to be weaker. Battery storage systems and smart consumers are thus becoming essential cornerstones for the transformation of the energy system.