Assessing maximum grid loadability under PV deployment for distribution planning support: a Swiss case study

The increasing integration of low-carbon technologies, such as solar photovoltaics (PV) and heat pumps, impacts the operational margins of distribution grids. This paper quantifies the margins to voltage violation and line overloading by calculating the maximum grid loadability (MGL). We quantify this metric for 873 inferred Swiss medium-voltage grids and investigate the effect of rooftop PV and heat pump deployment by 2040. Results show a median MGL increase of 4.8% due to PV in summer and a median decrease of 11.1% due to heat pumps in winter. Overall, MGL is projected to increase by 14.0% until 2040, primarily driven by efficiency measures decreasing conventional loads. We highlight grid diversity, flexibility, energy efficiency, and winter peak as distribution planning considerations influencing operational margins.