Assessing strategies to manage distributed photovoltaics in Swiss low-voltage networks: An analysis of curtailment, export tariffs, and resource sharing

TL;DR

This paper evaluates different strategies like tariffs and curtailment to manage distributed photovoltaics in Swiss low-voltage networks, aiming to balance PV deployment with grid stability and reliability.

Contribution

It provides a comparative analysis of capacity-based tariffs, export tariffs, and curtailment policies, highlighting their effects on PV integration and grid constraints in Swiss low-voltage networks.

Findings

Capacity-based export tariffs severely penalize PV deployment.

Curtailment at 50% and 70% enables high PV integration.

Mixed tariffs with curtailment mitigate grid impacts effectively.

Abstract

The integration of photovoltaic systems poses several challenges for the distribution grid, mainly due to the infrastructure not being designed to handle the upstream flow and being dimensioned for consumption only, potentially leading to reliability and stability issues. This study investigates the use of capacity-based tariffs, export tariffs, and curtailment policies to reduce negative grid impacts without hampering PV deployment. We analyze the effect of such export tariffs on three typical Swiss low-voltage networks (rural, semi-urban, and urban), using power flow analysis to evaluate the power exchanges at the transformer station, as well as line overloading and voltage violations. Finally, a simple case of mutualization of resources is analyzed to assess its potential contribution to relieving network constraints and the economic costs of managing LV networks. We found that the tariff with capacity-based components on the export (CT export daily) severely penalizes PV penetration. This applies to other tariffs as well (e.g. IRR monthly, Curtailment 30, and DT variable) but to a lesser extent. However, the inclusion of curtailment at 50\% and 70\%, as well as mixed tariffs with capacity-based components at import and curtailment, allow for a high degree of PV installations in the three zones studied and help to mitigate the impact of PV on the distributed network.