Context
Non-firm grid connections represent a promising solution to facilitate faster and less costly connection of photovoltaic production to the electricity distribution network, particularly at low voltage, and especially in rural areas where electrical conductors are longer and have smaller cross-sections than in urban areas. Despite their potential, and despite the French Decree of July 12, 2021, which introduced them into the Energy Code, non-firm connections remain marginal in France on the medium voltage network and are completely unutilized in the low voltage network. In this context, the Drôme Energy Syndicate wished to conduct an experiment on the network of the Érôme-Gervans municipal utility to evaluate the relevance of a smart connection for a 6.6 kVA photovoltaic producer fed by an LV feeder subject to frequent high voltage excursions during periods of high solar production.
Problem Statement
The project’s main objectives were operational: to concretely implement a non-firm connection on a low-voltage feeder supplying an existing photovoltaic installation to gain feedback and useful recommendations for potential future industrialization of this type of solution. Given the diversity of possible approaches to implement a smart connection—ranging from local regulations integrated into the inverter’s firmware to centralized solutions relying on a complete communication chain—the project also aimed to compare these different modes of flexibility implementation.
Achievements
- Experimentation with a non-firm, low-voltage generation connection, based on the Grid ExpanDER software platform developed by Roseau Technologies.
- Validation of the technical feasibility of non-firm connections and compilation of a technical report proposing various recommendations related to their industrialization.
- Analysis, on a concrete case, of the technical benefits (gain in hosting capacity) and economic benefits (avoided investments) related to an alternative connection solution, according to two complementary methodologies: a numerical simulation approach, based on Roseau Load Flow and Berenis software for modeling and analysis; and an experimental approach, based on direct measurement of curtailed energy and observed hosting capacity gain in the field.
Impact
The project successfully demonstrated, in a concrete case, the feasibility and the technical and economic benefits of a flexible connection, confirming the interest of this approach in a rural context where hosting capacities are often limited. Beyond this targeted demonstration, the project also led to the development of practical recommendations to promote the generalization of non-firm grid connections, both technically and methodologically.
