Enexis is expanding a rooftop solar dimming initiative beyond its pilot phase, opening the voluntary scheme to around 55,000 new households
The program is aimed at helping manage grid constraints during periods of high solar generation
The rollout comes as Dutch grid operators face increasing congestion challenges across their networks
Dutch grid operator Enexis is expanding its Zonnedimmer (Solar Dimmer), a voluntary rooftop solar energy curtailment program, to around 55,000 new households to relieve congestion on the power grid during peak times.
The voluntary scheme allows participating households to agree to temporarily reduce their solar power exports to the grid when network capacity comes under pressure.
Enexis says the expansion will target households in parts of Groningen, Overijssel, North Brabant, and Limburg, where rising numbers of rooftop solar installations are straining local electricity networks during midday peaks in solar generation. This creates challenges for grid operators as available network capacity becomes increasingly constrained during sunny periods.
The wider rollout follows pilot projects in Helmond and Waalwijk, shared the grid operator.
Through Zonnedimmer, Enexis can temporarily reduce the output of participating rooftop solar systems during periods of expected local grid congestion. The measure is designed to address a growing issue on sunny days, particularly between 11 a.m. and 3 p.m., when solar generation peaks while electricity demand remains relatively low.
During these hours, large amounts of power are exported from residential solar systems, which can strain local distribution networks and create bottlenecks in areas with high solar penetration.
Enexis said it already uses congestion management measures involving large-scale renewable energy projects, including agreements with solar and wind farms to reduce electricity exports during peak periods.
However, the company noted that rooftop solar systems now account for a significant share of generation in several regions. This makes residential flexibility an increasingly important tool for grid management.
Under the program, participating households will receive compensation and will be able to monitor curtailment events through a dedicated app. Enexis said solar output will only be reduced when necessary and only in postal code areas facing network constraints.
The expansion of Zonnedimmer highlights a broader shift in how European grid operators are managing renewable energy growth. While network reinforcement remains the long-term solution, operators are deploying flexibility measures to maintain reliability as solar deployment outpaces grid expansion.
Enexis’s move comes amid growing congestion concerns across the Netherlands. Another Dutch grid operator, Liander, has reported that thousands of households and businesses are facing delays in obtaining new or upgraded electricity connections because of limited grid capacity. In some areas, waiting time can run up to 3 years, according to the company.
Liander then recommends that consumers help reduce grid congestion by running their electric appliances at noon and charging their electric vehicles (EVs) at night to improve grid utilization.
Nonetheless, the Dutch Authority for Consumers and Markets (ACM) is set to make it mandatory for grid operators to prioritize capacity on the electricity grid. From July 1, 2026, grid operators will prioritize essential services such as healthcare, safety, and education first, while households will have to wait longer for new grid connections and capacity requests. Businesses with a small-scale connection may face longer waiting times than the residential segment since they are not prioritized under the new ACM rules.
The rules aim to ensure fairer allocation of scarce grid capacity but do not address the underlying capacity shortage, admits Liander. Dutch solar association Holland Solar, on the other hand, recommends promoting decentralized energy systems with the use of batteries and smart software, along with solar, to reduce strain on the grid.
ACM is also planning to bring in a feed-in tariff for large electricity producers, including solar and wind farms, by January 1, 2032. Under this, power generators will have to share grid costs, a move that does not find favor with the renewable energy industry groups (see Dutch Feed-In Tariff Plan Sparks Industry Concerns).