TenneT Prepares Dutch Grid for 1.3 GW Solar Generation Drop During August Eclipse

Dutch transmission system operator TenneT is preparing for a temporary reduction in solar power generation during the 12 August 2026 solar eclipse, with the event expected to reduce photovoltaic output in the Netherlands by approximately 1.3 GW.

The grid operator stated that the near-total eclipse will require close monitoring and coordination to maintain the balance between electricity supply and demand.

The eclipse is expected to cover almost 90% of the sun above the Netherlands, taking place between approximately 19:10 and 21:03 local time on August 12. However, TenneT expects the impact on the electricity system to remain manageable because solar generation is already declining significantly during the evening hours as the sun approaches sunset.

According to TenneT, the anticipated 1.3 GW reduction in solar generation is equivalent to the electricity consumption of more than one million households, highlighting the scale of the temporary impact on the power system.

The Netherlands currently has approximately 30 GW of installed peak solar PV capacity, making solar forecasting and grid flexibility increasingly important for maintaining system reliability as renewable penetration continues to grow.

TenneT has been preparing for the eclipse for around nine months, using weather forecasts, solar generation data and insights from the previous solar eclipse in March 2025 to model potential impacts and develop operational strategies.

During the eclipse, TenneT will coordinate closely with electricity market participants, including TTEP Netherlands, which provides balancing and emergency capacity, as well as other European transmission system operators to ensure sufficient flexibility and maintain grid stability.

The event is also expected to affect other European electricity markets. Spain’s transmission system operator Red Eléctrica de España (REE) forecasts that solar generation could decline by approximately 5 GW during the eclipse, particularly in areas where the eclipse reaches totality. Similar to the Netherlands, the impact will be influenced by the timing of the event, which coincides with lower solar production periods in the evening.

The upcoming eclipse demonstrates the operational challenges faced by increasingly renewable-based electricity systems. As solar capacity expands across Europe, grid operators are placing greater emphasis on accurate forecasting, flexible generation resources, cross-border coordination and energy storage solutions to manage short-term fluctuations in renewable output.

For grid operators such as TenneT, events like solar eclipses provide valuable opportunities to test renewable integration strategies and strengthen the resilience of future low-carbon electricity networks.