Europe’s renewables milestone reveals a hidden challenge

Europe has reached a defining moment in its clean energy transition. Wind and solar are now generating more electricity than fossil fuels, marking a major shift in the continent’s energy system. However, alongside this progress comes a growing challenge: how to integrate large volumes of variable renewable power into grids that were not originally designed for it.

A milestone with a catch

In 2025, wind and solar provided around 30 per cent of EU electricity, overtaking fossil fuels for the first time. Yet despite this achievement, Germany, France and the Netherlands still curtailed a record 3.9 terawatt-hours of renewable electricity because their networks could not absorb all available generation.

As the International Energy Agency highlights, maximising the benefits of high shares of wind and solar requires greater flexibility across generation, grids, storage and demand. Without this flexibility, renewable output is increasingly at risk of being wasted, slowing the pace of emissions reductions.

For operators, this is not just a technical issue but an economic one. Curtailment means lost revenue and underutilised assets, while periods of oversupply can lead to negative wholesale prices when generation exceeds demand. The result is a system where abundant clean energy does not always translate into usable energy.

Why curtailment persists despite record generation

The underlying challenge is the variable nature of wind and solar. Unlike conventional thermal generation, output is driven by weather conditions and can change rapidly, creating mismatches between supply, demand and available grid capacity.

At the same time, Europe’s electricity networks were largely designed around centralised, predictable power sources. As inverter-based generation becomes more dominant, the assumptions that underpin traditional grid operation, particularly around voltage stability, frequency control and fault response, are being tested. When system flexibility is limited, congestion builds and curtailment becomes unavoidable.

Engineering solutions to capture more value

Solving this challenge requires more than expanding transmission infrastructure. It also depends on a broader set of engineering solutions that help maintain stability across increasingly complex and inverter-dominated networks.

At equipment and system level, resistive technologies play a key role in supporting reliable operation. Dynamic braking resistors (DBRs) help protect wind turbines and power converters by safely dissipating excess energy during transient events such as sudden load changes or grid disturbances. Neutral earthing resistors (NERs) support safety and stability by controlling fault currents during earth faults. High-voltage filter resistors help maintain power quality by managing harmonics in networks with high levels of inverter penetration.

Load banks are also widely used to test, commission and validate the performance of generation and grid infrastructure under controlled conditions
As renewable penetration increases, fault behaviour and system response become more complex and less predictable. Ensuring that equipment performs reliably under both normal and fault conditions is becoming essential to maintaining grid stability and operational confidence.

Towards a more flexible, efficient power system

Europe’s transition past fossil fuels is a significant milestone, but it also highlights a critical truth: generation growth must be matched by integration capability. Without this, increasing volumes of renewable energy risk being curtailed or underutilised, reducing both economic value and system efficiency.

Expanding grid capacity, scaling energy storage and improving overall system flexibility will be essential. Alongside these developments, engineered solutions that support fault management, power quality and real-time system control will play a crucial role in unlocking the full value of renewable energy.

To learn how Cressall’s resistive technologies support grid stability, protection and renewable integration, speak to the Cressall team.