Britain’s energy sector has been hit by controversy after allegations from whistleblowers about the handling of the country’s electricity network during the late heatwave in June this year. The National Energy System Operator (Neso), a public corporation wholly owned by the UK government, has commissioned an independent legal review following claims that control room employees were instructed to avoid creating written records of decisions made to keep the grid stable during the period of exceptionally high temperatures.
The allegations, raised in Parliament by the Conservative Shadow Energy Minister Claire Coutinho, also accuse senior Neso executives of prioritizing the organization’s public image over energy security. According to the claims, management was prepared to increase the risk of power outages in order to avoid reputational damage.
Industry data shows that grid frequency briefly fell outside normal operating limits as a high-pressure heat dome reduced renewable electricity generation, caused unplanned outages at several gas-fired power stations and drove up demand as air-conditioning use increased.
This is not the first time this has happened. The UK came close to blackouts in January 2025.
The electricity network is under growing pressure as aging infrastructure, the retirement of fossil fuel power stations and the rapid rollout of renewable energy strain the system. The transition to a more renewables-based electricity system has proved difficult not only in Britain but across much of Europe.
UK National Grid data indicates that operating the system has become increasingly difficult as the share of intermittent wind and solar generation has risen. At the same time, the current challenges also reflect years of underinvestment in transmission infrastructure, delays to grid expansion and short-term policymaking rather than the energy transition alone.
According to Jonathan Kitson, senior policy adviser and energy policy lead at the Centre for a Better Britain, the problems stem largely from years of energy policy that prioritized intermittent wind and solar generation through generous subsidies.
“Intermittent electricity is much more difficult to balance and a lack of investment in dispatchable power such as gas and nuclear has left Britain increasingly dependent on imports with a less resilient grid. At times there is also more wind and solar generation than the system can absorb, forcing consumers to pay generators to switch off”, he said.
Spain's Grid Failure Exposes Structural Weakness
Although Britain has so far avoided a nationwide blackout, Spain and Portugal suffered a major grid failure on 28 April 2025 that left large parts of the Iberian Peninsula without electricity for hours. The Spanish government declared a state of emergency in several regions and deployed 30,000 police officers to help maintain public order.
Trains ground to a halt. Food spoiled in supermarket refrigerators as power failed. Cash briefly became king again after electronic payment systems went offline. Hospitals switched to diesel generators to keep critically ill patients alive. For the first time in decades, many cities were plunged into darkness at night, with residents relying on candles and seeing stars that are normally obscured by urban light pollution.
Within hours, hundreds of thousands of people were reminded how deeply life depends on something usually taken for granted in industrialized Western societies. Electricity runs through almost every aspect of daily life like a vital current, sustaining transport, communications, food supplies, hospitals and the financial system.
Again, the question was why and how it had come to this. Were renewables to blame? As the investigation progressed, however, it became clear that the outage had a more complex explanation.
First and foremost, the report released in October 2025 by the European Network of Transmission System Operators for Electricity (ENTSO-E) concluded that the blackout was triggered by a series of “cascading overvoltages”, increases in electrical supply voltage above the grid's normal operating range.
Interestingly, on the day of the outage, renewable sources accounted for 78% of Spanish electricity generation. While that unusually high share fueled speculation about the role of renewable energy, the ENTSO-E report did not identify renewable generation alone as the direct cause of the blackout. Nor was such a high share unusual for the Iberian Peninsula. Spain and Portugal frequently generate most of their electricity from renewable sources during periods of strong sunshine and favorable wind conditions.
However, the growing share of renewable energy may have indirectly influenced grid conditions. The shift toward more decentralized electricity generation changes the amount of reactive power absorbed by transmission lines and alters the direction of reactive power flows, making voltage regulation more complex.
Several countries, including Austria, Germany and Japan, have already introduced measures to improve reactive power management as their electricity systems become more decentralized. Because renewable generation is often more geographically distributed than conventional power plants, it may have contributed to a different reactive power profile on the Iberian grid.
This has fueled controversy over whether regulators underestimated the challenges of integrating large volumes of intermittent renewable energy into a grid that had not yet been fully modernized, particularly as conventional fossil fuel and nuclear power stations were being phased out.
Those concerns were echoed in a confidential International Energy Agency (IEA) report, which warned: “The high penetration of renewable generation without the necessary technical capabilities in place to keep them operating properly in the event of a disturbance […] can cause power generation outages, which could be severe”.
Nuclear Energy and Attacks on the German Power Grid
The underlying challenge posed by renewable energy generation and its interaction with aging grid infrastructure has become increasingly prominent as European governments have accelerated efforts to meet net-zero targets and reduce carbon emissions. Across Europe, governments have committed hundreds of billions of euros to the energy transition through renewable energy support schemes, electricity grid expansion and other decarbonization measures.
Nowhere is the tension between climate ambitions and energy security more apparent than in Germany. The country became Europe's flagship for the Energiewende, committing to phase out nuclear power while rapidly expanding wind and solar generation.
Germany also has among the highest household electricity prices in Europe, with taxes, network charges and renewable energy policies contributing significantly to consumer bills. In 2004, then Federal Environment Minister Jürgen Trittin famously claimed that promoting renewable energy would cost the average household only about €1 per month, “no more than the price of a scoop of ice cream”. The price of energy has since more than doubled.
When the country's final three nuclear reactors, Emsland, Isar 2 and Neckarwestheim 2, were shut down in April 2023, the lost generation was initially offset by a combination of increased coal and gas-fired electricity production, higher renewable output and increased electricity imports. At the same time, Europe was still grappling with the energy crisis triggered by Russia's invasion of Ukraine and the loss of Russian pipeline gas, which had sent natural gas and electricity prices soaring. Subsequent instability in the Middle East, including the conflict involving Iran, added further uncertainty to global energy markets. Together, these developments underscored the challenges of maintaining secure and affordable electricity supplies while pursuing rapid decarbonization.
At the same time, electricity demand is expected to rise significantly as transport, heating and industry become increasingly electrified. Meeting that demand will require not only additional generating capacity but also substantial investment in transmission infrastructure, energy storage and flexible backup generation. Germany's electricity grid remains among the most reliable in Europe.
The country’s regulator, the Bundesnetzagentur, has warned that maintaining that level of reliability will become increasingly challenging as conventional power stations are retired and a growing share of electricity comes from weather-dependent renewable sources. It has called for distribution grid operators to be given the power to control solar installations during critical grid situations, including by halting their feed-in.
Without sufficient investment in grid infrastructure, storage, dispatchable backup capacity and system flexibility, periods could emerge in which electricity supply becomes more constrained, increasing the risk of localized shortages and placing greater strain on the grid. That investment and the maintenance of the larger grid needed when dealing with intermittent sources like renewables all come at a cost, which is passed on to the consumer.
And lastly, there is an additional challenge in Germany, where climate activism has, in some cases, extended to attacks on energy infrastructure. In Berlin, more than 100,000 people were left without electricity after attacks on critical infrastructure in January 2026.
The Next Test for Europe's Power Grid
Europe's energy transition is clearly entering a new phase in which expanding renewable generation alone will no longer be enough. As electricity systems become increasingly dependent on weather-dependent sources, governments will need to invest far more heavily in transmission infrastructure, energy storage, voltage control, flexible backup generation and modern grid management.
At the same time, policymakers face difficult questions about the balance between intermittent renewable energy and dispatchable baseload generation from sources such as nuclear power and natural gas, particularly as electricity demand continues to rise through the electrification of transport, heating and industry.
Without addressing those structural challenges, the transition risks becoming increasingly dependent on subsidies, higher consumer electricity prices and costly interventions to maintain grid stability, while placing growing pressure on Europe's industrial competitiveness.
At the same time, Europe is pursuing ambitious emissions reductions while other major economies continue to expand fossil fuel use to meet rapidly growing energy demand. In 2024, China emitted an estimated 12.6 Gt of CO₂, India around 3 Gt and the European Union approximately 2.4 Gt, while China and India continued to expand coal-fired electricity generation. As a result, emissions growth elsewhere can outweigh reductions achieved in Europe. This is raising questions about how best to balance climate objectives with economic competitiveness and energy security.
Ultimately, the success of the energy transition is judged not only by the amount of carbon it eliminates but also by whether it can continue to deliver electricity that is reliable, affordable and secure without undermining economic growth and industrial competitiveness.