Heat wave test for the grid

The recent heatwave has placed unprecedented stress on Greece's electricity grid, exposing the challenges of transitioning to renewable energy while maintaining reliable supply. As temperatures soared and demand for electricity surged due to widespread use of air conditioning, the national grid faced its most rigorous test yet. The situation revealed the limitations of current infrastructure and highlighted the ongoing reliance on traditional fossil fuel-based generation to meet peak loads.

From June 24 onwards, all available natural gas units were activated, alongside the lignite-fired Ptolemaida 5 plant operated by Public Power Corporation (PPC). This plant, particularly active during evening hours, played a crucial role in balancing the grid. However, the exception came on Sunday, June 28, when strong winds significantly increased the contribution of renewable energy sources—renewables accounted for over 67% of the energy mix. This fluctuation underscored the volatility of renewable energy and the necessity of backup generation to ensure stability.

The Greek energy system, though increasingly reliant on renewables, remains vulnerable during periods of high demand and low renewable output. During daylight hours, solar power contributes substantially, but as the sun sets, this source disappears entirely, leaving wind energy to take over. When wind conditions are favorable, the need for costly thermal power stations decreases. Conversely, when wind dies down, the burden shifts back onto natural gas and coal, highlighting the cyclical nature of energy supply in the country.

Recent experiences in other parts of Europe, such as the severe heatwaves in Western Europe, have shown how critical reserve capacity is in maintaining grid reliability. These events forced operators to rely on emergency measures, including the activation of older and more polluting power plants. In Greece, despite the grid operating near full capacity, the National Power Transmission Company (ADMIE) remains cautiously optimistic. They estimate that even if demand peaks at 10,000 MW, the system will not face a shortage of power. This confidence stems from the availability of multiple generation technologies and the ability to quickly respond to fluctuations in demand.

Natural gas units are expected to remain operational throughout the summer, with only one unit currently out of service due to mechanical failure. The Ptolemaida 5 plant is anticipated to play a vital role during the summer months, and ADMIE has already instructed PPC and the Ministry of Energy to ensure its continued operation until March 2027. This extended commitment reflects the strategic importance of the plant in maintaining grid security during periods of high demand.

Another factor contributing to the system's resilience is the increased water levels in hydroelectric reservoirs managed by PPC. These reserves have risen by approximately 20–25% compared to previous years, providing additional flexibility in managing load distribution. Furthermore, exports of electricity have increased, offering a buffer that can be redirected to domestic consumption if necessary. These measures collectively enhance the system's ability to handle surges in demand without compromising reliability.

Despite these safeguards, certain areas remain more exposed than others. Remote islands, disconnected from the mainland grid, experience heightened vulnerability during the summer months due to the surge in tourist activity. The increased demand for electricity on these islands often strains local resources, making them more susceptible to potential disruptions. To address this, the Hellenic Electricity Distribution Network Operator (ΔΕΔΔΗΕ) has proposed a new plan to the Regulatory Authority for Energy, Networks, and Environment (ΡΑΑΕΥ), aiming to improve energy management and reduce risks associated with isolated grids.

In addition to traditional generation methods, Greece is beginning to leverage emerging technologies to bolster grid resilience. Pilot projects involving battery storage systems have already connected to the national grid, offering a promising solution for smoothing out fluctuations in supply. These batteries, with a combined capacity of around 530 MW, provide an immediate response to sudden changes in demand, reducing the need for rapid deployment of conventional power sources.

While the current situation suggests that the grid can manage the demands of the upcoming summer, concerns persist regarding long-term sustainability and the pace of the energy transition. The gradual reduction in dependence on imported natural gas is part of a broader strategy to achieve energy independence, but this process requires careful planning and investment. The European Union’s initiatives, such as REPowerEU and CAN Europe PAC 2.0, outline ambitious targets for decreasing reliance on external energy sources, emphasizing the need for diversified supply chains and sustainable resource management.

As the summer progresses, the focus will shift toward monitoring the performance of newly integrated technologies and assessing their impact on overall grid efficiency. The success of these efforts will depend on continuous adaptation and innovation, ensuring that Greece can maintain a stable and secure energy supply while progressing towards a cleaner and more resilient energy future.