Chornobyl, ZNPP, and Blackouts: What the October Attacks on the Energy System Mean

Early October 2025 marked the resumption of massive aggressor attacks on Ukraine’s energy infrastructure. For the first time since the spring shellings, the country once again faced large-scale power outages.

In the Chernihiv region, for instance, a “6/3” schedule has been implemented, meaning six hours with power and three without. In the Kyiv, Sumy, and Odesa regions, disruptions to electricity and water supplies are being reported. In Odesa alone, over 46,000 consumers were left without power.

The attacks are accompanied by systematic pressure on critical nodes of the energy system—both on generating capacities and distribution facilities.

This signals the beginning of a new phase in the “energy war” against Ukraine. Unlike in previous years, the campaign against Ukrainian energy is unfolding with the experience of past winters in mind and a deliberate selection of targets.

The Enemy’s Strategy: Strikes on Energy Infrastructure and Nuclear Pressure

It is already clear that the enemy has shifted its focus. While in 2022–2024 the main targets of air attacks were large thermal power plants, today they are nuclear power facilities and the critical substations that supply them.

The precision strike on the substation in Slavutych, which provides power to the Chornobyl Nuclear Power Plant (ChNPP), was a sign of direct nuclear blackmail. Following the attack, the ChNPP experienced a complete power outage lasting over three hours. Nuclear fuel storage facilities and the protective structures over the destroyed 4th power unit were left without electricity.

Unfortunately, such actions are not isolated psychological acts but are systematic. The aggressor is attempting to use the vulnerability of nuclear infrastructure as a tool of pressure—including to achieve its own goals of restarting the temporarily occupied Zaporizhzhia Nuclear Power Plant (ZNPP).

The Situation at the ZNPP: Risks Remain

As of September 23, the ZNPP was left without external power. The fuel reserves for its diesel generators were sufficient for approximately 10 days. At the same time, a complete shutdown of backup systems creates a risk of nuclear fuel overheating, as proper cooling requires a constant connection to the grid.

However, the technical parameters of the plant allow for avoiding critical scenarios for some time. All ZNPP power units are currently in a cooled state, and even in the worst-case scenario, a “Fukushima-style” catastrophe is ruled out. For the reactors to reach dangerous temperatures (over 500°C), at least two months of continuous heating would be required, which is unlikely given the existing heat removal systems.

But this does not mean the situation has become completely safe. The plant’s power supply has not been fully restored. Furthermore, according to the IAEA, a series of explosions was recorded near the plant, increasing nuclear risks. Most importantly, there is currently no precise information about the exact condition of the plant’s safety systems.

Nuclear Power Plants Under Load: Will They Withstand?

Due to significant losses in thermal generation, the main load on the system today is carried by nuclear power plants in the controlled territory.

During peak hours, a significant portion of the electricity in Kyiv and the central region of Ukraine comes from the Rivne and Khmelnytskyi NPPs, which creates new threats. The substations and power lines connecting these plants with high-demand consumers become critically important. It is these targets that the enemy is trying to disable with precision strikes.

The vulnerability of such facilities is one of the main problems of the autumn-winter period. Even the capital, despite its powerful air defense system, remains dependent on energy facilities outside its borders—primarily thermal power plants that lack effective protection.

Current Status: Is the System Ready for Winter?

Despite the growing threats, Ukraine’s energy sector entered October with quite high indicators of preparation for the winter season. 12.7 billion cubic meters of gas have been accumulated in underground storage facilities, and the planned level of 13.2 billion m⊃3; is expected to be reached by the end of the month. Coal reserves are estimated at 2 million tons.

In total, 2.3 GW of generation has already been restored in Ukraine, with another 3.7 GW planned for commissioning, and 1.8 GW of distributed generation capacity has already been implemented.

All these measures allow us to speak of the system’s increased flexibility and resilience, especially considering the efforts toward decentralization and integration with the European energy market.

So, despite 65,000 instances of damage to energy infrastructure recorded since 2022 (3,500 of which occurred in 2024 alone), the system continues to function. This demonstrates its exceptional ability to adapt, despite direct losses estimated at $20 billion.

The Main Thing: Grid Stability and Distribution Protection

Thus, the most critical areas from a protection standpoint can already be identified. The most vulnerable remain the distribution networks and substations that lack proper physical or electronic protection. It is these facilities that become the primary targets of massive drone and missile attacks.

A separate risk is the overheating of local networks in case of overload. Under such conditions, even minor damage can lead to cascading outages at the district or regional level.

Will There Be Blackouts?

Recently, “Ukrenergo” appealed to Ukrainians not to turn on several powerful appliances simultaneously during peak load hours (from 17:00 to 22:00). Such behavior helps reduce the load on the grid and avoid emergency shutdowns. However, these are recommendations long familiar to consumers and do not cause particular concern.

Currently, experts describe three basic scenarios for the 2025/2026 winter:

• Optimistic: Air defense systems successfully counter most attacks, and any power outages are localized and short-term.
• Moderate: Massive strikes create a generation deficit, leading to the implementation of scheduled outages for 4-8 hours per day.
• Pessimistic: Simultaneous attacks on power plants and distribution systems, cessation of electricity imports from the EU, with the threat of a nationwide blackout.

However, it should be noted that the threat of a national blackout this winter is low. The Ukrainian energy system has repeatedly proven its viability despite air attacks. Therefore, the most likely scenario is controlled, scheduled outages in specific regions. A full-scale blackout, according to the system operator’s data, is not expected.

This, however, does not apply to the vulnerable border regions—Sumy, Chernihiv, and Kharkiv. They are already suffering from systematic electricity supply disruptions. Some facilities in the central part of the country, particularly those supplying large cities, also remain under threat.