Russia is close to achieving a decisive edge on the energy front of the Russo–Ukrainian war. Repeated attacks on key infrastructure have recently intensified, leaving Ukraine’s damaged electrical grid 70 percent reliant on three complexes of nuclear reactors. These reactors are increasingly threatened by the instability of the grid itself and could become unsafe to operate, forcing a shutdown and grid collapse. Since Ukraine has submitted to heightened oversight by the International Atomic Energy Agency, the decision to shut down its nuclear plants if the perceived risk becomes too high may not be entirely its own.
Protecting the grid’s key substations is now the single most important priority for the survival of the Ukrainian state. By targeting electricity, Russia has made the current phase of the war an urban battle between darkness and light — and there is a clear scenario whereby darkness could triumph.
Ukrainian Demand and Supply
Temperatures in January and February in Ukraine remain well below freezing on most days. Due to the collapse of much industry, the current demand for electricity is down, though it still exceeds the remaining available supply. Winter demand is 18 gigawatts, but Ukraine is currently able to generate only 12–13 gigawatts domestically. This leads to frequent outages. Ukrainian sources report that household electricity outages in 2024 totaled nearly 2,000 hours: In November, power was down 25 percent of the time, and in December that rose to nearly 40 percent. Ukraine can make up some of the deficit by importing electricity from neighboring E.U. countries. Under existing agreements, however, Ukraine cannot import enough to meet demand. Widespread residential blackouts are frequent across the country, even when power plants and the grid are not under immediate Russian attack.
And supply seems constantly under threat: There have been over 1,000 attacks on Ukraine’s power grid since the start of the war, with Russia escalating its energy-focused attacks in 2024. A new round of bombardments in August undermined the efforts of Ukrainian authorities to restore the power supply over the summer. By September, the grid was reportedly generating only one-third of its pre-February 2022 level. Due to the repeated bombings of thermal and hydropower plants, the majority of Ukraine’s remaining electricity generation now comes from nine nuclear power plants arranged in three complexes: Rivne (four reactors), South Ukraine (three reactors), and Khmelnitsky (two reactors). Russia has been reluctant to attack these facilities directly due to the risk of releasing radioactive contaminants into the surrounding environments.
Russian Targeting of Ukraine’s Nuclear Power Plants
Russia does not need to attack the three remaining nuclear power plant complexes to collapse Ukraine’s electricity supply. The national grid is connected by 103 substations, which used to integrate electricity from several sources (e.g., nuclear, coal, gas, and hydro) but now rely mostly on nuclear power. This lack of source diversity weakens the grid, increasing the chances of cascading failure.
The substations are a vital part of the entire system. Without them, nuclear power plants can neither supply the grid nor retain the backup supply of power that is essential for reactor safety. Therefore, the loss of offsite power to a nuclear power plant is a serious problem.
To make matters worse, many of Ukraine’s substations are exposed and vulnerable, lacking adequate protection against Russian air attacks. On Nov. 28, attacks against four substations forced a temporary shutdown of one of the four reactors at the Rivne complex. The same series of attacks forced nuclear power plants at all three complexes to reduce electricity output as a precautionary measure since the resulting damage had created dangerous instabilities in the grid.
Forcing a shutdown of a nuclear power plant by attacking the surrounding substations is straight out of the Russian playbook: In September 2022, Russia compelled the closure of the Zaporizhzhia Nuclear Power Plant using similar means. By attacking nearby substations and thereby frequently interrupting the steady flow of power across a period of several weeks, Russia drove the facility to decrease output, then to supply power only to itself, and finally to lose connection to offsite power. This loss of offsite power happened repeatedly during the attacks, raising the perceived risk of an accident enough that the International Atomic Energy Agency intervened, encouraging Ukraine to close the facility, which it did in September 2022. Russia declared that it had taken control of the shuttered plant on Oct. 5, 2022. It remains in Russian hands today.
From that experience, Russia learned how the International Atomic Energy Agency might respond to a situation of heightened danger to a nuclear power plant. In fact, the agency has played a leading role in helping Ukraine manage its nuclear power since the start of Russia’s full-scale invasion in February 2022. Thus, the prospect of using the agency as a tool to compel shutdown offers a potentially attractive option to the Kremlin.
The Role of the International Atomic Energy Agency in the Russo–Ukrainian War
In response to the first-ever occurrence of heavy fighting near nuclear power plants, the International Atomic Energy Agency became involved in the war on the second day of the invasion. The Ukrainian government notified the agency on Feb. 25, 2022 that it had lost control of the Chernobyl plant, which had been managed by Ukrainian authorities since its shutdown in 1986. It also invited the agency to take on an enhanced regulatory role during the conflict.
Since that day, the agency has established an important role for itself in the war, reporting on the state of Ukraine’s power supply and working to reduce risks of a nuclear catastrophe. It has supported Ukraine generously, completing 86 deliveries of safety and security equipment worth more than $14 million. In March 2022, the agency established seven “indispensable pillars” for nuclear safety and security amid the conflict, and it has provided regular reports on dangers to these pillars ever since. The presence of “secure off-site power supply from the grid for all nuclear sites” — or pillar four — is among the most often reported. At the invitation of Ukraine, the agency has established monitoring teams at each of Ukraine’s nuclear power plant complexes, including Zaporizhzhia. The agency continues to report on the risks at Zaporizhzhia and regularly emphasizes the fact that closing the plant significantly reduced — but did not eliminate — risk.
The International Atomic Energy Agency’s nuclear safety pillars have subsequently been endorsed by all member states, including Ukraine and Russia. The office of the agency’s director general releases a press statement every time a nuclear-safety-relevant incident occurs. As of Jan. 23, 2025, there had been 271 statements on the situation in Ukraine. The agency has undoubtedly made all of Europe safer by its intervention.
This very intervention, however, suggests a potential lever for the Kremlin. The agency has become the key vehicle for providing European donor assistance to Ukraine’s nuclear power plants. Continuous agency reporting of irregularities and risks can serve to heighten European concern about possible risks to the surrounding areas of an accident or incident. Russia is clearly aware of the concern and seems to be deliberately ratcheting up the fear, including by carrying out a Dec. 10, 2024 drone attack on the vehicle of newly arrived agency observers.
The Acceptable Level of Risk
Ukraine is thus partially dependent both on the agency and on European energy ties. Beginning in 2011, Ukraine joined the European Energy Community, setting itself on a course to be fully compliant with E.U. energy law — and compatible with the massive European grid. This required steadily disengaging from the Russian grid and increasing the transparency of all energy trade with Russia. The European Energy Community, which includes all E.U. members, welcomed Ukraine’s membership, hoping that a new member with surplus nuclear generation capacity could assist with achieving Europe’s ambitious goals to increase electricity generation while continuously decreasing greenhouse gas emissions. Understanding the potential economic windfall involved, Ukraine managed to achieve and implement the difficult but necessary structural energy reforms. From 2011 to 2022, the successive disengagement from Russian energy structures and systems served to further increase tensions with Russia.
By February 2022, Ukraine had only one remaining requirement for gaining membership in the European grid: to demonstrate that it could operate its domestic grid reliably in isolation for a week. This “de-linking” (from Russia, Belarus, and Poland) had been previously scheduled for Feb. 24. Since the full-scale invasion began the same day and Ukraine went ahead with de-linking despite the attack, Ukraine’s grid continued to operate in isolation until it was accepted permanently into the European electricity grid on March 16, 2022. Thereafter, Ukraine became a net exporter, steadily exporting electricity to Europe from March 2022 through August 2022. The revenue and status Ukraine derived from those exports were significant factors in the Russian decision to increase shelling of the substations and power lines associated with the Zaporizhzhia Nuclear Power Plant. Since the closure of that facility on Sep. 12, 2022, Ukraine has become a net importer of electricity, regularly petitioning the European grid system for higher import volumes and more infrastructure. According to Ukraine’s energy ministry, Kyiv regards its energy relationship with Europe as a crucial source of imports at present — but as a critical export market in the longer term. Thus, maintaining a reputation for reliability and safe operation of its power generation is essential.
Ukraine is not the only country focused on a nuclear energy future. In fact, nuclear energy is enshrined in European law as a long-term fuel source for the green transition, and 12 E.U. states joined the United States, the United Kingdom, and Ukraine in pledging to triple nuclear energy capacity by 2050 as part of U.N. climate commitments. However, history suggests a nuclear accident caused by the war could derail a potential nuclear renaissance. The 2011 Fukushima disaster led to a collapse in the global price of uranium and had a measurable impact on the trajectory of nuclear power globally, as it compelled countries to recalculate unanticipated risks. Experts are already reconsidering the military implications of nuclear power and calling for stronger international oversight to precede new construction.
Due to the fear of an accident with local and international implications, the European Union, the United Kingdom, and the United States are likely to join with the International Atomic Energy Agency in insisting on shutting down any of Ukraine’s nuclear power plant complexes if they — or the grid to which they are connected — fail to meet international safety standards. The E.U.–Ukraine Association Agreement states, in Article 342, that Ukraine must cooperate with International Atomic Energy Agency principles and standards for nuclear safety. With the agency monitoring on the ground and releasing regular press statements, there will be little room for Ukraine to negotiate.
Ukraine’s Energy Security Options
International advisors and Ukrainian energy experts agree that the best measure Ukraine can take to avoid grid collapse is to concentrate air defense systems on protecting the key substations: Defending the grid is as critical as defending the remaining megawatts. Even the International Energy Agency, which typically focuses on the infrastructure and market development of its members, has included “bolster the physical and cyber security of Ukraine’s critical energy infrastructure” first among its priority recommendations for getting Ukraine through the rest of the winter.
While air defense in Ukraine has improved dramatically since the first year of the war, they are stretched thin. Ensuring that the systems in operation have sufficient munitions has also been a challenge. It is unclear the extent to which Ukraine has prioritized air defense for the electricity sector — although domestic and international energy sector experts have strongly advocated for it. The Ukrainian defense during the 2024 Christmas attack is illustrative: The reported success rate of destroying 65% of missiles and drones kept Russia from controlling the air, but this leaves considerable room for damage if the attacks are well-targeted.
Meanwhile, the ability to conduct rapid repairs to the grid and substations is an area in which Ukraine has excelled. Ukraine’s ability to restore power to half a million citizens within 24 hours of the Christmas day attacks was remarkable. According to experts at the Ukraine Energy Security Dialogue in December 2024, the ability to repair transformers rapidly has been dramatically improved (although it still takes 17 days). In addition, Ukraine has sought resilience through building up distributed power: Over 1.5 million power generators have been imported, 200 megawatts of energy storage has been purchased to help increase grid resilience, and some decentralized power systems are in place. Absent sufficient air defense for the grid, however, these measures may not be enough.
If Ukraine is able to make it through the winter, the coming year looks more promising. The International Energy Agency released a recent report arguing for a decentralized electricity system for the country to supplement its nuclear power. Such a system would integrate renewables, batteries, and modular gas turbines, which could significantly improve the resilience of the grid. Distributed energy resource systems are typically more difficult to target, while making it possible to generate power closer to demand centers. If sufficient investment can be found, such a system could be put into place relatively rapidly.
While Ukraine improves its own ability to generate power, it can also increase electricity imports from the European grid system. Current import levels are limited by existing contracts and infrastructure, but Ukraine’s imports expanded significantly in the past year from 1.7 to 2.5 megawatts and could be further increased in the spring. The key barriers to imports are security and cost. Russia has regularly targeted cross-border transmission lines, so increased imports must be coupled with improved air defense in additional strategic locations. Finally, like much of the country, Ukraine’s electricity sector is battling insolvency. After a year of near-constant attacks, the grid operator, Ukrenergo, had to suspend payments in November 2024. Although it is said by the Ukrainian government to be “restructuring,” the operator’s inability to pay for electricity imports serves to dampen enthusiasm for expanding exports.
The Worst Case Scenario
If keeping Ukraine’s electrical grid functioning seemingly requires huge investment, consider the cost of a failure to do so. Ukraine’s ability to keep the lights on is closely tied to both regime survival and European stability. Ukraine is 70 percent urban, with five major cities having over 900,000 residents each. Large urban areas such as these rapidly become ungovernable without electricity. The highly centralized systems in Ukraine mean that a loss of electricity puts water, sewage, and heat at risk as well, increasing the likelihood of large-scale population displacement. An estimated 6.8 million refugees have already left Ukraine, with an additional 4.0 million internally displaced. A catastrophic outmigration would create a refugee crisis across Europe, especially in neighboring states. Poland is already hosting over 900,000 Ukrainian refugees and Germany is hosting over 1.5 million. An additional nine European countries are hosting between 100,000 and 900,000 each. Europe has mostly been welcoming, but a second wave of refugees would strain the resources of even the most generous states. A full-blown winter refugee crisis could reduce Europe’s will to continue supporting Ukraine in its fight and in its negotiation of the terms of peace.
A grid collapse, should it occur, would reflect the ongoing role played by energy in this war. From the 2015 severing of Crimea from Ukraine’s electricity grid, to the 2015–2016 massive cyber attacks on Ukraine’s grid, to the destruction of the Nord Stream II pipeline, energy has factored heavily into the grievances and the ends, ways, and means of the Russo–Ukrainian war from its outset. We now find ourselves in a moment in which a slow war of attrition could come to an abrupt end, resolved by the triumph of cold and darkness. Ukraine’s survival now turns not on megatons, but on megawatts.
Theresa Sabonis-Helf is a professor at Georgetown University, and concentration chair for science, technology, and international affairs in the Masters of Science in Foreign Service program.
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