Energy and War

The dependency of military power on energy is one of the oldest and most consistent facts of modern warfare, and one of the most consistently underestimated in public strategic discourse. Battles are analysed in terms of tactics, command decisions and weapons technology. The logistical chains that supply the fuel to keep tanks moving, aircraft flying, ships sailing and factories producing are treated as background conditions rather than decisive variables. They are not. In every major conflict of the industrial era, the management of energy supply has been a primary determinant of operational capability, and its failure has been a primary cause of military defeat. Germany's inability to secure adequate oil supplies after 1943 constrained its operational flexibility more severely than any Allied tactical innovation. Japan's vulnerability to submarine interdiction of its oil supply lines from Southeast Asia accelerated its strategic collapse before the atomic bombs were dropped. The lesson is consistent: energy is not the enabling condition of military power. It is its binding constraint.

Oil remains the single most important energy source for military operations, and its dominance in this role is unlikely to change materially within any planning horizon relevant to current strategic decisions. Modern armed forces are heavily mechanised in ways that create structural dependence on liquid petroleum fuels whose energy density, storability and adaptability across multiple platforms have no viable large-scale substitute in high-intensity military operations. Armoured vehicles consume diesel at rates that scale rapidly with operational tempo. Military aviation consumes jet fuel in quantities that place enormous pressure on forward logistics. Naval vessels, despite their scale, require continuous fuel resupply for extended operations. Ground logistics, the trucks and aircraft that move ammunition, spare parts, food and personnel, consume fuel continuously throughout any sustained campaign.

The scale of consumption in major military operations is difficult to convey in conventional terms. The United States military is the single largest institutional consumer of petroleum products on earth, consuming approximately 100 million barrels of oil annually in peacetime. During Operation Iraqi Freedom in 2003, the US-led coalition consumed fuel at rates that required a logistics network involving hundreds of tanker trucks operating continuously. In Ukraine, the sustained artillery campaign consuming hundreds of thousands of shells monthly also requires enormous quantities of diesel to move those shells from production facilities to forward positions. Russia's ability to sustain its military operations for four years is in part a direct function of its status as the world's second-largest oil producer, providing both the fuel for its military machine and the export revenue to fund it. Ukraine's ability to continue fighting is directly supported by fuel imports financed by Western assistance. Energy and finance in wartime are not separate systems. They are the same system.

While oil powers mobility, natural gas sustains the industrial production capacity on which sustained warfare depends. Gas is the primary fuel for electricity generation across much of Europe and Asia, and it underpins the industrial processes required to produce the steel, aluminium, chemicals, explosives and specialised metals that defence manufacturing requires at scale. In wartime, the distinction between civilian and military energy demand collapses. A factory producing ammunition uses electricity and gas from the same grid as a hospital. A steel plant producing armour plate draws on the same energy networks as a residential district. Disrupting energy supply disrupts the entire economic system simultaneously, without discrimination between its military and civilian components.

Russia's weaponisation of natural gas supply to Europe between 2021 and 2022 provided the most comprehensive real-world demonstration of energy as a coercive instrument in the contemporary period. By reducing and ultimately halting gas flows through Nord Stream and other pipelines, Russia imposed immediate economic costs on European economies, triggered a Europe-wide energy crisis that drove electricity prices to record levels and created political pressure on European governments to limit their support for Ukraine. The strategy was partially effective in the short term and ultimately counterproductive in the longer term, as it accelerated European diversification away from Russian energy dependence at a pace that would not otherwise have been politically achievable. But the episode demonstrated beyond analytical dispute that natural gas supply is a weapon of strategic coercion whose effects on industrial capacity and political will can be comparable to conventional military pressure applied at the front line.

Electricity has become indispensable to the conduct of modern warfare in ways that would have been structurally incomprehensible to military planners a generation ago. Advanced military systems are built around electronic infrastructure: communications networks, radar installations, satellite ground stations, data centres processing intelligence feeds, electronic warfare systems disrupting adversary communications and the autonomous drone systems that are now reshaping tactical operations across multiple conflict theatres. Every one of these systems requires continuous, stable electrical power. Even brief interruptions degrade operational capability in ways that are disproportionate to the duration of the outage, because military networks depend on synchronisation and continuous data flow that cannot easily be paused and resumed.

Ukraine's experience since 2022 provides the most extensively documented contemporary case study of systematic attacks on electrical infrastructure as a deliberate military strategy. Russian missile and drone strikes specifically targeted power generation, transmission and distribution infrastructure throughout the conflict, with the strategic objective of degrading Ukraine's ability to sustain industrial production, maintain military communications and preserve civilian resilience. By mid-2024, Ukraine's power sector had lost an estimated 38 per cent of its pre-war generating capacity to direct military strikes. Peak winter demand periods created conditions in which the remaining grid capacity was insufficient to meet demand, requiring rolling blackouts that affected both civilian populations and military-adjacent industrial facilities simultaneously. Ukraine's ability to sustain this pressure without military collapse is itself a testament to the resilience of dispersed infrastructure and the effectiveness of Western emergency energy support, but the strategic logic of the Russian campaign is not in doubt: destroy electricity, and the digital battlefield goes dark.

Energy infrastructure has always been a high-value target in warfare, but its strategic centrality in contemporary conflict reflects both the increased energy intensity of modern military operations and the growing physical accessibility of energy infrastructure to long-range precision weapons and drone systems. The combination of guidance technology that can strike a specific generator within a large facility and drone systems affordable enough to be used in large quantities has fundamentally altered the cost-benefit calculation for infrastructure targeting. In earlier eras, destroying a major power plant required a sustained bombing campaign that consumed significant military resources. In 2025, Iran-designed Shahed drones costing a few thousand dollars each can destroy turbines worth tens of millions, and can be produced and deployed in sufficient quantities to sustain a campaign of infrastructure attrition over months or years.

Energy prices play a central role in the economics of conflict in ways that extend well beyond the direct cost of military fuel consumption. Rising oil and gas prices increase the cost of military operations across every energy-consuming dimension simultaneously, from vehicle fuel to factory electricity to the heating of military installations. They also affect broader economic conditions in ways that create secondary strategic pressures. Inflationary energy costs reduce the real value of defence budgets without any nominal reduction in spending. They create domestic political pressure that constrains governments' ability to sustain military expenditure over time. And they affect the alliance politics of coalition warfare, as the economic costs of sustained energy price elevation fall differently across coalition partners depending on their import dependency, their industrial structure and their fiscal resilience.

For energy-exporting states engaged in or supporting conflict, high energy prices provide additional revenue that can partially offset the direct fiscal costs of military operations. Russia's ability to sustain the Ukraine war for four years while under the most comprehensive Western sanctions regime ever imposed on a major economy is directly attributable to the fact that oil and gas revenues, even at reduced volumes due to sanctions-related discounts, continued to flow at levels sufficient to fund military expenditure. The oil price cap mechanism introduced by the G7, attempting to limit Russian revenues without cutting off global supply, reflected an understanding that energy economics and military finance are the same problem viewed from different angles. Its effectiveness has been limited by the circumvention mechanisms documented elsewhere in this edition, but its strategic logic is sound: cut the revenue, and the military machine runs dry.

The global transition toward renewable energy is beginning to influence military planning and procurement, though its implications for active conflict operations remain limited and are likely to remain so for the foreseeable future. Electric vehicles, hydrogen fuel cells, distributed solar generation and advanced battery storage are all being explored across multiple military establishments as ways to reduce dependence on traditional fuel supply chains whose vulnerability has been repeatedly demonstrated in recent conflicts. Reduced fuel consumption lowers the logistical burden of sustained operations. Distributed energy generation reduces the vulnerability to single-point infrastructure attacks. Battery-powered vehicles produce lower acoustic and thermal signatures that complicate adversary targeting. These are genuine operational advantages, and military establishments are beginning to integrate them into procurement planning.

The practical constraints, however, are severe enough to ensure that fossil fuels will remain dominant in military applications for at least the next two decades. Energy density, the amount of energy stored per unit of weight or volume, remains the decisive characteristic for military applications where range, payload and operational tempo are paramount. The energy density of jet fuel is approximately 100 times greater than that of current lithium-ion batteries. An electric tank with current battery technology would carry a battery system weighing several times more than its conventional fuel equivalent, for a fraction of the operational range. The resupply logistics for electric military fleets in contested environments present challenges that have no ready solution. Military energy transition is not a question of will or policy preference. It is a question of physics, and the physics are not yet cooperative.