- Germany’s heavy reliance on imported energy, marked by the 5 May 2026 “Energy Dependence Day”, is a structural weakness that exposes the economy, social stability, and military readiness to volatile markets and weaponised supply chains.
- Diversifying suppliers is not enough. Real resilience treats energy efficiency as a security capability in its own right, lowering baseline demand, reducing import needs, and enabling the decentralisation of critical infrastructure.
- By embedding energy efficiency into national security thinking, Germany and the EU can strengthen strategic autonomy, decouple industrial output from external shocks, and defend their technological edge in an era of geopolitical competition.
In 2026, Germany’s “Energy Dependence Day” was on May 5th. From that point onward, the country relied entirely on external energy supplies to sustain its economy, maintain social stability and support military readiness. In practical terms, Germany can cover its energy consumption through domestic sources for only the first 125 days of the year; for the remaining 248 days, the functioning of Europe’s largest economy depends on imported energy and the stability of global supply chains.
This makes Germany particularly exposed within the European Union. On average, EU member states can meet their energy demand with domestic sources until June 5th, roughly one month longer than Germany. This gap reflects the country’s high industrial energy demand, its historically strong reliance on imported fossil fuels, and the limited availability of domestic energy resources.
Taken together, these figures point to a fundamental strategic vulnerability. Germany’s economic performance, societal resilience, and defence readiness remain closely tied to volatile global energy markets and geopolitical developments beyond Europe’s control. The weaponisation of energy supplies by Russia and the disruption of key maritime routes, most recently illustrated by the closure of the Strait of Hormuz in the context of the US-Israel-Iran War, demonstrate how quickly external shocks can reveal systemic exposure.
Other critical chokepoints, including the Bab al-Mandab Strait (Red Sea), the Strait of Malacca (Indian Ocean and Pacific Ocean), the Turkish Straits, the Danish Straits, the Suez Canal, and the Panama Canal underline that such risks are not exceptional events but structural features of the current geopolitical environment. Each of these chokepoints can potentially be weaponised by state and non-state actors in the future. This particularly applies given that Iran’s resistance against the United States and Israel has handed a blueprint to other countries facing asymmetrical warfare.
Beyond deterrence and defence in peace, crisis, and war, Germany faces a further challenge. The Federal Republic is stepping up its role in NATO and has to provide “Host Nation Support” for allies staying in or transiting through Germany. Refuelling and hosting transiting allied forces means Germany’s energy demand is not only its own, but must partly underwrite allied mobility. This aligns with Germany’s approach to “Comprehensive Defence”, where the country outlines that it is crucial to ensure essential state, economic, and societal functions, among them a secure energy supply.
In this context, reducing dependence on external energy sources becomes a central and short-term security imperative. While diversification of supply remains necessary, it cannot eliminate underlying vulnerabilities. A more comprehensive solution lies in reducing overall energy demand itself, thereby lowering exposure to external shocks at its source.
Energy Efficiency as a Strategic Security Lever
While diversifying energy supplies and strengthening the protection of critical infrastructure are essential steps toward enhancing German and European energy security, these measures alone cannot eliminate structural vulnerability. Reliance on external suppliers entails inherent strategic risks, as they may leverage their position to pursue broader geopolitical objectives. In an era defined by geo-economic competition, efforts to diversify supply chains must therefore be complemented by a systemic strategy to reduce dependence on supply chains altogether.
One of the most effective, and still underestimated, ways to achieve this is to reduce overall energy demand through greater energy efficiency, improved energy management, and increased energy productivity. Every unit of energy saved directly reduces import requirements and, in turn, diminishes exposure to volatile global energy markets and external supply disruptions.
This logic is particularly relevant in the military domain. Modern armed forces are inherently energy-intensive institutions, with operational readiness across air/space, land and naval forces, as well as the cyber and information domains, which are dependent on a continuous and reliable energy supply. Dependence on imported fuels creates significant logistical and strategic vulnerabilities, as fuel supply chains are often among the most exposed elements of military operations.
At the same time, the military operates extensive infrastructure portfolios that form the backbone of deployment capabilities. The German Bundeswehr alone manages approximately 1,500 sites and 34,000 buildings, covering an area larger than the State of Saarland. As one of the country’s largest public infrastructure operators, ensuring the energy resilience of this estate is a core strategic requirement.
Beyond reducing import dependence, energy efficiency also strengthens the resilience of critical infrastructure, though the relationship is more nuanced. Efficiency and resilience can pull in opposite directions: a resilient system needs redundancy and reserve capacity, which a narrow focus on efficiency might optimise away. Ukraine’s experience since 2022 has shown that systems with built-in redundancy withstand sustained attacks for longer.
The decisive point, however, is that efficiency lowers the baseline the system has to defend in the first place. A lower baseline is easier and cheaper to make redundant, and it makes decentralisation feasible. When buildings and sites consume less, a larger share of their demand can be met by on-site or community-scale generation, such as rooftop solar, storage, or combined heat and power, rather than requiring supply drawn from large, distant, and centralised assets.
The more decentralised the infrastructure, the fewer people a single disruption, whether an accident or a hybrid attack, can affect at once, and the faster supply can be restored, because fewer households need attending to and local generation can carry part of the load while repairs are underway. Together, these effects reduce the likelihood of cascading failures and improve the ability of systems to absorb and recover from disruptions.
The January 2026 arson attack on a cable bridge in Berlin’s Lichterfelde district illustrates the opposite case: damage to a single set of high-voltage cables cut power to 45,000 households and 2,200 businesses across the city’s southwest for up to four days, the longest outage since 1945. Citizens were left without electricity and heating in freezing temperatures and businesses were forced to temporarily suspend activity.
The strategic benefits extend further. Investments in energy efficiency, including in buildings, industrial process heat and transport, can reinforce Europe’s technological leadership and industrial base. Scaling the deployment of advanced insulation, high-temperature heat pumps, and digital energy management systems supports domestic value creation while reducing exposure to increasingly concentrated global supply chains, particularly in light of China’s dominant position in key clean energy technologies.
Energy efficiency should therefore be recognised as a core strategic capability that underpins both civil and military security. In an era of great power competition and contested supply chains, structural demand reduction is not merely an economic or environmental objective, it is an indispensable pillar of national and European resilience.
Energy Efficiency as the ‘First Fuel’ of Strategic Resilience
Consequently, energy efficiency should be treated as what Fatih Birol, Executive Director of the International Energy Agency, has termed the “first fuel” of a resilient economy, society, and military. It represents a critical domestic energy resource that complements renewable generation yet remains significantly underutilised. A persistent strategic misconception is that energy independence can be achieved primarily through the rapid expansion of renewable electricity and electrification. In reality, efficiency improvements are an indispensable accelerator of renewables integration, as they reduce overall demand and enable domestic clean energy sources to cover a larger share of consumption.
By structurally lowering total energy demand, efficiency measures reduce the baseline against which all energy supply must be secured. This creates a powerful leverage effect: any given volume of domestic renewable generation accounts for a larger share of the overall energy mix. Germany’s experience illustrates this dynamic. Without the efficiency gains achieved over the past fifteen years, the country’s share of renewable electricity would be closer to 35% rather than the roughly 50% reached today.
This effect scales directly to the European level. According to calculations by Jan Rosenow from the University of Oxford based on ODYSSEE-MURE data, without past efficiency improvements, the European Union would require approximately 31% more energy today and would incur correspondingly higher costs to secure it. Since 2000, efficiency gains have reduced European energy demand by around 265 million tonnes of oil equivalent (Mtoe), a volume exceeding the combined annual consumption of France and Poland.
These dynamics have direct strategic implications. Structural improvements in energy efficiency strengthen economic resilience, reduce exposure to volatile global energy markets and expand the fiscal space required to finance public goods, including defence. In this sense, energy efficiency is not a constraint on industrial activity or societal prosperity, it is a foundation of economic strength, strategic autonomy and long-term societal stability.
Operationalising Energy Efficiency as Security Policy
Recognising energy efficiency as a strategic security lever requires translating this insight into concrete policy frameworks. Conceptually, investments in defence-relevant structural energy efficiency fit within the 1.5% of GDP target for “civil preparedness and resilience” agreed at the 2025 NATO Summit in The Hague. The case rests on NATO’s own practical resilience criteria, which centre on sustaining essential state and societal functions during crisis and war.
Energy efficiency serves these criteria directly. Highly insulated buildings extend the period over which hospitals, command nodes, and civilian populations can function during a prolonged grid failure, converting hours of resilience into days, while reduced fuel demand lessens the exposure of the logistics chains on which operational readiness depends. Anchoring efficiency investments within this security framework would acknowledge their role in strengthening economic resilience and protecting critical infrastructure and reducing exposure to external supply shocks. At the same time, it would ensure closer alignment between energy policy and the broader defence and national resilience architecture of NATO member states.
1. Reducing Import Dependence and Strengthening Strategic Autonomy
Energy efficiency represents one of the most direct and effective mechanisms for reducing Europe’s structural dependence on imported energy. In 2025, the European Union spent approximately €396 billion on fossil fuel imports. As a result of the US-Israel-Iran War, in March 2026 the EU spent an additional €24 billion on energy imports due to higher prices compared to March 2025, without receiving a single extra molecule of energy.
By delivering cost-effective efficiency gains and lowering overall consumption, Germany and the European Union can reduce their exposure to volatile global markets and geopolitical disruptions. Structural demand reduction thus decouples domestic industrial output from external price shocks and supply interruptions. Every unit of energy saved is functionally equivalent to additional domestic energy production, strengthening strategic autonomy without requiring new and potentially vulnerable external supply chains.
This approach stands in clear contrast to policies that focus primarily on supply diversification. In the aftermath of Russia’s invasion of Ukraine, Europe replaced large volumes of Russian gas with alternative suppliers, including LNG from the United States and Qatar, as well as pipeline gas from Norway and Azerbaijan. While this rapid diversification was necessary to stabilise the energy system in the short term, it largely substituted one form of external dependence for another. In fact, overall import dependence in Germany and across the European Union has remained high and, in some cases, increased.
As a result, Europe’s industrial base, including the security and defence industry, continues to be highly exposed to geopolitical disruptions and price volatility in global energy markets, undermining manufacturing competitiveness and economic stability. Structural demand reduction through energy efficiency addresses this vulnerability at its root by lowering the total volume of energy that must be imported in the first place.
2. Strengthening Infrastructure Resilience and Civil Preparedness
Energy efficiency also strengthens the resilience of critical infrastructure by reducing stress on the energy system. As Germany and Europe continue to invest in strengthening energy infrastructure, particularly electricity grids, lower baseline demand allows networks to operate in a more stable manner and reduces the risk of cascading failures during disruptions. While decarbonisation through electrification will inevitably increase overall infrastructure demand, efficiency improvements simultaneously enable the development of more decentralised energy architectures. This shift distributes operational risk across multiple nodes rather than concentrating it in a limited number of vulnerable, centralised assets.
Building a resilient energy system requires substantial redundancy, often necessitating reserve capacity of up to 120% of normal demand. Financing such redundancy for a large and inefficient energy system would impose significant costs on public budgets. By reducing both baseline and peak consumption, the overall scale of the energy system and therefore the cost of securing it declines proportionally. Energy efficiency, combined with more flexible demand-side management to shift loads, can thus limit capital requirements and free up resources for economic investment, technological innovation and even defence capabilities.
These resilience benefits are particularly evident in the buildings sector. Highly insulated building envelopes significantly slow the rate of heat loss during a winter blackout, allowing residents to remain safe for days rather than hours without external energy supply. By extending this critical buffer period, energy-efficient buildings reduce pressure on emergency services and provide grid operators with valuable time to restore power. A society that requires less energy to maintain basic functions is therefore inherently more resilient to disruptions caused by technical failures, natural disasters or hybrid attacks.
The previously mentioned power outage in the southwest of Berlin once again highlighted the vulnerability of critical infrastructure when confronted with acute shocks. Particularly older buildings cooled down significantly faster than renovated buildings as outside temperatures of minus eight degrees celsius quickly dropped temperatures inside buildings to single digits.
These considerations are particularly important in an era characterised by hybrid warfare, cyberattacks, and targeted sabotage of critical infrastructure. Germany’s and Europe’s energy systems remain highly centralised, meaning that disruptions affecting key generation or transmission nodes can cascade across entire regions. As Europe transitions toward a more decentralised energy system, reducing structural demand through energy efficiency will be essential for safeguarding economic stability and strengthening civil preparedness and national resilience.
3. Preserving European Industrial Leadership
Energy efficiency represents one of the few areas of the energy transition in which Europe continues to hold a decisive technological advantage. The experience of renewable energy technologies offers a critical strategic lesson. Although European companies pioneered much of the innovation behind solar photovoltaics and wind power, manufacturing capacity and supply chains gradually shifted, particularly to China, thanks to significant state support and subsidies. This led to a high degree of global market concentration.
Energy efficiency technologies present a key opportunity to avoid repeating this strategic loss. European firms remain global leaders in areas such as industrial heat recovery, advanced building insulation, digital energy management systems, and smart grid solutions. Importantly, many of these technologies also have direct military applications that enhance operational effectiveness.
For example, the Deployed Energy Management System used by the United Kingdom’s Ministry of Defence is a rapidly deployable microgrid solution that integrates renewable generation and storage to optimise power use. In operational environments, such systems can deliver fuel savings of up to 35% and reduce maintenance requirements by around 50%. Strengthening this sector will therefore not only preserve domestic industrial value creation but also secure technological capabilities that are critical for both Europe’s energy transition and modern defence systems.
Beyond technological leadership, energy efficiency also functions as a powerful economic driver. In Germany alone, the sector supports more than one million jobs and represents a significant source of growth. According to calculations by Prognos AG, energy-efficient renovation of the building stock accounts for approximately 2.5% of Germany’s GDP, with the potential to increase to around 3.4% if renovation rates are moderately accelerated. Maintaining and expanding this industry ensures that critical engineering expertise, manufacturing capacity and intellectual property remain anchored within Europe.
Internalising Energy Efficiency as the First Fuel of Security
Energy efficiency is no longer solely an environmental policy objective. In a geopolitical landscape increasingly shaped by weaponised supply chains, hybrid threats and volatile global energy markets, the capacity to use energy efficiently has become a central determinant of national resilience and strategic autonomy.
By systematically integrating energy efficiency as the First Fuel of security into its national security architecture, Germany can reduce its exposure to external supply shocks, strengthen the resilience of critical infrastructure, and shield its industrial base from global price volatility. At the same time, expanding the domestic energy efficiency sector would help preserve European technological leadership and sustain high-value industrial activity within the European Union.
Concrete policy recommendations are available here:
This background article provides the analytical foundation for the policy brief “The First Fuel of Security: Energy Efficiency and Germany’s Path to Strategic Resilience,” published by DENEFF – the German Industry Initiative for Energy Efficiency (Deutsche Unternehmensinitiative Energieeffizienz e. V.). While the policy brief outlines concrete legislative recommendations for the Federal Republic of Germany, this document analyses the underlying structural and strategic context.
The analytical work was a collective effort by Henning Ellermann, Fabian Hoppmann, and Christian Noll from DENEFF; Sabrina Schulz and Rosa Melissa Gehrung from the European Initiative for Energy Security; and RAIA Managing Director and Partner at Western Bubble Insights & Strategy Dario Hasenstab. The findings in this paper were first presented as a discussion paper in the German Parliament, where colleagues from the NATO Energy Security Centre of Excellence and Bundeswehr Consulting provided valuable feedback and thoughts.
