For defense planners, this presents both an opportunity and a headache. Energy is a key enabler of military operations. To maintain a warfighting advantage, planners must adopt innovative energy technologies faster than rivals. Yet navigating this complex, fast-moving and civilian-dominated sector is easier said than done. Most civilian breakthroughs offer little direct military purpose, and even fewer provide a clear operational edge.

The challenge is not a lack of options, but knowing which of them matter. Tools such as the Energy Innovation and Technology Tracker can help planners navigate the energy innovation landscape and cut through the noise. Still, every so often, a technology rises above the rest.

This article outlines three innovations which merit a closer look.

The views expressed in this article are the author’s own, are contributed in a purely personal capacity, and may not represent those of NATO.

Lukas Trakimavicius is a Policy Officer working on Energy Security at NATO HQ. Previously, he led the energy portfolio at the EU Institute for Security Studies (EUISS) in Paris, while also serving as a Non-Resident Fellow at the Center for European Policy Analysis (CEPA), based in Washington D.C. He also supported the World Energy Council’s work on energy innovation.

Before that Lukas worked at the NATO Energy Security Centre of Excellence, focusing on energy security and innovative energy tech. He also served at the Lithuanian Ministry of Foreign Affairs.

This article explores the ocean’s vastly untapped power production potential, the physical and chemical energy
forms as well as the conversion principles and technologies used. Some ocean power generation technologies
have already been exploited for decades and, in one case, centuries, with well-established technologies. Others are
currently in developing states or exist as prototypes only.

This article explains relevant technical terms followed by a technical discussion of the most intuitive technologies which harness the potential and kinetic energy of the tides and waves. Then the vast thermal energy of tropical oceans for producing electricity will be discussed as well as the technologies using spatial water salinity gradients.

NATO Allies rely on electricity supply to power estates and operations, and the way they consume it is changing rapidly. Electrification of the staff vehicle fleet is well underway, while demand is rising to support new technologies such as drones, advanced radar systems, and digital communications. Even combat vehicles are being considered for hybrid or fully electric powertrains, and directed energy weapons may soon see wider deployment. As a result, Allies must fully understand the long-term interaction between their demand profiles, national and local electricity systems, and wholesale energy markets.

Like civilian consumers, military entities have two primary options for securing electricity: generate it themselves or procure it from the grid. While many military estates and operational bases already generate electricity onsite – via diesel generators, renewables, or potentially nuclear power – most fixed infrastructure rely heavily on national electricity distribution networks. This creates a structural dependency: military capability is tied to the resilience of national grids and the ability of Distribution System Operators (DSOs) to balance loads effectively and reliably.

Data from the UK Ministry of Defence (MOD) shows a sharp 46% increase in electricity consumption between 2017 and 2023. If this trend holds across the Alliance – driven by the electrification of platforms, infrastructure, and technology – military institutions may cement themselves as the largest institutional consumers of electricity in their nations. On this trend, we could expect MOD to consume around 2.7 TWh annually by 2030, outlined in the graph below.

Source: NATO ENSEC COE Analysis of Historic Data Collated from MOD Annual Accounts

In 2017, the total electricity demand for the UK was around 300 times higher than the MOD’s consumption. However, given the projected rise in military demand, the MOD’s share of the total national electricity demand could approach 1% by 2030.

This rise in demand must be accommodated by electricity distribution infrastructure. As military electricity demand increases, local DSOs must continue to balance supply, demand, and system frequency. Large, inelastic loads must be taken into account to avoid disruption. That means infrastructure must be able to support it: the network of cables, substations, and transformers must be able to meet this changing load profile.

Source: DESNZ Energy & Emissions Projections

These issues can also impact the wholesale prices of electricity, especially as MOD consumption remains largely unaffected by price fluctuations. When large loads lack prices elasticity, it puts upward pressure on wholesale prices in a tight market. This means that reducing reliance on grid-sourced electricity – for example, through building out on-site renewables – can also have positive implications for civil consumers.

Moreover, following Russia’s full-scale invasion of Ukraine, the desire to decrease dependence on energy imports has become more prominent. With this in mind, the potential for military demand to outstrip national electricity generation growth might be a concern for Allies. The interconnectedness of European electricity markets allows for smooth distribution of power across borders; however, maintaining sufficient generation ability within borders is beneficial from a supply security perspective. If NATO nations’ generation capacities do not keep pace with growing military demands, it could increase reliance on imports, potentially destabilising energy supplies.

Source: NATO ENSEC COE Analysis of DESNZ EEP and UK MOD Annual Accounts data

If the percentage of MOD demand versus national generation increases, it becomes a more important part of the domestic power system (unless that demand is served by on-site generation). With that, the importance of electricity system resilience to national defence becomes even greater. This demonstrates why ongoing efforts to secure infrastructure against hybrid threats is critical for operational effectiveness. 

Another key factor is Host Nation Support (HNS) – the civil and military assistance provided by a host country to NATO forces and institutions during peace, crisis, or conflict. As allied forces transit or operate within host territories, particularly on the Eastern Flank, they place growing logistical and energy burdens on host nations. These burdens may be expected to increase in the coming years. National military authorities are responsible for publishing a Capability Catalogue that outlines the personnel, equipment, and duration of support they can offer to NATO. It is critical for energy availability to be fully integrated into HNS planning.

To meet future demands, Ministries of Defence, DSOs, Transmission System Operators (TSOs), and Ministries of Energy must maintain strong, long-term partnerships. Each needs a long-term understanding of demand profiles under different scenarios – especially for surge or crisis conditions – and integrate them into national energy planning processes. This mitigates the risk of unanticipated burdens on infrastructure and supports more informed investment decisions.

Moreover, there is strategic value in increasing indigenous generation capacity at military bases. Deployable and modular energy systems – microgrids, mobile renewables, battery storage – can reduce reliance on national grids, enhance operational resilience, and increase flexibility in austere or contested environments.

Without coordinated foresight, NATO Allies risk facing operational constraints or placing stress on civilian energy systems at critical moments. A shared understanding of future military power demand – and the infrastructure, cybersecurity, and market conditions required to support it – must be a core element of both defence and national energy policy.

NATO ENSEC COE Support Field Test of Hybrid Generation System – strengthening onsite generation reduces reliance on grids and promotes resilience.

Holistic Civil-Military Energy Planning:

• Integrate military electricity demand into national energy planning

• Increase indigenous generation at military sites

• Address energy in Host Nation Support (HNS) planning

• Strengthen electricity system resilience against hybrid threats

• Coordinate with DSOs and TSOs under various scenarios

The energy industry played a significant role in warfare in the First and Second World Wars. Of course, it provided the energy needed to power military operations and estates. But it also diversified into and intensified production of unexpected products & services. The British gas industry produced toluene (used in explosives), dyes (for uniforms), medicines, and motor fuels alongside its usual outputs. For its role in the war machine, the Gorleston gasworks was the target of the first airborne attack in the United Kingdom of the First World War, bombed by a German Zeppelin airship.

At the orders of military leaders, British gasworks also intensified production of hydrogen during the Second World War. The lighter-than-air gas was needed to fill giant balloons which could be deployed above civilian areas or operations for defence against air attack. However, they also had calamitous impact on electricity networks, something which was ultimately harnessed offensively. The history of barrage balloons provides a valuable case study on the mobilisation of industry, the protection of energy infrastructure, and unintended consequences.

Mobilisation of Industry

The war effort required gasworks to increase hydrogen production to fill barrage balloons and enable their defensive deployment.

Barrage balloons were used in both World Wars, but it was perhaps the Second World War where they were most significant. Their main purpose was to ensure that enemy planes had to fly higher over cities and then were less accurate and at risk of colliding with the balloons or the steel cable attached to them if they flew beneath them. To harness this capability, an independent Balloon Command was established under Air Vice Marshall Sir Leslie Gossage in 1938. It became a sizable operation, with 52 operational squadrons flying about 5,000 barrage balloons, stationed right across Great Britain.

The balloons were silver in colour because the Egyptian cotton they were made from was covered with an aluminium powder. They were sizable at 64 ft. long and weighing around 600 pounds. They consisted of two compartments separated by a horizontal gas tight diaphragm. The upper compartment held hydrogen, and lower compartment was filled with air.

The gas industry in Great Britain played an important role in supplying gas to inflate these balloons and to supplement the production at chemical works in the North of England. Sixteen gasworks were chosen to supply additional hydrogen gas in locations ranging from Pontypool to Cambridge.

Hydrogen Plant in Torquay during WWII

Image source: National Gas Archives

Barrage balloons were typically used in a defensive manner, being stationed over key cities, towns and strategic locations, flown at a height of 5,000 feet. They also played a key role in protecting the D-Day landings, seen below. The gasworks at Poole and Torquay produced most of the hydrogen required for the barrage balloons used in the D-Day landings. The picture below shows the 320th Barrage Balloon Battalion on Omaha Beach, an African American United States Army unit, flying its balloons at low altitude to prevent strafing of the beaches. Altogether about 4,000 balloon personnel, together with balloons and hydrogen, took part in the Normandy landings, transported across the English Channel to protect the artificial harbours, captured ports and ammunition dumps of the Allied forces. Lord Ashburton, Group Captain in charge of the operation wrote: “the one shortage that never hit us was lack of hydrogen.” A tribute indeed to those working at the gasworks, and the public partnership with industry to support the war effort. 

Barrage balloons over Omaha Beach at low tide, first few days after D-Day, June 1944

Image source: https://en.wikipedia.org/wiki/Barrage_balloon, Wikipedia Commons. Public Domain.

Calamitous Mistake to Offensive Capability

As the destructive potential of barrage balloons became clear, British military planners adapted them into a low-cost weapon to target enemy infrastructure.

However, while the gas industry was mobilised to produce the hydrogen required for the balloons, the electricity industry was the unwitting recipient of the unintended damage they could cause. Stray barrage balloons were reported to have caused more damage to the electricity infrastructure in the UK than the German Air Force did during the war. The main cause of disruption was the steel tether cables attached to the balloons: when these long, conductive wires came into contact with overhead power lines, they could cause short circuits, arcing, and mechanical breakage of insulators and cables. It was also possible for the balloons themselves became entangled in transmission towers, adding weight and tension that can led to structural collapse or line sagging. Supposedly, officials could even plot the course of balloons that had detached from their moorings by following the trail of blackouts and damaged substations across the grid. Ultimately, the Royal Air Force was dispatched to shoot them down to avoid further disruption and restore some measure of control over the electrical network.

From the start of the Second World War Air Vice Marshal E L Gossage, received a constant string of complaints from the electricity distributers regarding the damage done across Great Britain by stray barrage balloons. He went on to suggest that “advantages might be taken of this to impede and inconvenience the enemy.” When Winston Churchill, learned of the chaos they caused he said “if we can do this much damage by accident, what might we do on purpose.”

He immediately directed that the use of free flying balloons as a means of attacking Germany should be investigated, and the military were then tasked with planning for their use in an offensive capacity. Whilst the Air Ministry was reluctant to get involved, the admiralty was supportive. They were relatively cheap and did not risk any service personnel. It was well known that the design of the German power network made it vulnerable to damage by short circuit; the aim was to use the balloons to disrupt electrical systems in occupied Europe. The balloons would be equipped either with steel wires beneath them to damage power cables or armed with incendiary devices to cause fires in woodland.

Correct and accurate weather knowledge was required since balloons would only go where the wind would take them; they were in effect unguided weapons which could do indiscriminate damage. Planners determined, however, that the winter winds above 16,000 feet blew towards the continent and would be the best option to carry the balloons in the desired direction. Different types of balloons were used for offensive purposes than the defensive barrage balloons. Simpler models were made from latex, filled with hydrogen and fitted with a simple fuse system to control height and flight duration. They also dragged a 300 ft. section of 15-gauge steel piano wire.

These offensive balloon launches started in March 1942, from the east and south east coast of Great Britain. At the operation’s height, over 1,000 balloons were released per day. Whilst they inflicted significant damage to German infrastructure, national representative did not comment. The neutral countries of Sweden and Switzerland, however – who were also in the path of these balloons – complained bitterly through diplomatic channels of the considerable damage they caused to their overhead electricity lines.

Ultimately, the story of barrage balloons in the Second World War highlights the importance of co-ordinated planning between the military and civil sectors to avoid harmful unintended consequences. Moreover, it is clear that flexibility and responsiveness of industry played a major role in meeting evolving demand and enhancing capability.  

Four Lessons from the Barrage Balloon Campaign

1. Energy Infrastructure Has Been and Will Continue to be a Target

The vulnerability they exposed at home swiftly led to their repurposing as weapons abroad.
This gives us an archetypal example of the need to harden physical protection of energy infrastructure against the full range of threats.  Today, this extends to cyber.

2. Industrial Capability Can Enhance Security

The success of British gasworks’ rapidly scaling hydrogen production underscores the value of flexible, responsive industrial capacity in national resilience.

3. The Importance of Civil-Military Coordination

Tensions between military and civil institutions (e.g., over balloon-caused outages) highlight the need for holistic planning and clear lines of communication.

4. Dual-Use Technology

Tools designed for one purpose, such as defence, can have unforeseen applications. Modern parallels include AI, drones, and cyber tools that can be misused.

Chapter 1 provides a comprehensive definition of these terms and examines the impact of energy infrastructure on soldiers in the field. It also reviews recent NATO efforts to enhance energy security.

Chapter 2 delves into the various types of CEI, including land and maritime infrastructure, highlighting the significance of regions like the South China Sea in CEI security. Additionally, it examines the current state of Italy’s underwater CEI and the gaps in understanding that remain. The paper concludes with a discussion on potential future actions by NATO to address the vulnerabilities of CEI, emphasizing the need for strategic measures to safeguard military operations and missions from infrastructure threats.

Current Situation Analysis

The programme consists of over 20 projects to strengthen the Baltics’ electricity network. New high voltage transmission lines have been constructed to carry power through the region. These also facilitate interconnection with EU neighbours, with one project expanding the LitPol Link between Lithuania and Poland. Nine synchronous condensers and six large-scale battery storage systems (some scheduled for 2025) have been introduced. [2] Condensers (giant wheels in constant rotation) provide instantaneous energy to the system or absorb excess in times of stress. Batteries respond to short-term changes in supply and demand. Together, they will help maintain frequency and system balance. In addition, nine connections with Russia and Belarus will be disconnected (See Annex A).

Figure 1: Baltic Installed Electricity Generation (2019-2025) & Breakdown

Figure 2: Baltic Electricity Capacity Margin

Source: NATO ENSEC COE Analysis of ENTSO-E Transparency Platform [3]

Since the programme’s commencement, the Baltics have increased electricity generation capacity by 42%, now totaling over 13GW. Growth has primarily been driven by renewables, particularly wind and solar (Figure 1). However, renewables depend on the weather. The capacity factor for renewables in the region (how much they actually generate versus the installed maximum) is 28%. Oil shale & gas generators have higher availability and can be turned up and down at short notice. De-rated capacity (how much generation we could expect in times of high demand) is 6.2GW, healthily above the 5.2GW peak demand the TSOs have calculated. [4] Importantly, this does not include potential supply from EU neighbours, which provides extra contingency.

The Baltics share interconnection with Sweden (0.7GW), Poland (0.5GW), and Finland (1GW). A further 0.7GW is planned between Lithuania and Poland (‘Harmony Link’, originally planned to be a marine cable, will now be developed over land).

In addition to infrastructure changes, the programme includes several market reform projects, including the planned launch (February 2025) of a frequency reserve capacity market. [5] This is to ensure it is economically viable for market participants to provide the system with energy in times of stress. Baltic electricity TSOs have signed a regional system management agreement, which describes the principles of cooperation after the synchronisation. [6] Its purpose is to ensure reliable operation, optimal management and technical development of the Baltic States’ electricity systems.

Challenges

Despite adhering to contractual obligations, it is possible that Baltic States may face targeted disruption to their electricity networks as a result of BRELL disconnection. Geopolitical commentators have highlighted the risk that Russia will unilaterally disconnect from the BRELL system in advance of the target date, motivated by the risk to their reputation. [7] They have also noted the precedent of sabotage and cyber-attacks to the Baltic States during disagreements with Moscow. [ibid] With no land border between Kaliningrad and mainland Russia, Kaliningrad will also disconnect from BRELL at the same time. Russia has built new coal and gas stations in Kaliningrad to prepare extra capacity to run as an island. Concerns about the security of subsea electricity cables have also been raised, with several recent disruptions to the interconnector with Finland. [8] 77% of interconnection capacity between the Baltic States and EU neighbours is made up of subsea cables.

All three countries have carried out advanced contingency planning, such as testing isolated operation of their own power systems to ensure they can run without BRELL connection. [9] In 2023, average hourly consumption across the year in the region was 2.8GWh. [10] Figure 2 demonstrates that, barring significant simultaneous disruption to multiple elements of the system, the Baltics are in a strong position to be able to meet demand after BRELL desynchronisation.

Nonetheless, interconnection with EU neighbours provides desirable contingency. Recent damage to the Estlink-2 interconnector means a loss of 0.65GW potential supply for the remainder of this winter, with repairs to take ‘several months’ according to Finnish TSO Fingrid. [11] While Estonian TSO Elering is confident this will not negatively impact desynchronisation [12], its timely repair will take some pressure off the Baltic system.

Gap Analysis & Next Steps

The 20 projects agreed under the synchronisation programme have largely proceeded without fault. Primary disruption has been in the construction of the Harmony Link between Poland and Lithuania. Originally intended to be a marine cable, this idea was scrapped in April 2023 owing to a “significant increase in costs and orders for submarine cables and converter stations.” Given the recent vulnerabilities seen in subsea cables, this is not a bad development. However, the problem lies in the timeline: the engineering plan for an overland cable will not be completed until the end of 2026. Harmony Link has the potential to increase interconnection capacity with EU neighbours by 32%, and entirely via overland connection. Completion of this project must therefore be facilitated.

Nonetheless, it is likely that, without large-scale and targeted disruption to the regional network, the Baltics will be able to comfortably balance electricity supply with demand after BRELL disconnection. The programme’s completion will significantly reduce Russia’s direct influence, bolstering sovereignty and security. [13]

Annex A: Map of Baltic Electricity Network & Synchronisation Projects

Source: Latvian TSO [2]

Bibliography

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