Sustainable energy for Defence


On 15 February 2023 EDTA and the Eurodefense network sent "Recommendations on Energy, Security and Defence" to the presidents of the European Commission, the European Council and the European Parliament. 

The recommendations are a report of a joint working group (EWG26B) and consist of Geopolitical Considerations, European Energy policies proposals and a technological perspective

For EDTA the technological perspective is the most relevant part. Continue reading for this part of the executive summary and for recommendations on technology, specific for Defence. Links to the other part of the recommendations can be found at the bottom of this page.

General Considerations 

The energy transition for defence needs to progress in several areas. Energy sources, energy carriers (i.e. fuels/storage), energy efficiency/savings, and smart energy applications and design. Naturally all of this must be clean and sustainable, or at least better than the ones they replace. The most effective climate impact policy by far is innovation and hence should be invested in the most. In particular when required the operational solutions are not available in the commercial market.

While maintaining the required operational effectiveness, a successful energy transition for defence needs to:

  • take into account short and long term solutions (i.e. 2030, 2050 and beyond)
  • invest in innovation because this offers the best return by far (up to 11 times better when compared to other climate policies)
  • drive technological downstream developments (improve efficiency, discover new methods)
  • promote fundamental and abundant energy availability (i.e. energy security)
  • develop non fossil powered weapon systems keeping energy autonomy, logistic compatibility  and quick deployability in mind.

We investigated along the following lines:

  • efficiency and energy conservation
  • role of hydrogen and synthetic e-fuels
  • application of small and medium scale nuclear energy technology u smart defence application, integration and design

Main Conclusions

Comparing climate impact policies, innovation offers by far the biggest return and hence should attract most investment and effort.

Small unmanned systems like UAVs, need less armour or space and life-support for crewmembersand thus less energy. These could complement or perhaps even replace larger traditional manned systems. Energy storage, either electrical in batteries, e-fuels, hydrogen tanks or another medium such as iron powder, needs to be made efficient, rugged, safe and reliable for military use. Modular design of flexible energy systems will enable swapping in/out new/old tech as it becomes available thus making it future proof.

Existing fossil technology needs to be improved through cleaner combustion technology (DFI[1]) and cleaner fuels (DWE[2], OME[3]). Retrofitting existing systems makes quick results possible. A hybrid combination of a methanol fuel-cell, a battery, and a methanol engine or generator, can result in an electric vehicle that has endurance and can be quickly charged or refilled. All the technology needed already exists but needs to be integrated. Ammonia can be a viable energy carrier for maritime application but some development is still needed.

The ultimate source of clean, reliable and dispatchable heat and electricity is nuclear. For militaryapplications the development of freight-container sized micro-reactors is of critical importance. The US is pursuing this and so should the EU.

Synthetic fuels can be produced by pairing nuclear reactors with chemical installations. Nuclearcan deliver the heat and electricity for the process itself but also to produce the feedstock needed. This needs to happen on both a small scale and large scale.

For many industrial processes high temperature heat is required which enables different processes and improves efficiency considerably. Therefore the development of high temperature molten salt or gas cooled nuclear reactors is essential in the long term. This technology has already been demonstrated in the 50’s in Germany and more recently in China on a substantial scale.


Below are some potential projects that should be supported by the European Commission. Additionally some recommendations are listed which will also support the energy transition for defence.

1. Short and intermediate term gains 

a. Apply modularity in design, especially so that energy-related platform elements can be replaced when better/cleaner alternatives become available (especially true for ships).

b. Expand and complement use of UAVs to complement regular (traditional) platforms. Many tasks could potentially be assisted by (or even taken over by) UAVs or comparable technology.

c. Complement and extend use of smaller, lighter and more agile unmanned systems that need not be heavily armoured as this saves fuel/energy.

d. High energy laser systems and rail-guns are essential to counter future (or even present) threats.Where they will save on regular ammunition and related logistics, suitable power sources for these systems need to be developed.

e. Invest in digitisation of general replacement parts such that they can be 3D printed on demand instead of stored and shipped, thus relieving logistical pressure and energy use.

f. Build small modular nuclear reactors (≈300 MWe) to supply electricity and heat to large military bases. These could be built on or near the bases and paired with industrial chemical plants producing fuels from sustainable feed-stock and supplying heat to the communities in the neighbourhood.

2. Longer term R&D

a. Energy storage,*) be it through storage of electricity in batteries or hydrogen in tanks (or another medium) needs to be made rugged, safe and reliable for military use;

b. Improving current fossil based systems*) reducing emission and improving efficiency, could be achieved by ducted fuel injections (DFI) and diesel/water-emulsion (DWE) technology. These could potentially be retrofitted on existing engines and thus have an immediate effect in the short term. Specially engineered oxymethylene ethers (OME) based fuels offer an extremely clean burning alternative to diesel, especially when these can be produced using clean and sustainable sources and feed-stocks;

c. Hybrid technology*) such as a combination of a methanol fuel cell, battery, and a methanol engine, could result in an electric vehicle that can be charged using clean sustainable electricity but also has endurance due to the methanol fuel cell and combustion engine;

d. Methanol and ammonia**) are potentially clean fuels if produced sustainably. The use of ammonia is especially suited for maritime applications but needs to be developed further (i.e. technology and supply chain);

e. Micro nuclear reactors**) will be a reliable source of clean sustainable power that can supply heat and electricity independently and for prolonged periods when other sources cannot fill the gap. Europe will need its own micro reactor specifically designed for military use, i.e rugged, trans-portable, low maintenance, etc;

f. Sustainable synthetic fuels[4]**) are intended to replace traditional fossil fuels as a drop in replacement. These need to be produced at a substantial scale using sustainable energy sources and feed-stocks. Efficient large scale production can best be achieved using a small modular nuclear reactor (SMR) paired with industrial scale chemical plants. Small scale containerised versions of these power-liquid installations, paired with micro nuclear power plants (XSMR), could provide an independent onsite fuel supply during operations;

g. Advanced high temperature reactors,***) be it molten salt or gas cooled, will enable a substantial jump in efficiency and unlock processes that rely on, or profit from, high temperatures (e.g. hydrogen production). These designs are also interesting from a safety perspective due to low pressure operation.

Read or download all documents of the policy proposal here
[1] Ducted Fuel Injection, [2] Diesel Water Emulsion, [3] Polyoxymethylene dimethyl ether, [4] Including e-fuels
Picture: E-Fennek - NL MoD Sargeant-major Cristian Schrik