Solving power generation and power storage issues

By Paolo Valpolini

Depending on their dimensions and the situation military camps deployed in theatre can last for years. The number of antennas shows the need for a reliable power supply to guarantee vital communications. © P. Valpolini

The war in Ukraine shows well how much energy is important for our life. The same applies to the military world, both in country as well as when troops are deployed in operational theatres.

Issues at stake are somewhat different.

Environmental issues are usually at the forefront when considering military facilities in country, the military giving its contribution to the “green” posture by reducing energy consumption and improving the “cleanness” of power generation. However what is doable in a static environment cannot always be transferred when troops are deployed in camps created ad-hoc, which can vary in terms of dimensions and duration, ranging from MOBs (Main Operating Bases), often hosting runways and containerised infrastructures, and remaining in place for the whole duration of an operation that usually lasts years, to FOBs (Forward Operating Bases), smaller and being used for more limited periods of time, to COPs, (Combat Out Posts), team- or platoon-level, which are build for much more limited periods.

Forward Operating Bases can be relatively small, but nonetheless energy availability is key to maintain operational capability as well as a decent living standard. © P. Valpolini

In Mali the French Army refuelling system was put under stress due to long distances travelled by operational units, which added to the consumption at base camps. © French Army

The issues here can be different from those considered “in house”. While avoiding pollution remains a key issue, other elements acquire a higher priority; as an example reducing consumption is key in reducing the logistic footprint, should it be the amount of fuel needed for power generators, the volume occupied by batteries, that of fuel cells, or that of solar panels. Some solutions can find use in some situations, such as main operating bases that tend to cover considerable surfaces and remain operational for a long time, months but more often years, while forward operating bases are smaller and might remain operational for shorter times, not to mention combat outposts. Reducing the logistic footprint can have considerable effects also on operational capabilities; thinking about fuel resupply, reducing and optimising energy consumption means reducing the number of convoys which in turn reduces risks and increases the availability of combat forces, that instead of escorting convoys would be able to operate in other roles. Reducing consumption goes beyond the optimisation of energy use in camps; the mission in Mali put under stress the French fuel resupply chain, leading the French MoD to consider fuel consumption reduction issues, one of them being the adoption of hybrid propulsion, which promises to use less fuel compared to current vehicles, with other benefits that we will analyse later.

In the mid-2010s a US study1 demonstrated that using commercial off-theshelf technologies of that time it was possible to obtain considerable energy savings. The system included

1- Smart and Green Energy (SAGE) for Base Camps Final Report, M Engels, PA Boyd, TM Koehler, S Goel, DR Sisk, D Hatley, V Mendon, J Hail – US Department of Energy January 2014.

a smart microgrid with a common control system coupling multiple diesel generators, a batterybased energy storage system, a solar hot water system providing preheated water to fuel-fired water heaters, and two solar electric photovoltaic arrays, while troop housing was fitted with improved insulation. The experiment results demonstrated that adopting all the proposed solutions could bring to a 54% fuel saving, while a reduced solution that included the microgrid and renewable energy systems could bring to a 41% saving. It also highlighted that savings were higher on smaller camps, as bigger ones were already adopting more efficient systems.

NATO is closely considering logistic improvements, and in 2013, 2015 and 2019 three exercises named “Capable Logistician” were played, all focused on smart energy issues. One of the issues identified was the lack of energy monitoring and data collection schemes, and that of interconnectivity between energy components. According to NATO sources the smart grid put into place by US and Italian troops, which connected hybrid power sources and which software allowed powering up diesel generators only when needed, allowed a 90% fuel consumption reduction compared to standard 24/7 diesel generators operations. This was measured using a Canadian universal energy-monitoring tool.

To deal with the energy issue, 10 years ago, in July 2012, the Atlantic Alliance created the NATO Energy Security Centre of Excellence, ENSEC COE in short, which aim is to provide qualified and appropriate expert advice on questions related to operational energy security. Beside looking at immediate or short-term issues, the ENSEC COE is in charge of identifying future needs in NATO transformation activities, with the aim of preventing or mitigating emergent challenges on military operations due to the global scarcity of energy resources and the complexity of the international energy system. In 2021 the ENSEC COE issued a report titled “Energy efficiency and renewable energy solutions in NATO and Partnership for Peace countries’ military operations” 2 that provides a thorough analysis of solutions adopted in Estonia, Finland, France, Georgia, Germany, Greece, Italy, Latvia, Lithuania, Norway, Poland, Sweden and the United States of America.

The Dutch Army deployed a sustainable power system in Mali, where its troops were part of operation MINUSMA (Mission multidimensionnelle intégrée des Nations Unies pour la Stabilisation au Mali, United Nations Multidimensional Integrated Stabilization Mission in Mali). Operating in West Africa gives good guarantees in terms of sunshine, the Deployable Power Module by EST-Floattech heavily relied therefore on thin film solar panels provided by Dutch Zonel Energy Systems installed on roofs, which were the main energy source for loading Green Orca 1050 lithium polymer batteries. Twenty-six of those were packed together, with

A Canadian civil engineer prepares a micro-grid system to be installed at the wind power station as part of NATO Smart Energy Training and Assessment Camp at Ziemzko Airfield in Poland during “Capable Logistician 2019” exercise. © NATO

2- Energy Highlights by Ana Gogoreliani co-aothored by Fabio Indeo and Teimuraz Puluzashvili, July 2021, https://enseccoe. org/data/public/uploads/2021/09/nato-ensec-coe-energy-efficiency-and-renewable-energy-solutions-in-nato-and-pfpcountries-military-operations-study-report-2021.pdf.

French Air Force personnel unfold photovoltaic solar panels connected to a “green to grid” portable trailer at the Smart Energy Training and Assessment Camp in Poland during “Capable Logistician 2019” exercise. © NATO

In Mali the Dutch Army used the Deployable Power Module, developed by EST-Floattech with solar panels provided by Zonel Energy Systems. It allowed considerable fuel consumption and maintenance costs reduction. © EST-Floattech

two strings of 13 batteries connected in a serial setup, the two strings then connected in parallel, a 250kW generator ensuring reloading when solar power was not available. The battery management system (BMS), developed by the same EST-Floattech, ensures that each single cell, each battery (made of 14 Li-Po cells serial connected) and each package of batteries is actively balanced in real time, monitoring the single cell voltage, current, state of charge, state of health and state of discharge. The Deployable Power Module reduced the amount of energy produced by generators compared to conventional setups, allowing the latter to function mostly at night therefore at lower temperatures ensuring higher yield, and powering on generators in order to allow them to run at 85% of their power in the most effective mode. Among benefits, it reduced fuel consumption, maintenance costs, and ensured a very steady micro grid.

Axsol of Germany is a company specialised in designing, developing and producing partially and completely self-sufficient energy storage systems for mobile as well as semi- and fully stationary use. After having successfully won the first three rounds of the “Pop Up City” contest organised by the Canadian Department

Axsol Energy Container Solutions come in different size and capacity and are employed both by civilian and military users. © Axsol

of National Defense the team including Axsol, which is responsible foe energy in cooperation with Pop Up City Inc., is competing in the fourth and final round. Four core technologies are involved beside energy that are dealt with by other team members: shelter, black water, grey water. The full energy system includes battery storage, photovoltaic array and diesel generators for back-up generation, as well as energy recovery from waste treatment. The following table shows fuel savings per year in volume and cost (assuming a cost per litre of diesel fuel at 80 € on site). The consortium of which Axsol is part ranked first in the Pop Up City contest and is currently building a prototype camp at Canadian Forces Base Gagetown, New Brunswick, which will be completed in October 2022 and will allow demonstrating the savings obtained in simulations.

AXSOL is providing the integrated hybridized energy supply from battery storage (1.5 MWh), photovoltaic system (750 kWp) and diesel generators (2 x 125 kW), an adapted control and life cycle concept.

Axsol ECS (Energy Container Solution) products couple batteries and diesel generators with other power sources, sun- and wind-based. ECS integrates from 70 to 3,000 kWh of battery storage in 10-, 20-, or 40-foot ISO containers, the larger one ensuring two-day autonomy to a 150 men camp relying only on batteries. Another product aimed at semi-or full-stationary camps is the CN20 hybrid, which combines Axsol intelligent power generation and storage system with an innovative, foldable 20-foot container developed by Continest of Hungary providing the customer with a self-contained energyautonomous solution fitted with battery, photo voltaic and back-up generator. The concept was tested during “Brave Warrior” organised by the Hungarian Defence Forces in September 2020

Components Per person Per 150 Per 1,500

Battery 10 kWh

Photo voltaic power 5 kWp

Photo voltaic area 26.5 m2 1.5 MWh 15 MWh

750 kWp 7.5 Mwp

4,000 m2 (63 x 63 m) 40,000 m2 (200x200 m)

Diesel generator 1.5 kW

Savings Diesel 850 l +

Cost Savings 68,000 € 270 kW 2.7 MW

127,500 l + 1,275,000 l+

10.2 million € 102 million €

A cutout of an Axsol ECS container. Batteries ensuring adequate energy storage occupy the greatest part of the volume. © Axsol

in the Bakony hills, and following that event Hungarian forces started receiving their first containers.

Until now the company relied on LiFePO4 (lithium iron phosphate) batteries. A spin-off from Axsol, So-Cer AG, based in Würzburg, has partnered with Fraunhofer-Institut für Keramische Technologien und Systeme to develop a SodiumCeramics battery system based on a wholly new chemistry that uses common materials such as water, salt, nickel and alumina, which allows to recycle it very easily. According to the company its characteristics remain optimal even in extreme cold and hot conditions, it lasts thousands of cycles, and it can be switched off for years without any negative effect. It is easy to transport as it doesn’t burn or explode. Superior in all aspects compared to current solutions, the So-Cer battery will have a marginally lower power density, 140-150 Wh/kg, compared to the 90-160 Wh/kg of current LiFePO4 batteries. An interesting characteristic is that current and voltage depend on the cell height and diameter, which allows developing cells for various uses. Moreover So-Cer batteries allow creating plantbuffering systems up to TWh-level. The new battery type should become available from 2024 onwards and according to So-Cer estimates, when produced at scale its price should be less than 100 €/kWh. According to Axsol one of the first potential uses might be the aforementioned Canadian programme.

Teaming with SFC Energy, a German specialist in fuel cells, Axsol is capable to provide its products where fuel cells replace diesel generators to ensure continuity when photovoltaic panels do not operate in reloading batteries extending hybrid solutions to mobile use, such as COPs. At Milipol 2021 Axsol unveiled its Arvey B2 and SFC EFOY Pro 12000 Duo methanol fuel cell system.

Axsol teamed with Continest of Hungary to develop the CN20 hybrid, an energy autonomous container that includes batteries for energy storage, and photovoltaic and generator energy producing system. © Axsol

Axsol Arvey B2 coupled to SFC EFOY Pro 1200 Duo. This solution was presented at Milipol 2021 in Paris, and in around 100 kg can provide 2,400 W of power supply to a COP. © P. Valpolini

The Arvey B2 mobile power supply power is up to 2,300 W and its battery capacity is 2,250 Wh, stored in LiFePO4 battery. This can be charged by generator, power grid, photovoltaic (up to 900 W) or fuel cells, and retrieved through two 230 V AC sockets. Developed according to military standards the Arvey B2 is IP 54, weighs 49.7 kg and its dimensions are 564 × 534 × 259 mm. At Milipol Axsol and SFC Energy were exhibiting in two adjoining stands and in the middle we could find the combined solution, the EFOY Pro 12000 Duo being capable to provide 500 W in 24/48 V DC; the fuel cell system was shown with two M10 10 litres fuel cartridges, consumption in standard conditions being 0.9 l/ kWh. The fuel cell has a weight of 32 kg, to which we must add that of fuel cartridges, while its dimensions are 640 x 441 x 310 mm. SFC has a whole catalogue of solutions ranging from the Jenny series portable fuel cells for dismounted operations up to trailer based solutions including fuel cells and photovoltaic panels.

Besides working with partners, Axsol is looking at innovative solutions in energy generation. Thanks to its cooperation with Fraunhofer application-oriented research organization it gained access to a new groundbreaking Fuel Cell and Electrolysis technology. According to the company this will be the only fuel cell for diesel, the same stack technology allowing producing hydrogen and process it via FischerTropsch 3 to carbon neutral kerosene/diesel or other synthetic fuels. Solid Oxide Electrolysis

In cooperation with Fraunhofer IFKT Axsol is developing Sodium-Ceramic batteries. Here depicted a 100 Ah cell. These new batteries will be available from 2024 on. © So-Cer

Axsol Arvey B2 hosts a 2,400 Wh battery package and can be charged by power grid, diesel generators, solar power or fuel cells, and provide power to electronic devices, communication systems. © Axsol

3- The Fischer–Tropsch process is a collection of chemical reactions that converts a mixture of carbon monoxide and hydrogen or water gas into liquid hydrocarbons.

Oshkosh Defense developed the hybrid version of the JLTV, the eJLTV, which can export up to 115 kW, making it suitable to power up a COP. © Oshkosh Defense

The Scarabee, developed by Arquus, is one of the few hybrid vehicles already available, its launch on the market dating back to IDEX 2021. As all those vehicles it can provide power to external devices. © Arquus / N. Broquedis

(SOE) in combination with waste heat is claimed to be 30% more effective than any other current technology. Once the batteries in a camp are filled up, surplus renewable is used to generate hydrogen in the camp, which can be used to further process it to fuels of any kind. Axsol is promoting this technology to double energy efficiency on diesel and to produce diesel and kerosene on-site to reach maximum autonomy and higher safety. According to Axsol the diesel Fuel Cell will be available in 2024/25 while the electrolysis for military use will follow in 2028/29. This might lead Axsol to become independent in many aspects on alternative energy production and storage, considering also So-Cer batteries. Although no hybrid vehicles are yet into operational service, numerous prototypes are already running and a number of hybridisation programmes of existing vehicles have been launched. Diesel-electric hybrid propulsion is being considered for numerous reasons, giving advantages in operational and logistic areas, depending very much on mission profiles. One of the advantages of such vehicles is the high availability of electric power on board, due to the considerable amount of batteries.

In January 2022 Oshkosh Defense unveiled its eJLTV, the hybrid version of the Joint Light tactical vehicle. According to company data the eJLTV has a battery capacity of 30 kWh, with some growth capability. The lithium-ion battery pack can be recharged within 30 minutes keeping the diesel engine running, and beside the reduced fuel consumption (20%) and silent drive capability, the hybrid vehicle has an export power capacity of up to 115 kW. Considering a combat patrol with some vehicles in the hybrid version, this would mean that a COP could be powered by their batteries, eliminating the need for a towed generator. In March 2022 at the World Defense Show in Saudi Arabia John Cockerill Defense of Belgium unveiled its Cockerill i-X, currently powered by an internal combustion engine for trials, but destined to be

The All-Terrain electric Mission Module developed by Plasan of Israel is a one-axle module that can be coupled to other similar modules; electrically powered, it can be used to provide energy to a temporary base. © Plasan

fitted with a hybrid powerpack, this being part of the evolution roadmap. The French MoD is financing a hybrid prototype of the Griffon 6x6, which should be available by 2025. The key player is Arquus, the company having developed the VAB Electer in the past decade and being actively marketing its Scarabee 4x4, which was designed as a hybrid vehicle since inception. The same company is also developing the Mission Extender, an autonomous trailer that, being a fully electric system, can inherently provide electric power to a camp, should the need arise.

Plasan of Israel has fully developed the “trailer” concept with its ATeMM (All-Terrain electric Mission Module); a one axle electrically powered system, the ATeMM can be added to a conventional vehicle, providing add on mobility and electric power, one up to four modules can be lined together to form unmanned platforms of different dimensions carrying a variety of payloads, the single module having a battery capacity of 35 kWh can be obviously used to power a temporary camp.

While electricity demand is increasing due to the numerous power-hungry systems that are part of military equipment, on the other hand industry is active in finding solutions to reduce the logistic footprint and fuel consumption.

EDF: the INDY project

In late July 2022 the European Defence Fund issued the list of the approved projects that were submitted in 2021. Among those we find the INDY (Energy Independent and Efficient Deployable Military Camps). Related to the PESCO Energy Operational Function (EOF) project, it aims at developing a strategic roadmap towards future energy independent and efficient deployable military camps, based on a paradigm shift for energy production, conversion, storage, transport, distribution and final usage. The project is building on military and civilian EU and national projects. The INDY study project will last 24 months, EDF funding being worth € 14,229,475.59. The project is coordinated by TECES (Tehnološkicenter zaelektri nestroje), the Slovenian Research and Development Center of Electrical Machines and includes 19 more entitites: AVL List GmbH (Austria); CNV Consulting ad John Cockerill SA (Belgium); CAFA Tech OU (Estonia); Commissariat à l’Energie Atomique et aux Energies Alternatives, Ineo Defense and Nexeya France SAS (France), Fraunhofer-Gesellschaft and RheinmetallTechnical Publications GmbH (Germany); Intracom Defence S.A. (Greece); Leonardo S.p.A. (Italy); The Netherlands Organisationfor applied scientific research (Netherlands); Institutt for energi teknologi (Norway); Univerza v Mariboru, Univerza v Ljubljani and Kolektor sETup d.o.o (Slovenia); Equipos Móviles de Campaña ARPA SAU, Indra Sistemas SA and Instituto Nacional de Tecnica Aeroespacial Esteban Terradas (Spain).