Greening Defence: The British Army’s Bet on Electrification

Main Image Credit A performance test of a Jackal vehicle fitted with an electrical hybrid system. Courtesy of Defence Imagery / OGL v3.0

The latest Greening Defence commentary examines how the Army has placed a bet on technology and, through the electrification of the operational fleet, intends to improve capabilities while concurrently reducing carbon emissions.

The current Chief of the General Staff noted as part of his keynote speech at the 2019 DSEI that climate change will have a ‘profound impact’ on how the Army operates in the future. This refers predominantly to the consumption of military fuel. While aviation fuel accounts for much of the 666 million litres of fuel used by the Ministry of Defence (MoD) between 2018–19, a UK Army division can consume approximately 800,000 litres of diesel per day during high-intensity warfighting – the equivalent energy output of a medium-sized nuclear reactor. Although MoD emissions decreased by 26% between 2015/16 and 2018/19, fuel consumption emissions only dropped by 9%. The Army hopes to resolve this issue largely through the electrification of the operational fleet.

I think we may be at that inflection point in how we power our next generation of vehicles  

General Sir Mark Carleton-Smith, 2019

However, electrification for the Army will not be easy. Both the public and politicians have called for an eco-friendlier military, but conversations often do not acknowledge the potential impact of change on capabilities. Among the challenges will be overcoming heavy reliance on the commercial sector to develop suitable technology, limited financial resources, and the complexity of retrofitting an existing vehicle fleet.

Electrification: The Story So Far

As Brigadier Matthew Cansdale, Head of Future Force Development, notes, ‘electrification is a win-win for the Army as it enables operational advantage, reduces logistic demand, and puts the Army on the path to meeting Net Zero 2050 sustainability objectives’. Under Project MERCURY, the Army aims to incorporate electrification into the future fleet and facilitate further developments across a broader scope; it has set three milestones to tackle the transition process.

By 2025, the Army will complete experiments with Hybrid Electric Drive (HED) prototype vehicles. Promisingly, this process has already begun with testing on hybrid technology retrofitted to a MAN SV truck, FOXHOUND and JACKAL vehicles following a £9 million investment. The initial results from the Technology Demonstrator 6 are largely positive, with internal trials reporting improved cross-country performance, easier handling due to instant torque, greater steering precision and training times reduced by 30%; wheeled platforms can now conduct neutral turns akin to their tracked equivalents. Power generation from these platforms is equally promising. A single MAN SV can produce 500 kW of power, the equivalent of nine generators, meaning two-and-a-half MAN SV trucks can power an entire Role 3 hospital. Further experimentation is ongoing to understand the operational benefits of greater range, silent running and reduced thermal signature, particularly in terms of increased survivability. These positive results look set to inform an electrification plan for operational platforms beyond 2025.

By 2030, the second phase of works will see the military deploying HED-equipped troops on operations at sub-unit and battlegroup level, the introduction of deployable micro-grids to replace separate generators, and HED charging of Unmanned Air Systems and Unmanned Ground Vehicles. Finally, by 2035, the aspiration is for most land capabilities to be hybrid or fully electric.

Defence will need to retain flexibility to avoid irreversible longer-term procurement decisions that might lock it into investments in polluting equipment or close off future opportunities to improve sustainability

By focusing on the operational advantages of electrification rather than a moral responsibility to the environment, the Army has the potential to reap the rewards of reduced carbon emissions through the creation of a low-carbon force which can operate in theatres affected by climate change. While this reality may have been a fortunate side-effect of the current response, it is a useful lesson. When dealing with environmental responsibilities, appealing to people’s moral conscience is unlikely to gain widescale buy-in or financial backing; the use of physical rewards such as improved capability or financial savings will incentivise budget-holders to support change. This should be the driver for pushing electrification forward beyond early experimentation.

The Challenges

The main issue for Defence will be when, or whether, to go fully electric. At present, much of the future Equipment Plan will run off conventional combustion engines until at least 2050, with no option to electrify. Fully electric large platforms, particularly tracked, are unlikely to be practical by 2035 without a substantial breakthrough in battery capability. The Chief of the General Staff admits that ‘we’re industrially still some way away from completely living without carbon engines in our principal war-fighting equipment’. Therefore, the Army will be forced to retrofit existing platforms where possible as a stop-gap solution, adopting a hybrid approach. This will require a careful cost- benefit assessment in recognition of the fact that it may only be feasible for smaller, lighter vehicles. The military may have to temper its eco-aspirations in the short term.

Additionally, there is nothing to prove that electrification is the definitive answer; there is no equivalent alternative to diesel at present. The incredible energy density of hydrocarbons is what has powered the 20th century, and is why 90% of the world’s transportation remains dependent on oil. Some environmentalists have made the case for hydrogen, although difficulties regarding energy per unit volume, and the cost of complex cryogenics to maintain -235 degree storage, are significant factors as to why it has not progressed. Research by the National Defense University concluded that hydrogen compressed to 5000 psi lacks the required energy density by volume to be an effective replacement for fossil fuels in the Department of Defense; without a technological breakthrough, the case against hydrogen appears compelling.

However, if electrification is the answer, it requires appropriate long-term prioritisation. A networked, ‘just do it’ approach – as opposed to the more traditional military hierarchy – will certainly cut through unnecessary red tape, and is already creating space for uninhibited innovation. Yet the environment has not been sufficiently prioritised or financed across the British Army, meaning many of the environmental benefits are secondary by-products. There is a danger that electrification could simply become a Key User Requirement to be ranked against performance capabilities; in this instance, the environment could be quickly de-prioritised. Compromise in capability development is therefore likely to be a necessity for future equipment programmes.


Electrification could provide an opportunity to transition earlier to greater use of Robotic Autonomous Systems; these offer instantly viable options for electrification now, given their relative size, weight and power requirements. When looking for larger, crewed options, the tactical wheeled vehicle fleet can make use of a commonality with existing commercial platforms where solutions are either already available or can be quickly developed. For example, GM Defense, a US branch of GM, was able to convert an Infantry Squad Vehicle to electric power inside 12 weeks using 90% commercial off-the-shelf components. Whatever the decision, Defence will need to retain flexibility to avoid irreversible longer-term procurement decisions that might lock it into investments in polluting equipment or close off future opportunities to improve sustainability as green technology matures.

Making the moral argument is not enough; leaders need to recognise the potential impact of climate change upon capability, the financial implications of inaction and the substantial risk to reputation

A constraining factor for Defence will be its over-reliance on industry. With finite R&D funds, much of the automotive industry has opted to invest in battery technology over hydrogen fuel cells. With many giants of the automotive world planning to cease production of fossil fuel-burning vehicles by 2030, and major energy suppliers already diversifying away from fossil fuels, the military will be forced to adapt. With even less R&D funding, Defence must – as a fast-follower of industry – follow industry’s lead; the Army simply does not have the resources to strike out alone. A whole-force approach may be required to allow industry to militarise commercial offerings and meet the needs of Defence.

The creation of a ‘Sustainable Technology and Implications for Land Capability’ Industry Advisory Group, including members of the military, academia and industry, will facilitate co-operation and appears to be a good starting point. Their recommendations will require financial backing and an element of flexible contracting to support the rapid exploitation of emerging technologies as they mature. Investment will also be required into the threat of cyber attacks and EMC on future power systems to de-risk electrification and ensure its green benefits are future-proofed. Finally, the defence industry should be incentivised by ‘green’ supply chains, reducing greenhouse gas emissions throughout manufacturing cycles and transportation. These factors require an end-to-end, whole-lifecycle approach to capabilities, with service plans which do not restrict the Army to the use of outdated technologies within a platform’s period of use.

To conclude, making the moral argument is not enough; leaders need to recognise the potential impact of climate change upon capability, the financial implications of inaction and the substantial risk to reputation. The British Army’s current approach is driven less by environmental requirements and more by a desire to enhance operational capability; the two should be seen as mutually beneficial. There will be a significant reliance on technological evolution to make electrification more efficient and thus more viable; this is the British Army’s ‘bet on tech’. Although difficult in terms of timing, the decision to transform now stands the Army in good stead to continue championing electrification on a global scale. Greater integration with international partners will expand the intellectual pool and increase innovation.

The views expressed in this Commentary are the author’s, and do not represent those of RUSI or any other institution.

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Lieutenant Colonel Alistair Beard

Former Army Visiting Fellow

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Dr Sarah Ashbridge

Research Fellow

Military Sciences

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