Reduce impact of defence on climate change
Defence emissions come from all areas of defence, and some areas do create significantly larger emissions than others (for example in military aviation).
Defence emissions come from all areas of defence, and some areas do create significantly larger emissions than others (for example in military aviation).
Defence’s total reported greenhouse gas emissions footprint between April 2022 and 2023 was 3.1 million tonnes of carbon dioxide (CO2) equivalent. This is a standardised measure of how different greenhouse gases contribute to global warming compared to CO2. Defence’s emissions made up 50% of UK central government CO2 emissions and 1% of total UK emissions.
The image here shows the proportion of UK defence CO2 emissions (1 square represents 1% of total emissions).
There are 3 types of defence greenhouse gas emissions, relating to the level of control defence has over them:
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Direct greenhouse gas emissions made by defence. For example, fossil fuels used to heat buildings, drive vehicles or operate military capability.
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Indirect greenhouse gas emissions from the generation of energy purchased by defence. For example, electricity bought from a national supplier.
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Indirect greenhouse gas emissions from activities across the organisation. For example purchased goods and services, business travel, employee commuting and waste.
Defence can fully exploit opportunities to reduce type 1 emissions but must work with others to influence type 2 and 3 emissions. For instance, the hybridisation or electrification of many capabilities will reduce type 1 emissions, but defence must also consider how the electricity is produced, stored and transported (all type 2 emissions).
UK defence actions and choices are critical to UK greening government commitments on emission reduction being successful and also helping the UK government achieve its legal commitments to be net zero by 2050.
UK defence aims to reach the least possible greenhouse gas emissions from its operational capability, only using fossil fuels where unavoidable. However, environmental sustainability cannot compromise operational effectiveness. This requires an understanding of defence’s current and future energy demands.
Defence requires energy both to support operations and for business as usual. This includes for infrastructure, vehicles and equipment in the UK and overseas, some of which will be operating in dangerous, austere or extreme environments.
Defence can lower its emissions of greenhouse gases through the replacement of fossil fuels with alternative energy sources. Although not all areas can move to alternative fuels in the short term (especially bespoke military vehicles), fossil-fueled capabilities with a long in-service lifespan risk becoming ‘stranded assets’. This includes capabilities which are expensive to fuel, difficult to maintain and unaffordable.
The future energy market predicts a move in both the civilian and defence sectors towards alternative energy sources. The individual choice of alternative energy (especially fuels) will depend on many factors. These factors include security of supply and having the infrastructure in place to support supply (storing, refuelling and recharging).
Aviation forms a high proportion of defence’s fuel consumption. The Royal Air Force (RAF) work in collaboration with UK industry to lead on defence development and the use of both synthetic and sustainable aviation fuels. Many aircraft could get at least 50% of their energy from sustainable aviation fuel sources in the future. This depends on cost and availability, but would significantly reduce harmful emissions.
In the maritime environment, commercial shipping is considering the use of any of the following as fuel for ships:
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ammonia
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biodiesel
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methanol
Commercial ships often move from point to point along scheduled routes, but naval ships need more flexibility. This requires adaptable supply, as well as engines and fuel storage that are (potentially) fuel flexible - if this becomes more workable in the future.
Land based vehicles can run on electricity, but current battery energy density limits their range compared to liquid fossil fuels. Electric vehicles already offer a realistic alternative for the non-tactical (or ‘white’) fleet, but they’re currently less likely for most combat or specialist vehicles. Hybrids may offer some benefit for these vehicles though.
Proven technologies could generate electricity for infrastructure on the defence estate and within deployed bases. These could include solar panels and wind turbines, plus nuclear micro-reactors.
This will not only cut down emissions of greenhouse gases, but provide other benefits too. For instance, it could support the move for operations to be more self-sustaining. And reducing the deployed logistics demand for fuel resupply convoys lowers the ‘tooth to tail’ ratio and reduces the risk to life.
By using diverse renewable and non-renewable energy production sources, and creating micro grids that combine localised generation and storage, we can increase resilience. Using multiple fuel sources could also increase resilience and allow use of fuels of opportunity but limited availability, such as waste fats and oils. But this will likely complicate support and logistic demands.
Examples of greener platforms and vehicles
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The RAF set a Guinness World Record with the first flight using 100% synthetic fuel in an unmodified light aircraft without affecting performance.
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RAF Voyager strategic air transport flight demonstrated the military viability of 100% alternative aviation fuels made from waste-based sustainable feedstocks (such as used cooking oil).
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The Army have tested hybrid technology retrofitted to MAN SV, Foxhound and Jackal vehicles, providing energy efficiency and tactical benefits (including silent running, lower thermal profile and ability to power additional battlefield systems).
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Offshore Patrol vessels HMS Tamar and HMS Spey have selective catalytic reduction systems to reduce nitrous oxide emissions by up to 97%.
Examples of alternative energy generation
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Blocks in the Ministry of Defence’s Nesscliff Training Area have air source pumps and generate electricity from solar panels installed on the roof (part of their Net Carbon Accommodation Programme).
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Portsmouth Naval Base has increased use of electric vehicles and installed wind turbines. Its Queen Elizabeth class Logistics Centre has over 750 solar panels.
Examples of alternative technologies
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Nuclear micro-reactors: a truck portable nuclear reactor that can generate up to 20 megawatts of thermal energy to generate electricity. These could be used at deployed military bases to provide a dense power source.
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Microgrid: a self-sufficient energy system that serves a discrete geographic footprint, containing one or more kinds of distributed energy (solar panels, wind turbines and potential small nuclear reactors) that produce its power. It can also contain energy storage, and charging points.
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The RAF set a Guinness World Record with the first flight using 100% synthetic fuel in an unmodified light aircraft without affecting performance.
-
RAF Voyager strategic air transport flight demonstrated the military viability of 100% alternative aviation fuels made from waste-based sustainable feedstocks (such as used cooking oil).
-
The Army have tested hybrid technology retrofitted to MAN SV, Foxhound and Jackal vehicles, providing energy efficiency and tactical benefits (including silent running, lower thermal profile and ability to power additional battlefield systems).
-
Offshore Patrol vessels HMS Tamar and HMS Spey have selective catalytic reduction systems to reduce nitrous oxide emissions by up to 97%.
-
Blocks in the Ministry of Defence’s Nesscliff Training Area have air source pumps and generate electricity from solar panels installed on the roof (part of their Net Carbon Accommodation Programme).
-
Portsmouth Naval Base has increased use of electric vehicles and installed wind turbines. Its Queen Elizabeth class Logistics Centre has over 750 solar panels.
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Nuclear micro-reactors: a truck portable nuclear reactor that can generate up to 20 megawatts of thermal energy to generate electricity. These could be used at deployed military bases to provide a dense power source.
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Microgrid: a self-sufficient energy system that serves a discrete geographic footprint, containing one or more kinds of distributed energy (solar panels, wind turbines and potential small nuclear reactors) that produce its power. It can also contain energy storage, and charging points.
Demand for energy within defence increases as the use of technology that underpins western defence increases. This will lead to a rising need for energy efficiency across defence and on military operations, and so we will have to refine how we use energy to avoid wastage.
Energy efficiency will reduce:
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cost
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the need for dismounted soldiers and tactical vehicles to carry ever-larger batteries
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the frequency of fuel and supply convoys that risk lives and consume military resources
It will also enhance capabilities by enabling longer operating ranges.
Increase equipment efficiency
Ways to increase efficiency of equipment:
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improve fuel efficiency of power sources
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ensure equipment operates optimally
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reduce consumable burden of equipment to reduce frequency of supply
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change physical design (for example, reducing weight or drag)
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consider energy efficiency when matching the right equipment to the job
Modelling and simulation offer opportunities to improve efficiency of platforms including using digital twins to aid design and to assess performance in a broad range of different scenarios to identify how to reduce fuel usage.
Increase infrastructure efficiency
People work, train and live on the defence estate. And so if we enhance the efficiency of infrastructure and promote behavioural change, it will have a large impact. Some of the highest energy consumers within defence infrastructure are:
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heating
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air conditioning
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refrigeration
Simple changes such as the replacement of traditional lighting systems by LEDs, can make a big difference. This reduces energy usage and lowers heat emissions, which reduces the need for air conditioning. If we also increase insulation we can reduce the loss of energy from buildings. More radical changes present new opportunities. For example, the potential to reuse waste heat from equipment to heat buildings or provide power.
Understanding energy requirements and consumption will inform optimisation and reduction of energy usage. The use of artificial intelligence (AI) could improve this further and enable control and monitoring of heating and cooling systems to adjust to outside conditions.
Change behaviours
Developing a new culture and helping people make more informed choices is crucial to saving energy . Simply put, if you turn off a light switch, or walk rather than drive, the effects accrued are by no means small. The goal is still to reduce GHG emissions
Alternative ways of working
Reducing travel for work can go a long way too. It could be possible to attend meetings, exercises or training virtually instead of in person - immersive technologies can carry out exercises and training. Synthetic environments (SE), augmented reality and mixed reality are all immersive technologies which have the following benefits:
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reduce travel required to and from exercises and training
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reduce use of operational vehicles during training
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provide reproducible training opportunities
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allow greater opportunity for experimentation with international partners
These technologies offer an alternative rather than a replacement for live training. There’s still a need for first-hand experience and a need to demonstrate our capability to others. This will reduce the energy burden over live training, but simulated environments come with their own energy burden.
Using autonomous vehicles across land, air and maritime environments, instead of manned vehicles, will help lower carbon emissions through reduced size and weight.
The circular economy can help too with self-sustainment. The idea is that maximum value is extracted from resources with minimum waste generated for disposal. In order to keep this system going, we need to:
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reuse or repurpose items
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increase the robustness and lifespan of equipment
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increase the ability to repair on site
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fabricate parts using advanced manufacturing mechanisms (3D printing)
Examples of energy efficiency
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the Net Carbon Accommodation Programme (NetCAP) buildings are equipped with smart building technology which uses interconnected automated technologies to control the building’s operations (this enhances the efficiency, operability, safety, and comfort of the building)
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antifouling paint applied to Type 26 frigates limit marine growth and together with the hydrodynamic redesign will ensure engine efficiency
AI, machine learning and data science
AI, machine learning and data science are a family of related technologies that exploit:
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computer processing
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algorithm development
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data availability, gathering and storage
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electronic connectivity
Read one of our other biscuit books for more detailed information on AI.
Climate-relevant applications in defence
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optimising performance through the real-time monitoring of data about people, equipment and the environments they’re operating in to predict problems and target appropriate interventions (such as repairs, rest, or training)
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protecting our people from harm by automating tasks in hostile environments
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extending the life of equipment and consumables, and reducing holdings, logistic burden and waste through predictive maintenance, improved stock management and resupply
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managing buildings and facilities to optimise energy management and reduce CO2 emissions
Remove
Carbon sequestration is the removal and storage of CO2 from the earth’s atmosphere. It can happen in any of the following ways:
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biological sequestration: where carbon dioxide is stored in the natural environment (this includes ‘carbon sinks’, such as forests, grasslands, soil, oceans and peat or wetlands)
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geological sequestration: when carbon is stored in places such as underground geological formations or rocks
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technology or industrial options (including direct air capture and pre and post production capture)
As UK defence owns 1% of the UK landmass, it could use rural management practices to restore, enhance or develop natural and long-term biological carbon sinks. This can enrich biodiversity and military utility (by providing a wider range of training environments). But it can also make some land less productive or viable for armoured warfare training.