The vast energy footprint of the United States military, the world’s largest institutional consumer of petroleum and a significant emitter of greenhouse gases, presents a unique opportunity: reallocating a fraction of its immense budget could fulfill the energy needs of a small country. Recent research indicates a substantial, asymmetrical relationship between military expenditure and energy consumption, suggesting that reductions in spending have a disproportionately larger impact on decreasing energy use than increases have on raising it.
The Scale of US Military Energy Consumption
The U.S. Department of Defense (DoD) is the single largest consumer of energy in the U.S. federal government, accounting for approximately 78% of all federal energy usage. In 2007, it was responsible for 93% of all U.S. government fuel consumption. Historically, the DoD’s energy consumption has been immense; in FY 2006, it used nearly 30,000 gigawatt-hours (GWH) of electricity, an amount sufficient to power over 2.3 million average American homes. If the DoD were a country, its electricity consumption alone would rank it 58th in the world, comparable to nations like Denmark or Syria at the time.
A significant portion of this energy, around 70%, is operational energy, primarily jet fuel for aircraft, which accounts for the largest share of the Air Force’s energy expenditures. In 2017, the U.S. military purchased approximately 269,230 barrels of oil per day, equating to about 100 million barrels for the year. The Air Force and Navy are the largest purchasers of fuel within the military.
The Environmental Impact
Beyond its sheer volume, the U.S. military’s energy consumption translates into a substantial carbon footprint. Between 2010 and 2019, the U.S. Department of Defense generated over 636 million metric tons of CO2 equivalent (Scope 1 and 2 emissions). This figure, if the U.S. military were a country, would place it as the 47th largest emitter globally, surpassing nations such as Sweden and Portugal. The environmental damage extends beyond carbon emissions, impacting air quality, ecosystems, biodiversity, and local populations around bases due to activities like burn pits and the use of hazardous materials.
The Potential for Energy Savings
A study published in PLOS Climate on July 2, 2025, demonstrated a strong link between U.S. military spending and the Department of Defense’s energy consumption and, by extension, greenhouse gas emissions. This research revealed that decreases in military expenditures have a greater effect on reducing energy consumption than increases in spending have on raising it.
The study’s forecasts project that sustained cuts to U.S. military expenditures could result in annual energy savings on par with the total energy consumption of a small nation like Slovenia or the U.S. state of Delaware by 2032. For instance, a continuous annual decrease in military spending at the 90th percentile (-6.59%) could reduce energy consumption from 640.62 trillion BTU in 2023 to 394.32 trillion BTU in 2032. These savings are primarily attributed to reductions in energy consumption from military facilities, vehicles, equipment, and particularly jet fuel. This suggests that reducing the scale of aviation operations could be crucial for significant emission reductions.
Beyond Cuts: Efficiency and Renewable Integration
The Department of Defense itself recognizes the importance of energy security and efficiency. The DoD’s Operational Energy Strategy aims to ensure access to sufficient and secure energy supplies for military capabilities, emphasizing demand reduction, diversification of energy sources, and improved supply chain resilience. Efforts include investing in more efficient combat systems, advanced energy management, and alternative energy technologies like in-situ energy generation and energy storage.
The Pentagon has been actively pursuing sustainable energy strategies for its installations, recognizing that energy availability is a national security issue. The DoD has invested in various energy-saving measures, including solar photovoltaic panels, heat-recovery heat pumps, and HVAC system recommissioning. The military is also exploring wind and solar power, fuel cells, waste-to-energy systems, and mobile microgrids that integrate renewable energy sources, aiming to reduce reliance on transported fuel. The DoD is committed to sourcing 25% of its energy from renewables by 2025, with the Air Force planning to use biofuels for half of its domestic aviation by 2016. These initiatives not only reduce energy costs but also enhance resilience and bolster military readiness.
Despite these ongoing efforts, the research highlights the significant additional energy savings that could be achieved through direct reductions in military spending. Reallocating a portion of the defense budget could not only lead to substantial decreases in energy consumption and greenhouse gas emissions but also free up resources for other critical areas like climate change mitigation and adaptation.
