Does the military use renewable energy? The US Department of Defense has already deployed hundreds of megawatts of renewable energy through public–private partnerships. But, thats about the extent of their capacity.
The start of the age of oil geopolitics is conventionally dated to 1911 when Winston Churchill converted the Royal Navy battleships to oil. Moreover, the main combat force of the superpower now relied on a new energy source.
How much did the world leave behind oil with this metric?
Just like in 1911, new low carbon energy sources made the first major impact in the naval domain. The 160 nuclear reactors of the US Navy displace substantial amounts of oil. Furthermore, a Nimitz class carrier would eat 5000 barrels/day. As a result, nuclear power unlocks previously inconceivable strategic options like sustained underwater operations.
However, Solar has started to make inroads to land warfare:
Communications, digital equipment and electronic warfare are electricity hungry, modular solar units in forward operations reduce the need for diesel generation with its vulnerable supply chain.
Does the military use renewable energy?
Small surveillance drones are increasingly electric. However, even for drones, the heavy combat ones like the Predator or the Turkish Bayraktar used successfully by Ukraine run on aviation gasoline.
Conventional kit that is still doing the heavy lifting is firmly in the age of oil:
An hour of combat operations for a battle tank is the equivalent of the oil use of 40 cars. In addition, a combat helicopter 150, a modern jet fighter around 400 without the afterburner.
An electric M1 Abrams tank with the current 10 minute refilling requirement would need a 60 MW charger (electric trucks are now experimenting with 1 MW, the ones deployed on the highways are between 0.05 and 0.35) and 10 football fields of solar panels supporting it.
In conclusion, the manufacturing of the special alloys and composite materials used in modern equipment is energy intensive and relies on hydrocarbons. Lastly, Churchill would still recognize the oil supply and logistics challenges of 21st century armies, oil supply security is national security.