Basics

Devices utilizing small fuel powered generators that produce electrical power of ~1-10 Watts
They utilize Micro Fuel Cells, Micro TECs, Micro Turbines, and Micro ICEs
They can power small conventional electronic devices such as smart phones and computers via a cable, or be integrated into speciality devices designed around Micropower Generators

Uses

The idea originated in the 80’s/90’s in NATO Countries along the development aims of the Single Fuel Standard
The idea was essentially to have Soldiers’ Radios, Jammers, GPS Navigators, or Batlefield Computers etc run on the same JP-5 / JP-8 as everything else
The idea could be made SLIGHTLY more “sane” by a larger worn device powering all the equipment on said person via a Wiring Harness of sorts combined into the Backpack Frame or Outerwear itself etc
- RE: Passive Exoskeleton and Active Exoskeleton especially
  - Although the advantage of this level of tech on a per-soldier level vs sticking them all in a (potentially cheaper) APC/IFV etc is debatable (despite the latter being far less “sci-fi” )
  - IE instead of Per-Soldier Bullet Direction Finding, Navigation, Comms, EW, and such…you just have that powered by the GIANT DIESEL TRUCK ENGINE…
The concept faded though with the proliferation of more energy efficient/smaller electronic devices, and the Lithium Ion Battery
- To a lesser extent reliable Alkaline Batteries and Disposable Lithium Batteries too

Several factors may make the pursuit of the technology worthwhile again, while at the same time making it more “workable”
1.) As per the Russian Invasion of Ukraine, short of expensive vehicles with MASSIVE Active Protection System + SHORAD investments (and things such as Net Protected Roads/Tunnel Networks, vehicles are vulnerable and Force Dispersion is a requirement
2.) Logistics are Strained
- Although Micropower wouldn’t be “pure” of this/Fuel Logistics still suffer
3.) UAVs, UGVs, Coms, and EW Requirements raise the need for Energy, while Battery Technology is advancing less explosively
4.) While the cost argument/tradeoffs vs PROPER mechanization still exist, the per-person loads, and COTS solutions, are making exoskeletons more viable
5.) Simpler options such as SOFCs exist that are far less “Kerbal” than Chip Scale Gas Turbines, or everyone having a Rotary Engine]] buzzing away on their backpack
- Also like batteries they are silent
  - For example consider Early Boston Dynamics to Modern (Battery Electric) Spot