Energy Shields are power-fed personal force fields.
The first rudimentary energy shield was patented in 1997 by Alonso Melethat, and depended solely on a main power connection. The first versions were used for stationary objects — jewelry cases, government security terminals, network rooms, etc. — against explosive attacks. A personal vest-like version appeared in 2010, requiring the wearer to plug into a stationary power source.
Prtable energy vests came with the development of power cells and extended-life battery packs.