ELECTRIC
Seems like the the Smallest of mixers are Elecrical Powered and so are some of the largest ones at the Batch Plant Level are Electric motor driven also. Most that fall in between are Gasoline or Diesel powered.
Small Electric Mixers
Quiet Operation: Ideal for residential or noise-sensitive areas, or Indoors.
Zero Emissions
Low Maintenance
Fewer Parts and no Fuel System.
Easy to Transport and Store.
Disadvantages for smaller Portable models.
Plugged into an Extension Cord when in use. Wet Location by nature of the work: May Trip GFCI.
Less Powerful than Gasoline or Diesel: Generally suited for lighter workloads.