According to StartPac, airfields have a great deal of power requirements that aren’t very easy to solve. Planes will disembark and takeoff from nearly every hangar and air strip several times a day. While those planes are prepping for takeoff, they need to be powered, cleaned, and re-fueled. Running that kind of infrastructure is both expensive and extremely difficult to do in a coordinated manner.
One of the saving graces for commercial airfields is the innovation of portable power. Rechargeable batteries aren’t a new concept, but being able to produce them at a small enough scale, with a high enough output, is.
A turbine starting engine needs to have its blades spun before energy can be generated by and for the engine. It requires some kind of external power in order to accomplish this task. In the olden days, and even with some private planes, pilots and ground crew might simply spin the rotors until the engine cranks on.
Larger commercial jets have extremely powerful gas turbine start up engines that would be dangerous to hand crank. In commercial air fields, an external power source forces air through the turbine, which gets the blade spinning.
Now imagine doing that to a helicopter, which lands on a raised portion of concrete in many cases. It takes a hand rolled or self propelled power unit to get the battery in place. Fuel trucks need longer hoses to maneuver into place too.
Power distribution on the airfield is important, and mobility is a crucial component of that distribution.