The electrical potential (Voltage) between the ground and the atmosphere above: "...ground‐level electric fields ranged from 3.2 to 7.6 kV per meter."
For all the gory details go here:>>
http://onlinelibrary.wiley.com/doi/10.1029/2011JD015710/pdf
For the uninformed that amounts to 7,600,000 Volts per kilometer of elevator height.
I love it when liberals become "scientists" 'cause they believe in magical thinking - whatever hair-brained scheme they can think up, can happen just because they thought of it.
Lurking'
Can we harvest all those volts to fuel our Volts?