He's talking about transmission losses in the power grid. Whenever you pass current through a conductor it generates heat. Think of all the miles of transmission lines and transformers between you and your friendly neighborhood coal plant. Every inch of it gives off heat which constitutes energy leaking out of the system. Transmission losses alone are not that bad, but total system efficiency for electricity is dismal.
Here's some rough math to illustrate.
A ton of decent coal can release
27million Btus of heat when it's burned.
The boiler, turbine and generator at your average coal plant will "capture" perhaps
33% of this energy and turn it into electricity.
The DoE says that the transmission grid is around
90% efficient.
Based on the estimate below;
my electric stove is roughly
25% efficient.
Your inductive cooktop is
83% efficient.
So how much coal to boil a gallon of cool (fifty degrees) tapwater ? (I love spaghetti)
My electric cooktop would require 1.5Lbs of coal to be burned (7% overall efficiency).
Your inductive cooktop would require .45 of a pound (24% overall efficiency).
A perfect system that burned coal and used its heat at 100% efficency (impossible) would require .11 of a pound of coal.
Estimating my cooktops efficiency:
How long does it take to boil a quart (2lbs) of water? I think my 1500watt electric burner used to take about fifteen minutes, thereby consuming 1280Btus of electricity. The actual amount of useful work done in raising the temperature of two pounds of water by about 160 degrees farenheit is about 325 Btus. So my stovetop burner is like 25% efficient.