There is an incorrect comment on the Design News story.
".... So that when half the energy in one's 12 volt power pack is used up the terminal voltage is six volts. So to utilize most of the stored energy one must be able to extract power down to zero volts."
Not true, the enery is CV^2/2, so the majority of the energy is extracted in the initial voltage drop. For example, a 100F capacitor charged to 2.5V will drop to 1.77V after half the energy is extracted.