Capacitance matrix evaluation (electrostatics)

Hello everyone,

i have a question about the capacitance calculation method. In comosl example "Capacitance matrix", it explains that the electrostatics model use the Charge volateg relationship (Q = C* U) to calculate the capacitance matrix by stationary study.

But in comsol documentation" AC/DC>Modeling with the AC/DC Module>Lumped Parameter>studying Lumped parameter", it says that electrostatics uses the energy method by stationary study.

Is there something wrong??? Which is right?

Thank you for your help

traxer