Why does facilitated diffusion does not require energy?

Question

Why does facilitated diffusion does not require energy?

Answer 1

because it goes high to low

since there is already high pressure on high side it doesn't require energy

Answer 2

Because facilitated diffusion involves transport of polar substances or ions DOWN their electrochemical gradient i.e. from high conc. to lo conc. Only aim of facilitated diffusion is to provide hydrophilic (polar) protein channel to transport molecules across hydrophobic interior of lipid bilayer membrane.

Energy is required (in the form of ATP or co-transport) only in order to transport a molecule(s) AGAINST it's gradient i.e. from low to high concentration.