They do stack, but it's kind of overkill. Each proc works independently, so you'll get two 40% chances per energy orb, it's not often that it procs twice, but when it does...

What is so good about arcane energize?

Arcane Energize is an Arcane Enhancement that provides a chance to gain additional energy for you and nearby allies whenever you pick up an Energy Orb, with a 15 second cooldown between uses.

Does arcane energize work for yourself?

It restores energy to yourself and any allies within a radius. It does.