Focus-swapping into a +0 energy weapon set, or even a -energy weapon set, can help "hide" some energy.
This is especially useful with Rebirth, which already drains all energy, for an instant cast and no additional penalty.
Note that this skill removes all energy after energy bonuses gained from skills like Elemental Attunement and Auspicious Incantation have been applied. This means that if you use this glyph to cast Meteor Shower with Elemental Attunement on, you will lose 25 energy from the initial casting of the spell, gain 13 energy from Elemental Attunement, then go back to 0 because of Glyph of Essence.
Consider using this with difficult to cast spells that would already drain the energy pool of a non-elementalist primary, such as Well of the Profane.
Consider using this skill to recast Ether Prodigy to get rid of the sometimes tragic ending effect.
This is the only Glyph that differs from the conventional image with a character in the middle. Both the texture of the ring and directions of the points are different.