Searched "Speed of Light" and nothing came up, my apologies if this is in Elite as I am unaware of what that section contains.
The talent Speed of Light - Spell - World of Warcraft increases your spell haste by 30% for your next Flash of Light, Holy Light or Divine Light and your Holy Radiance grants you 60% movement speed.
Well, with the spec below I have found that it also grants you 30% spell haste for Exorcism. Exorcism also does not remove the buff so you get 5 seconds of 30% faster exorcisms.
Talents I'm using: WoW Talent Calculator - Sigrie.