Fulminate

Fulminate creates an icon, by default to the left of the centre of the screen and a bit higher, when a shaman's Lightning Shield ability reaches 7 or more charges, by default. The icon's opacity translates to how many charges remain, with it becoming increasingly solid as it nears maximum from the minimum amount.
This can help shamans in maintaining higher damage output by assisting in effectively using Earth Shock when Lightning Shield has a high number of charges.

Check out the Fulminate Options AddOn if you would like to able to customise the AddOn to set the minimum charges for when the frame begins appearing, and to move it into your desired position with the lock/unlock and advanced positioning features.