On the wiki for Ward Energy Lore (WEL), it states that it does not affect Block Warding Energy (BWE). However, on both the Warding Energy and Energy Shroud wiki entries it says it does.
By using a character editor to play around with some numbers and mousing over the Sigma sign on the inventory page while increasing WEL, I noticed no changes to any stats.
I'm playing the Steam version of Sacred 2 Gold without the Community patch.