In Team Battle, can I use my Venusaur to switch Grass Energy between my teammate's Pokemon (not moving them between owners)?
Yes.
Source: WotC Chat (2002-06-27)

Relevant cards

Note: All applicable cards may not be listed below.
WOTCB2_18
WOTCB2_18
WOTCB1_15
WOTCLC_18