If I have only Special Energies attached (no Basic Energy) and use Tornadus' "Hurricane" attack, do I have to discard an energy or what?
If you don't have any Basic Energy cards attached to Tornadus, you simply ignore that part of the Hurricane attack.
Source: PUI Rules Team (2011-11-03)

Relevant cards

Note: All applicable cards may not be listed below.
BW2_89
BW2_98