I think I found a bug, it will not let me play thunderbolt due to not having enough energy, however I have 8 energy and thunderbolt only costs 3. all that i have done this turn is play meditate 3 times, the reason i don't have 9 energy is that the game charged me one energy for the second meditate even though it is supposed to cost zero.
Edit: attempting to play thunderbolt killed the orc however I did not lose energy or the card and it said I did not have enough energy.