So I was messing around with redstone and I found a way to have activated pistons without power, it's hard to explain but basically you need a piston facing downwards, (I'm not sure if it works in any either direction) then you have to put a sticky piston 2 blocks away and one block up, make sure your sticky piston is facing the one that is facing down, then place a redstone block on the sticky piston that you moved away. Power the sticky piston with the redstone block, then unpower it, and you have an unpowered activated piston. You can break the other piston and redstone block but as soon as the unpowered activated piston gets updated, it will deactivate and go back to normal.