It doesn't take any electricity to run a mining pool. All you do when you run a pool is basically have the wallet open and you accept shares from your miners and when a block is found your split the reward based on the equal share count for every miner. This only uses some CPU power and not much else. It might be more dependant on larger SSD and RAM depending on what type of coin pool you want to run. From what I heard Ethereum will require more resources than some new alt-coin based on a Bitcoin clone.
It used to be profitable to run these back in the day but these days people just stick to the big pools. And usually won't switch to a newer pool due to trust issues and the fact that if there aren't enough miners it will take a long time to find a block.
Aye. Unfortunately a lot of the pools that invested in infrastructure to improve them have gone bust as a result, so certainly one to cost up carefully.
