In reply to Ciro:
I'm a long way from being an expert either but as far as I'm aware one of the more successful alternative blockchain models (instead of bitcoins proof of work model) is proof of stake, which allocates responsibility for verifying transactions according to the amount of asset the miner holds, instead of it being a competition where the miner with the most computational power wins. Like I say, not an expert but it sounds at the very least less wasteful.
Proof of Stake (PoS) Definition (investopedia.com)
Edit: for some reason my link isn't pasting properly and I'm not computer savvy enough to add a link into the text, but I'm sure you can google it!
Post edited at 16:36