Unfortunately, there's none at this point. There used to be a time wherein bitcoin can be mine with ordinary pc though, but currently only power hardware (ASIC) is capable of mining bitcoin. As for the high energy consumption, this has been debated many times already and has been debunked by many experts in that field. So if you read some articles around the net about it, just ignore, people will always find a flaw in every successful invention throughout mankind's history.