Second-hand Supermicro boards with 6, 8, even 12 SATA ports, 8-16 GB of ECC RAM, a preinstalled CPU, and often a passive radiator are pretty accessible or eBay or suchlike. Of course they are old, but if they did not break after 5-7 years in a server rack, most likely they're not going to break for 10 more years in a less demanding environment at home.

Not low power. Electricity over 10 years would cost 10 times more than the board.