I think you are being a bit silly. I just plugged the numbers into an online cost calculator.

That is extra 10 watts, is less than £2 a month in the UK. Drives are about 5 watts idle and I have 6 of them.

The NAS costs me about £20/month. Which isn't too crazy IMO. The UK has some of the most expensive energy prices in Europe.

I will probably be upgrading the board to something better in a few years and see if I can put in a GPU for some AI bits and pieces.