My usual spreadsheet, people have said it's been useful in the past.
Thx Tigggger. Very helpful.
I guess there's no way to include the halving in your calculation. So we need to be aware the BE time (aka ROI) is likely longer for each of the electrical rates in your chart.
Only for the ones that extend past the halfing date - mid-July is appx. 290 days out.
On the other hand, this chart doesn't take diff increases into account at all, which is why I prefer to use a site like bitcoinwisdom.