Also supported on older X series in Linux (the tp_smapi kernel module), and probably on many others. It's also possible to set the thresholds from Windows once and they'll persist even when you turn off the laptop.

Actually, the feature is present on a lot of Lenovos (even non-thinkpads). My anecdotal experience it that it works quite well.

However it's only accessible from their energy management tray program on Windows, so if you do a clean Linux install right away, you won't even know about it. You need to try the kernel module pointed out in the sibling comment.