Intrigued by various articles on https://grano.la/ I thought I would test it out. It is free after all.
The concept is very simple: you install the client, and it controls the power of your computer so that it's always using the minimum amount of energy required for a specific set of tasks. I may have read between the lines there but you can read it for yourself if you don't believe me.
The site itself does not talk about stability, but I found that all my applications remained stable and I have not experienced any software problems.
Under Ubuntu I use a nice little widget called the CPU Frequency Scaling Monitor which allows me to easily switch the processors into certain frequencies or scheduler modes.
Unfortunately since installing Granola the frequency scaling does whatever the Hell it likes and I often find it stuck at full speed (as opposed to on demand). So it appears it has made permanent changes despite the fact I have now removed it. Looks like I'll have to bury myself among the man pages to find out how to resolve this. Permanently. Again.
The nice people over at Granola do ask for feedback. So, I can now send them this!
Also, I'm a bit dubious about statistics for my laptop between 02:00 and 18:00 on the 17th of June that claims my power usage was only 3 watts total. Seems unlikely - I'm sure the hard drive alone uses more than that and it never gets the chance to spin down (background processes).
Over to Granola... (I'll update once resolved).