I would assume, that most touch modules run over USB internally. Wether they are powered over USB is another question though. There are third party touch addons for monitors that are powered over USB. I guess it depends on the specific model.
As per above, the touchscreen part should be a separate USB device, so as long as it isn’t bundled with all of the other cables in a single connector, then you may be able to just unplug it.
That being said, my laptop has stupid long battery life (over 9 hours) and has a touch screen. It seems very comparable to other models with the same N3700 processor, battery, and ~11" screen but lacking a touchscreen.
You could look for teardowns of your specific model online and try unplugging it yourself if it is an option, or even measure the current if you are adventurous. I’d imagine something with a huge screen (>17") might use more power than my netbook sized model. Barring that, I’d say doing anything and everything except that would be more likely to yield better results.
If it is connected to a USB 2.0 hub, then I believe the entire hub can only provide 500mA, so it almost certainly must draw less than that. I did a quick search and saw an add-on touchscreen overlay for a 17" monitor and it says, “Current：Typical [email protected]+5VDC; 350mA, maximum” which means absolutely nothing about your device and is only a single point of reference.