Read manufacturer manual: http://h10032.www1.hp.com/ctg/Manual/c05819688 (archived link).
Install PowerTOP (https://01.org/powertop/) and TLP (https://linrunner.de/en/tlp/tlp.html) tools.
sudo add-apt-repository ppa:linrunner/tlp
sudo apt-get update
sudo apt-get install powertop tlp tlp-rdw