NordicHardware has an article where Fredrik Andersson steps you through the process of undervolting your laptop. Although as Andresson points out, the terminology is not an accurate reflection of the adjustment being performed, undervolting refers to stepping down the voltage that your CPU requires by several fractions of a volt. The end result of the tweaks that NH guides you through is up to ten minutes more running time and several degrees less heat dispersion, all without effecting the notebook's performance.