Power Efficiency and Resiliency Act or the POWER Act - Amends the Internal Revenue Code to: (1) allow a 30% energy tax credit for combined heat and power system property and increase the capacity limitations for such property, (2) extend until December 31, 2018, the placed-in-service deadline for such property, and (3) allow a 30% energy tax credit for waste heat to power property (property comprising a system generating electricity through the recovery of a qualified waste heat resource) placed in service before January 1, 2019.