In addition to the design itself, environmental factors affect power. These factors influence the voltage and the junction temperature of the device, which impacts the power dissipation. For more information, see this link in the Vivado Design Suite User Guide: Power Analysis and Optimization (UG907).
Thermal Tip: The -2LI and -2LE UltraScale+™ devices allow a temperature excursion of up to 110°C for a defined period of time, which enables a reduction in the thermal solution cost. For more information, see Extending the Thermal Solution by Utilizing Excursion Temperatures (WP517).