This article investigates the pivotal role of Energy in trial-and-error evolution (TAEE). I commence by discussing the Uncertainty principle, which introduces fundamental randomness to physical phenomena and imparts random variability to the TAEE (trial and error evolution). As Energy is the sole component of our Cosmos, the TAEE reflects in Energy and its changes: its exertion capabilities, storage, and ad hoc planning (of Energy exertion.) I then investigated TAEE as reflected in the emergence of intelligence. The Least action principle controls Energy movement in space-time; thus, intelligence emergence directly connects to structures' ability to use the Least action principle. For example, first-level nonintelligent structures (e.g., elementary particles, simple replicating molecules) cannot plan a path, and the Least action principle completely predetermines their infinitesimal movements. They cannot control their Energy exertion, store Energy, or plan ad hoc. After a long process of TAEE, intelligent structures emerged with advanced Energy control, robust Energy storage, and ad hoc planning, allowing complete ad hoc path planning and the ability to make unrestricted mid-course path adjustments. This progression underscores the intricate relationship between Energy dynamics, trial and error evolution, and intelligence evolution.