Energy Security for Overseas Troops Act This bill requires the Department of Defense to establish a program to assist partner country military forces in developing and maintaining military-wide transformational strategies for operational energy. The purpose of this program is to promote the readiness of U.S. and partner country military forces for missions in a contested logistics environment by reducing reliance on fossil fuels and employing more diverse and renewable operational energy sources. (A contested logistics environment is one where U.S. or partner country military forces engage in conflict with an adversary that presents challenges in all domains and directly targets logistics operations, facilities, and activities.)