For a team of heterogeneous robots executing multiple tasks, we propose a\nnovel algorithm to optimally allocate tasks to robots while accounting for\ntheir different capabilities. Motivated by the need that robot teams have in\nmany real-world applications of remaining operational for long periods of time,\nwe allow each robot to choose tasks taking into account the energy consumed by\nexecuting them, besides the global specifications on the task allocation. The\ntasks are encoded as constraints in an energy minimization problem solved at\neach point in time by each robot. The prioritization of a task over others --\neffectively signifying the allocation of the task to that particular robot --\noccurs via the introduction of slack variables in the task constraints.\nMoreover, the suitabilities of certain robots towards certain tasks are also\ntaken into account to generate a task allocation algorithm for a team of robots\nwith heterogeneous capabilities. The efficacy of the developed approach is\ndemonstrated both in simulation and on a team of real robots.\n