Passivity is a necessary condition for a system's stability, meaning that an energy generating system may readily become unstable. Energy-aware actuation can enforce passivity by monitoring the amount of energy that is exchanged with a system, while using an allocated energy budget to execute a task. Careful communication of the energy budgets is important to prevent accidental generation of energy. Therefore, this paper proposes an energy transaction protocol to communicate energy budgets in a distributed robotic system to guarantee that passivity is kept. Simulations are performed with a model of the protocol that is applied to a simulated unreliable communication channel. It is verified that the proposed protocol keeps passivity in the system, while a naive communication strategy either violates passivity or is unnecessarily dissipative.