  In this paper, we examine the potential for a reconfigurable intelligent
surface (RIS) to be powered by energy harvested from information signals. This
feature might be key to reap the benefits of RIS technology's lower power
consumption compared to active relays. We first identify the main RIS
power-consuming components and then propose an energy harvesting and power
consumption model. Furthermore, we formulate and solve the problem of the
optimal RIS placement together with the amplitude and phase response adjustment
of its elements in order to maximize the signal-to-noise ratio (SNR) while
harvesting sufficient energy for its operation. Finally, numerical results
validate the autonomous operation potential and reveal the range of power
consumption values that enables it.
