The goal of this review is to assess renewable power sources as alternatives to the batteries traditionally used for remote environmental monitoring. In this review, we first discuss remote sensors and then we: 1) review the power requirements and traditionally used power sources for remote sensors, 2) describe the working principles of the renewable power sources used for powering remote sensors, 3) evaluate the challenges and potentials of the renewable power sources, and 4) review the power management systems developed for remote power generation and discuss how to use them to generate reliable power. In the description of each of the renewable power sources, we include the current status and future directions of the research. We believe that hybrid systems using more than a single renewable power source can provide more reliable renewable power. We conclude that renewable power sources have been demonstrated to be able to generate sufficient power for remote sensors. Because of the environmental risks and cost of operation associated with batteries, renewable energy sources will need to be used to power remote sensors in the near future.