Here are some basic considerations for a viable energy harvesting system. First of all, the energy source has to be available and harvestable. Next, it could be in an environment where it is difficult to power the device and cords may be prohibited due to the cost or the nature of the application itself. Along with this, it may be too costly to replace or maintain the battery. An example would be a wireless sensor network in an industrial chemical plant used to monitor the process. In this example, servicing of the wireless sensor network may require the plant to shut down.