Electric energy availability in rural and remote locations is very
different from that in cities and urban settings, due to distance and investment unbalances. Having the ability to increase that energy availability without the need to install large infrastructures or to change
landscapes or water flow is of particular interest, namely in the current
context of environmental concerns. Typically, wastewater treatment
facilities share the same energy challenges as those from rural and
remote locations, which, in turn, highlights the applicability and usefulness, particularly to limit the energy consumption, of low power
wireless network smart sensors [1]. This monitoring solution can
address power outflows for water monitoring and stream control.
Existing smart sensors have their biggest limitation in power: the batteries usually applied have a short lifetime, needing frequent recharging
or replacement, which limits the convenience of a wireless operation
and increases operation and maintenance costs [2]. Bibliographic
records point to 74% of all the consumed power of a sensor node being
directed at the transceiver module [3]. There are three intervention
opportunities: to decrease the power consumption of this module; to find
a more efficient rate to transmit/receive data, decreasing the time for
which the module has to be turned on; and to come up with sustainable
energy alternatives that can account for all the power needs of these
circuits [4].
Power can be provided to the smart sensor through a connection to
the main power grid, with a suitable power transformer, using conventional batteries or harvesting energy from the operating environment. The connection to the main power grid severely hinders the
versatility of the devices, namely their ability to be used at different
locations. Even though wires are the most reliable, faster and safest way
to power anything of electrical nature, the connectors are a weak point,
susceptible to moisture and dust and the wiring always limits the
portability of the device [4]. Batteries have limited lifetime cycles and
cannot be recycled: their internal fuel cannot be replaced and, once
spent, the battery has no more use, making them pollutant. Fuel cells, on