**3. Energy harvesting**

In general, to harness energy from the environment is not a novelty, for instance, solar and wind energies are harnessed for centuries. Despite harnessing energy to high-power applications like industries and cities, which wind and solar power plants are good examples, harnessing energy to low or ultra-low-power applications gave rise to the expression "Energy Harvesting."

Energy harvesting is defined as the process of capturing very small amounts of energy from naturally occurring energy sources surrounding the low-power electronic device to be powered, accumulating, storing and converting them to electrical energy for powering the device [11–17].

*The possibility to harvest energy from the environment to power electronic circuits became a reality due to the advanced in microelectronic technologies that occurred during the last decades. With this advance, the size of electronic devices has becoming so small, make possible the development of tiny portable devices integrated in objects like watches, glasses, clothes, etc., as well as the energy needed to power these devices has decreased drastically* [16]*.*

Some possible energy sources can be solar light, thermal, mechanical vibration, electromagnetic waves, and so on. For example, a wireless seismic sensor powered by solar cells was the first to be installed in a bridge in Corinth, Greece [17]. Another example, bridges vibrate when vehicles travel over them, and such vibrations have a kinetic energy that can be used to generate electricity [4].

**Figure 2.** Basic structure of an energy harvesting system.

the cell is a cylindrical battery [9]) and considering, as an EV default battery size, a battery formed by 6831 18,650 cells. That is also exactly the battery used in the luxury Roadster intro-

**Figure 1.** Internal structural design of a cylindrical Ni-cd battery [6]. Copyright Wiley-VCH Verlag GmbH & co.

In this way, it is expected between 3.2 million and 4.3 million of EV-battery-equivalent connected devices by 2020 at which means that IoT battery impact is about 25% of the EV battery

duced by Tesla Motors [10].

KGaA. Reproduced with permission.

28 Energy Systems and Environment

Naturally occurring energy sources can be roughly classified as **environment energy sources** and **human energy sources** [16]. Examples of human energy sources could be kinetic energy coming from arms and legs movements, and thermal energy used to power wearable sensor [18, 19].

In order to compare and to obtain a general view of different energy harvesting propositions,

Energy Resources in Agriculture and Forestry: How to be Prepared for the Internet of Things…

http://dx.doi.org/10.5772/intechopen.74940

31

Even though IoT has gotten substantial attention recently and is a key factor in several paradigms like Smart City [24], Smart Building [25], Connected Cars [25] and Industry 4.0 (Smart

Below are some of the concepts related to IoT, which are described taking into account

• **The Thing itself**: A **Thing** (also called smart object) is any object with embedded electronics (microcontrollers, transceivers for digital communication, sensors, actuators, networking processing support circuits, etc.) that can transfer data over a network—without any human interaction [27]. Things can be home appliances, surveillance cameras, monitoring sensors, actuators, displays, vehicles, smart phones, tablets, digital cameras, doors, win-

• **The network of Things**: IoT is a communication paradigm that envisions that objects of everyday life, turned into a smart object, be able to communicate with one another and

• **Service provider**: IoT is characterized by its pervasive nature, meaning that it can be everywhere, enabling nonhuman direct interaction with a wide variety of everyday things and fostering the development of a number of applications. Those applications can make use of the potentially enormous amount and variety of data generated by such Things to provide

• **Human benefit**: IoT has as its ultimate goal to create benefits for human beings, where smart objects around people know what they like, what they want and what they need and act accordingly without explicit instructions [28] and to promote an enhanced level of

Taking into consideration the abovementioned concepts, then the IoT can be defined as a network that links smart objects (Things) worldwide, which are capable of: processing, sensing, actuating and communicating with one another, originating directly data to the Internet without any human interaction and providing services to citizens, companies and public

As described at the beginning of this section, several paradigms related to "smartization" in a given context (e.g.*,* Smart City, Smart Building and Smart Factory) is taking place in the word. In this perspective and considering that the current environmental issues of the planet, it is

Factory) [26], it does not have a standard or globally accepted definition.

dows or literally any object that turned into a smart object.

with the users, becoming an integral part of the Internet [24].

new services to citizens, companies and public administrations [24].

**Table 1** shows the power density achieved by them.

**4. Internet of natural things**

awareness about the world [29].

administrations.

considering:

Nevertheless, there are some energy sources for energy harvesting applications that occur not precisely naturally, like those originated by electrical, magnetic, and electromagnetic fields, but they can be available in the environment. For example, radio frequency (RF) signal are being harvested to power sensor at a distance [20]. RF energy harvesting is become a good option to power IoT devices.

**Figure 2** shows a basic structure of an energy harvesting system. Its main blocks consist of:


Utilizing energy harvesting systems as main energy sources is turning to be one of the most promising systems for batteryless low-power electronic devices. However, energy harvesting systems can be combined to batteries (or other energy storages) as a solution to reduce the battery's lifetime limitations or to decrease the dependency of battery performance [21, 22].


**Table 1.** Power density of different energy harvesting propositions [15, 23].

In order to compare and to obtain a general view of different energy harvesting propositions, **Table 1** shows the power density achieved by them.
