Open access peer-reviewed chapter

Energy Harvesting Technology for IoT Edge Applications

By Amandeep Sharma and Pawandeep Sharma

Submitted: February 7th 2019Reviewed: April 15th 2020Published: January 14th 2021

DOI: 10.5772/intechopen.92565

Downloaded: 73

Abstract

The integration of energy harvesting technologies with Internet of things (IoTs) leads to the automation of building and homes. The IoT edge devices, which include end user equipment connected to the networks and interact with other networks and devices, may be located in remote locations where the main power is not available or battery replacement is not feasible. The energy harvesting technologies can reduce or eliminate the need of batteries for edge devices by using super capacitors or rechargeable batteries to recharge them in the field. The proposed chapter provides a brief discussion about possible energy harvesting technologies and their potential power densities and techniques to minimize power requirements of edge devices, so that energy harvesting solutions will be sufficient to meet the power requirements.

Keywords

  • energy harvesting
  • edge devices
  • IoTs
  • standards

1. Introduction

The technological advancement in energy-efficient low-power hardware vanquished the need of AC current for IoT-based embedded systems, making them suitable for remote applications. The number of new applications including weather data estimation and real-time parameter monitoring is gaining ground with the evolution of different environmental sensors and telemetry applications. Energy harvesting technologies together with low-power platforms and energy-efficient storage technologies allow edge devices, IoTs and embedded systems to work in remote areas.

A report published on energy efficiency of the Internet of things (IoTs) focuses attention on the utilization of edge devices in various applications, and most of these applications are battery driven, which are having limited lifespan (Figure 1). The objective of the proposed chapter is to highlight the potential of energy harvesting technologies that can reduce the dependency on fixed charge batteries and lead to interrupted device operation. The chapter covers the discussion on basic elements of an energy harvesting system, enumerates possible energy resources and quantifies the potential of different harvesting technologies including photovoltaic cells, piezoelectric materials, thermoelectric and electromagnetic generators and electrostatic motors.

Figure 1.

Share of renewable energy resources in total energy consumption, 2016 [1].

2. IoT and IoT edge devices

Internet of things abbreviated as IoT leads to ambient intelligence that is based on the connectivity of people and things and utilizes the adaptive and sensitive electronic environment to address the need of the things around. Diab et al. [2] summarized six essential building blocks of IoT-based system, as shown in Figure 2.

Figure 2.

Essential building blocks of an IoT-based system.

Deployment of IoT-based systems in remote locations demands unattended operation over long time spans. In achieving this target, constant power supply and energy efficiency are the key challenges. Energy harvesting allows on-site charging of the storage devices and thus leads to an uninterrupted sensor node operation. In addition to it, edge devices control the flow of information between two network boundaries. Basically, the edge devices are utilized by service providers and act as entry and end points for a network. Their primary functions include processing, filtering, translation and storage of data and transmission and routing of data within the network [3].

In order to attain intelligence systems with advance features and to gain more computing power, IoT-based applications make use of edge devices. This process of using logical physical locations and decentralized processes is called edge computing [4].

Edge router is the most common type of edge devices and acts as the gateway between the different networks [5]. The primary function of the edge router is to connect a wide area network or a campus network with the Internet. Firewalls are the category of edge devices which are located on the margins of network and perform filtering of processed data during transmission between external and internal networks [6]. Further, different types of sensors/actuators and other types of end terminals also act as edge devices. The figure given below encapsulates the different types of end devices and their role in the network (Figure 3).

Figure 3.

Edge devices in IoT-based system.

If the number of IoT devices is connected in a system, edge devices provide distributed operation among them using dynamic host configuration protocol and domain name systems [7].

2.1 Importance of edge technology

The conventional cloud computing network being a centralized network collects the data at the outermost layer and sends it to the server for further procedure. Limited hardware capabilities of the devices especially near the network edge are the main reasons behind this setup. These devices have limited functionality, limited power capabilities and limited storage capacity that restrict them to process or analyse the gathered data. With the advancement of miniaturization techniques in fabrication, present day IoT devices have capabilities of handling large data. This feature leads to optimized network operations by collecting data at edge terminals and relocating advance processing functions in real time [8].

Thus edge computing ensures processing of data where it is created rather than routing the data to data centres for processing. This feature leads to improved response time to milliseconds and optimum usage of network resources.

2.2 Advantages of enabling edge computing for IoTs

  • Reduced data exposure and reduced network load: Real-time data handling by the edge devices with advance processing and storage capabilities prevent the data to route through the whole network and enhance the offline capabilities by making the apps independent from uninterrupted network connection.

  • Reduced delay: IoT edge computing devices optimize the network performance by reducing delay or latency parameter. By storing and processing the data in edge data processing units, real-time computing is possible instead of communicating with the cloud server for each interaction.

  • Secure communication: Since edge computing architecture deals with distributive nature of collecting, processing and storing the data among the large range of data centres and edge devices, it is not easy for an intruder to demolish the privacy and security of the network [9].

2.3 Industry benefits

  • Efficient massive data processing

  • Local data handling ensures security of sensitive data

  • Quick response time with smart devices and applications

Cloud-based deployments of edge devices and data exchange features between edge and cloud is the next generation build out for 5G communication by telecommunication sector. High-speed network response with very low latency factor is the target where data compilation is carried out at the edge devices and reports are sent to the central cloud for storage. This feature eliminates the unnecessary data movement over the network [10].

3. Energy harvesting technology

Energy harvesting is a process through which energy is derived from external resources and captured energy is converted into electrical energy through energy harvesting device. The various resources are tabulated in Table 1 that can be used for conversion.

S. No.Form of energySource
1Light energySolar energy from sun (outdoor/indoor) [11, 12]
2Kinetic energyVibration, rotation, motion [13, 14, 15, 16]
3Thermal energyHuman body, industry [17, 18]
4Atmospheric energyPressure, gravity
5Radio frequencyAntennas, radio frequency spectrum [19]
6Biological/chemical energyDiffusion, radioisotopes
7Hydro energyKinetic energy from water

Table 1.

List of various energy resources and their source.

Basically, an energy harvesting system comprised of three main components including application specific transducer, an interface circuit with or without storage device and receiver. The transducer or energy harvesting unit harvests the energy from the ambient sources and converts them in electrical form. The function of the interface unit is to extract maximum amount of energy from the harvesting unit and make the energy level compatible with the specific receiver or load. This has been accomplished with different power management approaches including voltage regulation or rectification [20], etc. The receiver may include different sensors, transducers or any other electronic circuit. The presence of storage unit avoids the start-up problem and energy depletion state in case of large interval in harvesting cycles. Figure 4 shows the basic block diagram of an energy harvesting system:

Figure 4.

Basic building blocks of an energy harvesting system.

4. Requirement for energy harvesting in IoT

Energy harvesting is a promising solution to power IoTs especially when they are installed in inaccessible areas and regular battery maintenance is not possible. Energy harvesting approach extends the life cycle of the device and eliminates the constraint of fixed charge batteries as an energy source. Some key factors are enlisted below that highlight the requirements for energy harvesting technology in IoT applications.

4.1 Power

The energy harvester should generate power at least of the order of milliwatts to sustain in IoT domain applications. Table 2 shows the potential production of different energy harvesting technologies.

S. No.Energy harvesting technologyPotential productionIndustrialization
1Thermoelectric10 μW–1 kWWidespread production
2Photovoltaic1 μW–1 MW
3Electrodynamic0.1 μW–1 MW
4Piezoelectric10 μW–100 W
5Capacitative electrets movement harvesting0.1 μW–1 mWResearch
6Pyroelectric
7Capacitive without electrets0.1 μW–1 MW
8Triboelectric
7Radio frequency waves0.1 μW–1 mWLimited production
8Magnetostrictive10 μW–1 MWMajor trials

Table 2.

Different energy harvesting technologies and their potential production [21].

In conjunction to the survey given in Table 2, an overview of power consumption of different electronic modules has been depicted in Table 3. The survey reflects that the operating range of different IoT devices and sensors is in between 0.1 μW and 1 W, which can easily be handled by energy harvesting devices. Since ambient resources are stochastic in nature, energy demand and supply may not be time synchronized; the presence of backup storage devices and effective power management electronics is essential to deliver power from harvester to IoT devices in time.

S. No.Electronic modulePower range
1Watch/calculator1 μW
2RFID tag10 μW
3Sensors/remotes100 μW
4Wireless sensors/hearing aid1 mW
5Bluetooth transceiver10 mW
6Global positioning system(GPS)100 mW

Table 3.

Overview of power consumption by different IoT modules and sensors [22, 23, 24].

4.2 Size scaling

With the advancement in integrated circuit technology, the size of the IoT devices is not an issue as number of features can be integrated on a single chip. The battery used in conventional module designs generally has a life cycle of 1 year and is the key factor in overall weight and size of the module. As an alternative to the fixed charge batteries, the size of the energy harvesting unit is application specific and should not be greater than the previous energy storage. The scalability of the energy harvesting unit with the size of IoT module should be ideal.

4.3 Cost factor

Conventional battery is an economical product because of the mass production, which leads to cost-sensitive production of battery-driven IoT devices. On the other hand, integrating energy harvesting technique into the module will increase the cost. This cost will include the component cost together with the redevelopment cost of the device because implanting an energy harvesting device on the top of the conventional module is not a practical solution and whole internal design gets modified. Figure 5 shows the development process of rechargeable sensors and validates the above statement.

Figure 5.

Development procedure of rechargeable sensors.

5. Constraints and potentials of energy harvesting technique

5.1 Constraints

The constraints in practical implementation of energy harvesting techniques in IoT domain are as follows:

  1. High cost as compared to the conventional batteries is the most important constraint to be considered.

  2. The second barrier is the size of the harvesting module, which increases as per the energy demands.

  3. Energy storage unit is essential for uninterrupted sensor node operation.

5.2 Potentials

Although the additional cost is a barrier for mass production of harvesting modules and power requirements of some technologies may not be in the range of harvesting technologies, there are high possibilities in wide spread adaption of energy harvesting technology. Few of them are enlisted below:

  1. The estimated life cycle of an energy harvesting module is above 5 years. In a survey, it has been observed that some energy harvesting units are working smoothly from the last 15 years without hardware degradation [25]. Thus, regular hardware servicing is not required in inaccessible locations.

  2. The evolution of advance low-power electronic hardware together with the cloud computing for data processing further reduces the energy consumption in electronics and increases the feasibility of energy harvesting.

  3. A high factor of energy saving can be in building automation where copper wires, materials, installation and maintenance cost can be reduced by energy harvesting approach.

  4. With the growth of IoT industry, more energy harvesting modules will be implemented that will in turn reduce the cost.

6. Energy harvesting standards

Interoperability between different end systems is an important criterion for the successful adaption of energy harvesting techniques in different applications. To achieve this target, there are three standard policies, which are depicted in Figure 6. The EnOcean Alliance follows the standardization of communication profiles (EnOcean Equipment Profiles) to ensure that the entire product range including rechargeable sensors, wireless switches and controls can communicate with each other. The EnOcean wireless standard is geared to wireless sensors and wireless sensor networks with ultra-low-power consumption and also includes sensor networks with energy harvesting technology.

Figure 6.

Implementation of energy harvesting platform.

The EnOcean wireless standard became the standard ISO/IEC 14543-3-10:2012 in 2012. The standard is applicable to Information technology, Home electronic system, wireless short packet protocol and optimized for energy harvesting, its architecture and lower layer protocols. The proposed protocol supports energy harvested products for IoT sensors and switches designed without wires and batteries. The standard allows low-power consumption of sensors and switches by transmitting multiple short transmissions and appropriate frequency bands with adequate signal propagation and minimum interference.

6.1 Socio-economic applications

In this section socio-economic application of energy harvesting technology has been discussed, and their market share has been depicted in Figure 7.

Figure 7.

Energy harvesting market share under different sectors.

  • Energy harvesting power sensors

Renewal of battery-operated power sensors with energy harvesting-based rechargeable wireless sensors is the prime factor in the growth of energy harvesting market. Rechargeable sensors are becoming the first choice for the deployment in remote or inaccessible locations where it is not possible to replace the batteries frequently especially in offshore oil, gas systems or sensitive military areas [26]. Further, autonomous or rechargeable sensors are environment friendly as they do not contain any harmful metal or chemical for the environment.

  • Benefits for primary industry

The energy harvesting market in primary industry sector was sized at EUR 130 million in 2014 and predicted to reach EUR 380 at the end of 2020 [27]. To enhance the reliability and availability of industrial processes, energy harvesting devices are employed in primary industry sector.

  • Benefits for defence industry

Energy harvesting technology has been increasingly used in defence sector as it leads to the way where heavy battery packs are replaced by autonomous or rechargeable devices. Solar photovoltaic-based autonomous aerial unmanned vehicles called Drones are the great achievement for military applications. According to the latest survey, energy harvesting-based defence applications target EUR 730 million by 2020 [27] (Table 4).

ApplicationEdge devicesEnergy source
Smart industryRemote control of machinesMachinesMain power supply
Real-time monitoring of machine wearAppropriate sensorsMain power supply
Diagnostics of machinesAppropriate sensorsMain power supply
Surveillance of maintenance conditionsAppropriate sensorsMain power supply; energy harvested source
Inventory management and asset trackingRFID tagPassive energy source; energy harvested source
Smart pipeline managementDedicated sensors, e.g. thermal, pressure, humidity, etc.Energy harvested source

Table 4.

Application and energy sources of edge devices for smart industries.

  • Benefits for transport industry

Different transportation media offer various forms of energy that can be harvested by different means. For instance, solar panels installed on the road collect the solar energy and convert it into electrical form through walking or driving. Similarly, vibration energy generated through various transportation means can be utilized for energy harvesting. It is estimated that transportation sector can target EUR 310 million by 2020 [27] (Table 5).

Application areaApplicationEdge devicesEnergy source
Smart transportationSmart roadsEnergy collector roadsPressure- or vibration-based energy harvesting technology
Smart sensor in roadsVibration, RF or thermal-based energy harvesting technology
Smart lightening system for roadsMain power supply; solar- or vibration-based energy harvesting system
Real-time monitoring of traffic congestionGPS system in carsOn board or rechargeable battery
Car-to-car communication systemInbuilt devices in carOn board or rechargeable battery
Car-to-infrastructure communication systemInbuilt devices in carOn board or rechargeable battery; solar- or vibration-based energy harvesting system

Table 5.

Application and energy source of edge devices for smart transportation.

  • Benefits for residential and commercial sites

Energy harvesting will be an essential feature for the upcoming trend of home automation and smart housing. This is because of the reason that energy harvesting technology will reduce the large-size batteries for mobile devices. Rapid growth of IoT devices is also possible with energy harvesting as it facilitates rechargeable power supply with low installation and maintenance cost. The market value of this sector is expected to reach EUR 1750 million at the end of 2020 [27] (Table 6).

Target areaApplicationEdge deviceEnergy source
Smart homeHome automationActuatorsMain power supply
CameraMain power supply
GatewayMain power supply
Smart sensors including humidity sensor, temperature sensor, fire sensor and door sensorEnergy harvesting source of light or thermal energy
Sensors connected with mainsMain power supply
Smart lightening systemLED bulbsMain power supply
Hub; gatewayMain power supply
Smart light switchesVibration- or pressure-based energy harvesting source
Smart workplaceWorkspace automationMain serverMain power supply
ActuatorsMain power supply
SensorsEnergy harvesting source of light or thermal energy
GatewaysMain power supply
Control systemReporting time, access controlMain power supply
BadgePassive source of energy
Gas sensor, motion sensor, smoke sensorEnergy harvesting source of light or thermal energy
Window/door sensorEnergy harvesting source of light or vibration energy

Table 6.

Application and energy source of edge devices for smart home and working area.

7. Communication protocols used in IoT systems

Various communication protocols with their different positive and negative attributes have been used to communicate with the network through IoT devices. Table 7 enlists different communication protocols along with their properties.

Communication protocolPowerData rateDistance covered
ZigBee50 mW250 kb/s; for medium data rate applications25 m; for medium distance communication
Wi-FiGreater than 500 mWGreater than 100 Mb/s; for high data rate applications10 m; for low distance communication
LoRa100 mW1 kb/s; for low data rate applications500 m; for high distance communication
Bluetooth10 mW1 Mb/s; for high data rate applications10 m; for low distance communication

Table 7.

Different communication protocols with their properties.

8. Summary

Different levels of technical maturity are available with different types of ambient energy resources and corresponding energy harvesting techniques. The magnitude of available power from different sources ranges from microwatts to milliwatts. This range is suitable for a variety of IoT devices and related applications. Some practical implementations of energy harvesters are surveyed in the literature that offers power to drive IoT devices. But there are various technical constraints that limit the worldwide implementation of energy harvesting technology. These issues need to be addressed to satisfy the future demands of the world.

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License, which permits use, distribution and reproduction for non-commercial purposes, provided the original is properly cited.

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Amandeep Sharma and Pawandeep Sharma (January 14th 2021). Energy Harvesting Technology for IoT Edge Applications, Smart Manufacturing - When Artificial Intelligence Meets the Internet of Things, Tan Yen Kheng, IntechOpen, DOI: 10.5772/intechopen.92565. Available from:

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