2.2.2. Demand Response

Demand response is a change in the power consumption of an electric utility customer to better match the demand for power with the supply [71]. Demand response can be used to reduce peak demand, which can help to avoid blackouts and brownouts. IoT sensors can be deployed to manage energy demand by adjusting energy usage during peak demand times. This can help reduce the need for costly power generation and distribution infrastructure [3,69].

#### 2.2.3. Distributed Energy Resources (DERs)

Managed distributed energy resources (DERs), such as solar panels and wind turbines, enabled energy providers to optimize energy distribution utilizing IoT sensors. [21,69]. DERs are becoming increasingly important as the electricity grid becomes more decentralized. As more and more people generate their own electricity, DERs will play a key role in ensuring the reliability and resilience of the grid [71].

### 2.2.4. Grid Monitoring

IoT sensors can be deployed to simultaneous monitor grid performance, enabling utilities to respond quickly to any problems or outages. This can help reduce downtime and improve reliability [69,72].

### 2.2.5. Power Quality Monitoring

The quality of electricity being distributed can be monitored, enabling utilities to identify and resolve any issues that may affect power quality using IoT sensors [72]. A combination of IoT devices, data analytics, and communication technologies are required to implement smart energy solutions. However, the potential benefits include reduced energy consumption, which improves efficiency, and environmental impact, which has a significant impact on both individuals and communities [3,69].

#### 2.2.6. Smart Lighting

Smart lighting employs IoT sensors to adjust lighting levels based on occupancy and daylight levels. This can help reduce energy consumption and save costs while still providing adequate lighting. Another M2M application was implemented in smart homes, smart offices, smart cities, and streets [4,14]. Smart lighting systems impact energy savings in the cities around the world. Currently, 55% of the world population is residing in urban cities. As the growth accelerates rapidly, 68% of the population are predicted to live in urban cities by 2050 globally. By 2030, there are 43 megacities with more than 10 million residents predicted [73]. These statistics pose challenges to city management and smart buildings in terms of energy utilization efficiency. As smart cities tend to be green, the sources of greenhouse gas (GHG) emissions must be reduced [14]. Electricity is one of GHG emission sources which represents 27% of the total US GHG emission in 2018 [74]. The dominant electricity source of GHG emissions is the residential and commercial section, which represents 32% [74]. Reducing GHG emissions can be accomplished by reducing electricity usage and peak demand by increasing the utilization efficiency in residential and

commercial buildings. Based on the report published by the World Council on City Data (WCCD) in 2017, GHG emissions were reduced by 63% in the city of Los Angeles due to switching to light emitting diode (LED) lighting [14]. By 2025, the global call of switching lighting systems to 100% smart LED lighting will contribute to the reduction of the lighting share of the global energy consumption from 15% to 8% [75,76].

#### 2.2.7. Energy Storage

The use of energy storage solutions such as batteries and capacitors can be optimized [69]. This can help reduce energy waste and provide a more reliable source of energy in areas with unreliable energy supply. Implementing smart energy solutions requires a combination of IoT devices, data analytics, and communication technologies [3]. However, the potential benefits of smart energy, including reduced energy consumption, increased efficiency, and minimized environmental impact, can have a significant impact on both individuals and communities [77].

#### *2.3. Smart Waste Management*

IoT applications leverage the power of the Internet of Things (IoT) to enhance waste management systems, making them more efficient, cost-effective, and environmentally friendly [78]. These applications utilize various IoT technologies to monitor, collect, analyze, and manage waste in real time [79]. Overall, smart waste management IoT applications offer a holistic approach to handling waste, promoting sustainability, reducing operational costs, and contributing to a cleaner environment. As IoT technology continues to evolve, these applications are likely to become even more advanced and widespread.
