Keywords

1 Introduction

Expansion of urban populations and the changing nature of urban governing concepts have both contributed to the desire for integrated and interoperable technologies that facilitate smart functioning of complex systems in cities. The creation of information and communication technology (ICT) and data services can provide many new services in a city, particularly in the developing world, resulting in a more productive, ecologically aware, and technological solution. Electricity and communication networks, which are critical for supplying urban services, are becoming more and more important. For higher-level services to function, the functionality, interoperability, and resilience of these networks are critical. Although utilities are being forced to upgrade and adapt their existing business scopes, methodologies, and system capabilities due to rapidly changing consumer behavior and technological development, several trends (such as distributed generation and electric vehicles) are significant. Due to the energy crisis, renewable energy capacity is of great interest today in future power generation [1]. The current energy crisis is leading to an increased interest in the future power generation capacity of renewable energy resources [2].

Between 2002 and 2030, fossil fuels generated the bulk of global primary energy consumption, compared to alternative renewable energy sources, which are less regarded as power generation sources as shown in Table 1. This results in a significant increase in CO2 emissions, causing severe ecological damage [4]. Renewable energy technologies as a cost-effective way to generate electricity in the future without emitting greenhouse gases [5]. The integration of renewable energy resources into smart grids is the focus of several current studies [6,7,8]. They discuss the advantages and disadvantages of renewable energy supplies as they are incorporated into an intelligent grid system [1]. Consequently, this article describes the effects of renewable energy on the smart grid.

Table 1 Defines the percentage of world primary energy demand from 2002 to 2030 [3]
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Harvesting energy from renewable resources, on the other hand, necessitates an valuable and sophisticated smart grid system [9]. Discussing more, smart grid can more effectively address difficulties including generated and raw energy losses, transmission losses, load optimization, and equal load distribution. Furthermore, distributed generation (DG) technologies help to manage demand and supply [10]. By increasing generation capacity through the introduction of RERs, the gap between supply and demand is reduced [11]. In the conventional power system, generating electricity faster than the rate of RERs can't be achieved within a short period of time. The following are the main benefits of renewable energy resources.

(a) less operating costs in different areas, (b) habitat for wildlife, (c) nature abundant, and (d) minimal maintenance cost is required [12]. Long-standing energy crises can be overcome with RERs. Maintaining energy growth should consider extending existing resources and expanding exploration [13]. We are motivated by the following to conduct this research: (a) A look at the main challenges and possible solutions to integrating renewable energy into the grid and (b) The technology minimizes the negative effects on the environment and reduces load on the non-renewable grid as well as usage of fossil fuels. Power generation, power distribution, and electricity pricing are proving to be inefficient under the traditional power grid [14, 15]. In spite of that, the demand for power is growing rapidly, with an increase of twice as much by 2050.

The benefits offered by SG are numerous, including the following

(a) Efficient performance, (b) Reduced cost for consumption, (c) Empowering consumers, (d) Easy-to-usetwo way system, (e) Communications infrastructure based on advanced technologies, and (f) intelligent control. There are frequent fluctuations in renewable energy, which introduces uncertainty to the system due to climate change [16]. An hour-by-hour forecast of the weather is the best solution to the issues outlined above [17]. Superconducting DC transmission lines can eliminate conversion losses in a DC-DC system. Briefly, the proposed study has the following major contribution: An overview of RER SG is provided, and its benefits are detailed. The barriers and challenges that must be overcome to move from a conventional power grid to a SG-based power grid are also reviewed in detail. In this work, we present comprehensive information on RERs technology as well as relevant factors that need to be evaluated in the context of SG integration, including how to evaluate RERs as assets. RER integration within SG is discussed in terms of its potential benefits and associated challenges. Furthermore, the integration of RERs within SG is also discussed from a financial and benefit perspective.

2 Smart Cities and Energy Applications

Controlling electricity flow is the function of SG. As SG is self-aware, it can adapt to changes in the network environment by automatically reconfiguring its settings based on the current conditions. As a matter of fact, at least in current times, the SG is only a solution to penetrate the conventional system with RERs. High-speed data acquisition and measurement have emerged with the introduction of new systems; SG will be able to operate in the future such as the one shown in Fig. 1. As SG is resilient and prognosis-focused, they are able to achieve high levels of success [12]. The SG is a conventional electricity distribution system that incorporates computer networking and intelligence [18]. Technology developed by SG includes automation as well. Power grids provide a variety of benefits through the concept of SG. It is important to deal with scheduling uncertainties, energy transfers between regions, reducing RERs, optimizing demand, distributing electric power, and forecasting to respond to emergencies. SG will benefit consumers by providing an interactive grid that facilitates the interaction with load management. This interface also provides the users with authentic and real-time pricing information and enables them to decide based on information.

Fig. 1
figure 1

Schematic of the smart grid [4]

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2.1 Smart Grid Benefits

As a result of SG, the following benefits occur:

(a) Metering using smart technology, (b) Renewable energy resources accommodation, (c) effectiveness, (d) encouraging, (e) possibilistic, (f) customer-centric, (g) strong, and (h) environment friendly, below we discuss each of them.

2.1.1 Smart Metering

The ability to exchange information on tariffs and power consumption in real-time is a unique feature of smart grid that makes use of communication systems.

2.1.2 Efficient

Increased end-user demand and the ability of the system to adapt without adding extra infrastructure.

We can use energy from any fuel source, including solar and wind, to the same extent that we can use natural gas and coal.

2.1.3 Quality-Focused

With no spikes, voltage drops, interruptions, or disturbances, we provide stable power.

2.1.4 Opportunistic

By leveraging plug-and-play novelty, it creates new markets and opportunities and capitalizes on them wherever and whenever appropriate.

2.1.5 Resilient

Decentralized power systems become more resilient to cyberattacks, severe faults, and disturbances as they are strengthened with SG security protocols.

2.1.6 Barriers

Even though SG’s viability is widely acknowledged, its implementation may take half a decade or more. Following is a list of factors contributing to the concept's unimplementation for over a decade:

2.1.7 Human Resource Development

There is no way to train the present staff to utilize and deploy the new technology. It will take time for the skills of the personnel to be developed, and a short-term solution may be needed in order to address the new requirement.

2.1.8 Financial Implications

It takes a lot of capital and operating expenses to replace an existing infrastructure with a new one. The government of developing countries offers incentives and rate-based funds to fund projects. Developing countries with a complex operating system do not see its expansion and modification as straightforward.

2.1.9 Project Planning

In order to ensure minimal disruption and to avoid disasters, it will take some time to implement SG as it replaces an existing operating system.

2.1.10 Legal and Regulatory

Regulation and legal organizations already in place can accommodate SG technology's benefits and costs. Before the deployment of the project, these issues need to be addressed properly.

2.1.11 Technical Issues

Defective analysis and unclear communication lead to different technical risks. SG technology and products have not been tested enough in the global marketplace due to its infancy, and there are no global solutions available that address SG technology and products.

2.1.12 Operations and Maintenance

The operation and maintenance of SG equipment will be different. It will also affect how current maintenance is implemented, making it easier to provide better components with better information and data.

2.1.13 Security and Privacy

The system has become increasingly dependent on technology. It will be possible to optimize the system with the collected information and data.

3 Grid Integration of Renewable Energy Resources

Our need for electrical energy is expected to rise in the future due to energy security, climate change, and sources of renewable energy. There are both dangers and opportunities associated with renewable energy. A system and its electrical characteristics will be much more challenging to run and regulate if there are more renewable sources linked to the grid. To improve urban energy supply and demand, the grid needs to make greater use of RERs. RERs and energy storage will continue to be used by the residential, commercial, and industrial sectors, despite their higher initial costs. They are influenced by factors such as independent power generation, sustainability, dependability, security, and power quality.

A smart grid can help reduce operating costs and increase efficiency on a wide range of levels. Smart grid technologies are, however, a benefit in that they enable an electricity network to feature high levels of renewable resources. Various types and scales of RER exist. There is geothermal energy, biomass energy, wind electricity, and hydro energy. However, when RERs are embedded in traditional power grids on a large scale, their benefits are greatly enhanced [18]. However, when RERs are embedded in traditional power grids on a large scale, their benefits are greatly enhanced [18]. As a result of SG approaches, renewable resources such as wind, solar, and geothermal can penetrate more readily. RERs penetrate SG in several ways as shown in Fig. 2. These are the characteristics of renewables derived from SGs.

Fig. 2
figure 2

Integration of renewable energies into the grid [19]

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  1. (1)

    Energy demand and supply are stabilized through SG technology. Various technologies can assist in this process. Distributed storage devices, advanced sensors, software to control markets, market signals, and information structures can all be utilized.

  2. (2)

    Automated SG technology uses feedback on distributed storage and demand to enhance the integration of RE generation hosting and allow for better and more cost-effective utilization.

  3. (3)

    RER penetration is restricted by the implementation of SG technologies.

  4. (4)

    A grid operator can coordinate the system and control it based on grid characteristics by applying SG technology relative to RE.

  5. (5)

    Software programs and converters and inverter devices are used to communicate, SGs provide diverse management and distribution mechanisms for RE.

For the SG, model evaluations of technologies and resources for renewable energy such as biomass, solar, wind, and fuel cells are necessary, as well as control evaluations of their penetration levels and effect on innovation and upgradation. Biological resources are non-RE resources because they cannot be replicated at comparable scales. Nuclear energy, Coal, petroleum, gas, and oil are among the major non-RE sources of energy. A safe and reliable energy supply is largely responsible for financial growth, computerization, and modernization. There is a constant increase in power demand. There is an urgent need for energy right now around the world. Power demands are met by using fossil fuels as primary energy sources. Hazardous gases are mainly emitted by fossil fuels. According to the CO2 distribution in 2013, oil accounted for 33% of the emissions, gas flares made up 0.6%, coal accounted for 43%, cement made up 5.3%, and gas accounted for 18% [19].

  1. A.

    RERs Taxonomy

Energy is derived primarily from the sun. With all the other renewable energy sources like Sun-dependent energy sources, such as wind and hydro, humanity can be supplied with energy for almost a billion years. As predicted, at this point liquid water will not be possible on Earth due to the earth's increasing temperature [18]. Figure 3 shows how the potential sources of electricity from renewable sources are further categorized.

Fig. 3
figure 3

Types of RER

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In the context of smart grids, integrated renewable energy resources refer to the process by which power is transferred from renewable energy to various network technologies [20]. Figure 1 illustrates the basic architecture of an AC grid that integrates renewable energy [20].

Figure 4 illustrates the design of the overall system:

  • Solar and wind power plants (renewable energy sources) can be inputs into the AC grid.

    Fig. 4
    figure 4

    AC grids designed to integrate renewable energy

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  • Substations: AC power from the plants is considered as a distribution type of power.

  • Transmission lines: The AC power they deliver to the distribution system is either high voltage or low voltage.

Integrating RE into conventional power plants is meant to reduce the environmental impact of conventional power plants [21]. The SG [22] maintains this reduction properly. Also, by developing a method of interconnecting renewable energy supplies with the main grid, grid operators can develop a more efficient system [23].

Integrated renewable energy sources require a control system, as shown in Fig. 5, that is capable of many different functions at the standalone application level:

Fig. 5
figure 5

An integrated system for generating renewable energy

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  • Communicate between the various components of the system and maintain information.

  • Renewable energy output can be adjusted.

  • Create the signals that will signal the damp loads and the storage subsystems in operation.

  • Overcharging must be avoided and storage must be operated within the prescribed limits.

Renewable energy sources can provide a number of benefits. That is why their introduction into smart grids is becoming a very hot topic of research [24, 25]. Furthermore, the literature shows that the integration of renewable energy resources into smart grid presents a set of benefits and challenges:

A renewable energy resources are advantageous in a grid system, and they can be summarized as follows:

  • Positive environmental aspects include the following: The addition of renewable energy sources to the grid system makes fossil-fuel power plants produce less electricity and, thus, reduce CO2 emissions.

  • Social benefit: The ability to sell excess energy to utilities when many people isolate their own energy source is one of the benefits of isolating one's own energy source.

  • Economic benefit: Jobs are created as a result of integrated renewable energy.

4 Challenging Issues of Renewable Sources Within SG

Grid stability, power quality, and load on the network are threatened by the inclusion of DG. Controlling DG appropriately can solve the problems mentioned above [21]. Achieving an extra-efficient power grid will require an advanced grid with communication technologies and controlled services.

Comparative analysis of renewables and non-RE resources.

 

Renewable

Non-renewable

Availability

1. Sun, wind, geothermal, and ocean energy are available in ample amount

2. Available everywhere

3.no cost

4. Reusable

1. Area specific

2. Limit restriction

3. Cannot be used more than once

4. Destine to expire one day

Environmental effect

1. Less CO2 emission

2. No environmental harm

3. Clean energy production

1. Huge amount of toxic gas discharge

2. Causes great damage to environment

3. After production environmental

effects are very dangerous to humans

Economical effect

1. Low-cost production makes it more economical

2. Employment development

1. Plant Set up is less expensive than production

2. High raw fuel charges

3. High transportation charges

Advantages

1. Environmentally friendly

2. More Economical

3. Stabilized energy prices

1. Quite easy to use

2. Market value is more

3. Cost effective

Disadvantages

1. More capital cost

2. Huge area required for set up

3. Large quantity generation is difficult

1. Fuel price hike is very frequent

2. Great environmental hazards

3. Acid rain

Issues associated with RER integration.

  1. (1)

    Harmonics

    The main cause of harmonics in power systems is the operation of power electronics. As a result of deploying power electronics devices in greater quantities, voltage surges have occurred. Because of DG systems equipped with converters and inverters, such as wind and solar power, the transmission grid can face a high harmonic level. Standards must account for voltage harmonics and nonlinear behavior if they are to properly assess harmonics.

  2. (2)

    Transients

    Lightening as well as connecting and disconnecting generation from the grid are the leading causes of transients. Additionally, if huge flows of current are allowed, transients can result. It is possible to regulate such currents to a certain extent by designing generators in a prudent manner. Power supply stability can be weakened by transients tripping overvoltage protection devices.

  3. (3)

    Forecasting

    Forecasting accurately solar and wind energy production can reduce grid integration costs and ease the challenges of operating a grid with renewable energy resources. There is a lot of research being done in the field of wind energy forecasting. An un-stationary stochastic process produces wind power. There are two major approaches to tackling this problem:

    1. (a)

      Wind farm output is predicted using a practical approach that combines wind farm physical model and data collection from weather predictions

    2. (b)

      There are many methods of matching patterns, such as statistical forecasting, fuzzy systems, neural networks, and ARMA, etc., combined with weather prediction methods to forecast the output of a wind farm are some of the techniques that are used.

  4. (4)

    Power Grid Stability

    Wind power penetration level exceeding 15% constitutes a serious systemic problem, especially in island-based power systems. When several integrated power generation sources are integrated, analyzing system performance and stability can be a serious and difficult task. The overall impact of fluctuation in RE production on frequency and voltage is determined by

    (a) A generation control system that is automated, (b) load forecasting, (c) Response to transient frequency changes, and (d) Responses to adaptation.

5 Conclusion and Future Work

SG systems could be a useful method of meeting future energy requirements as they are highly efficient and effective. In addition to providing significant benefits to the environment, SG can also conserve non-renewable resources. As a result of its immense benefits, RER's integration within SG is extremely important. Among the top concerns that need to be addressed are renewable energy's highly variable nature, uncertainty, and intermittency. A significant challenge and an exciting research area is the integration of RERs into the conventional grid. Control methodologies will be needed for many of these issues. As well as SG basics and renewables, we present some specific problems caused by the uncertain, volatile nature of REERs. Making energy resources efficient, reliable, and affordable is a daunting task. Indirectly and directly, RE sources can have an impact on the environment and the economy. Energy security could be improved with RERs power generation inside SG. Politicians must encourage RERs as a means of ensuring non-carbon and sustainable energy. Service providers are experiencing a major shift with SG. The effective and efficient penetration of renewables within SG will require different approaches in order to reap maximum benefits. Utilities need strategies to handle this disruptive technological shift. For SG technologies to become able to contribute to new business processes and penetrate renewable energy resources, technology needs to be upgraded.

A number of benefits and challenges are outlined in this article regarding renewable energy integration in smart grids. Suitable control strategies, such as converter and grid controls, are essential to an efficient renewable energy integration. Integrated RERs systems-dependent power production is the future goal of this work.