Analysis of Impacts in Electric Power Grids Due to the Integration of Distributed Energy Resources

Abstract

In the present article, the impacts that arise in electrical grids due to the integration of distributed energy resources (DER) are identified and analyzed, aiming to provide a basis from which the effects of these new technologies can be considered. To conduct this research, information was collected and analyzed, which was classified according to each of the impacts evidenced in the literature, such as technical, economic, social, environmental, sectoral, and political. Considering the classification of impacts by category, the corresponding advantages and disadvantages were highlighted, and based on this, a qualitative evaluation of the information found was conducted along with respective analyses. Thus, based on the development of this article, it can be concluded that DER influences many aspects, and according to the qualitative evaluation, clarity is provided regarding the contribution of each impact within electrical grids. It was found that, out of 100% of the impacts identified, those with the highest percentage of contribution are the technical impacts.

1. Introduction

The traditional structure of an electrical system consists of large-scale electricity generation and transmission systems, through which large energy blocks are transported to distribution systems. This structure was presented as a conventional solution for delivering energy due to demographic growth and the demand for goods and services. Therefore, the system operates with unidirectional flows, and the end user plays a passive role in the energy supply chain [1,2].

The technological evolution, industrialization, and electrification opened the doors for the traditional structure to transform, allowing the use of new processes for energy production and consumption through the implementation of new technologies. Likewise, the transformation of the electrical sector is based on the factors of decarbonization, decentralization, democratization, digitalization, and diversification, better known as the Five Ds of the global energy transition [1,2,3].

The Five Ds are fundamental in enabling the adoption of new technologies, as they represent great challenges in the current conventional electrical grids. This is because new technologies bring with them bidirectional flows and the possibility of greater access to energy through the use of available resources without the need for an interconnected system. They also allow connectivity between users, who can play a more active role in the supply chain and the system [1,3,4,5].

Taking this into account, it is very important to consider distributed energy resources, as they are an emerging technology that diversifies the electrical system. Through them, it is possible to have access to small-scale energy generation using available resources near the end user and providing different services. For this reason, it is necessary to review the impacts of the integration of distributed energy resources on electric grids, qualitatively identifying their impact and relevance [1,2,6,7,8].

Therefore, this article is divided into seven sections, including the introduction. In Section 2, distributed energy resources are contextualized, and in the Section 3, the impacts found in the literature regarding the integration of this technology are presented. Section 4 and Section 5 address the advantages and disadvantages of the mentioned impacts and the qualitative evaluation conducted with the respective analyses, respectively. Finally, Section 6 contains the discussion of the study and Section 7 presents the conclusions drawn from the research.

The contributions presented by this review are as follows:

• Based on the research carried out to obtain the general impacts on the electrical system, six different types were catalogued, which were technical, environmental, economic, social, political and sectoral;
• With the results obtained in this article, emerging and driving themes for potential future research work are identified related to the impacts on power grids due to the integration of distributed energy resources;
• The contribution of each impact within the electrical system when integrating DER. From this, it can be concluded that within the 100%, the impacts that make the highest percentage of contribution are the technical impacts.

2. Distributed Energy Resources

Distributed energy resources, better known as DER, are those resources located near the end user or directly connected to the distribution grid, as they operate on a small or medium scale. DER can inject energy into the grid, consume energy, or provide other services. In this regard, among the resources that make up DER, we can cite primary sources dedicated to self-generation and distributed generation, energy storage, electric vehicles, and demand response, as shown in Figure 1 [1,9].

It is important to note that the inclusion of DER in the power electric system opens up the possibility for an energy transformation, as it allows the use of new technologies for energy supply to the electrical system. In line with this, it is important to briefly mention these resources [1,2].

Distributed generation, also known by its acronym DG, is a concept that does not have a single globally accepted definition. However, when referring to this type of generation, it generally means small-scale energy generation that connects to the end user’s facilities and to the electrical distribution system. It is characterized by the use of non-conventional renewable energy sources, modular systems, flexibility in operation, and ease of maintenance and repair [1,9,10].

On the other hand, there is also demand response, often referred to by its acronym DR. This can be considered a set of mechanisms by which electricity prices can be evaluated, helping to avoid high prices due to load fluctuations. Lastly, electric vehicles (EV) have experienced a surge in recent times; they require energy to function, behaving as a load on the system.

3. Impacts Due to DER Aggregation

Around the world, the adoption of distributed energy resources (DER) is increasing, and they have gained significant relevance in recent years, as their use promotes the reduction in greenhouse gas emissions into the atmosphere, the decentralization of energy generation, as well as the creation of new business models across the entire electrical sector, the mass adoption of prosumers, and the inclusion of technologies such as demand response (DR) for use by end users [11]. In this sense, some countries have implemented different strategies to promote greater DER integration into their electrical systems [10].

Given the above, the transition of electrical systems is essential to achieve the integration of new technologies such as DER [12]. In this regard, an electrical system generally involves various aspects when carrying out the entire process of generation, transmission, and the distribution of energy to the end user. Therefore, based on the scientific literature, it is possible to identify the impacts shown in Figure 2.

For an adequate interpretation of the information that has been consolidated for each different type of impact on the electrical system due to the integration of DER, it has been organized in the form of tables following, for each type of impact, the order presented in Figure 2, as follows. In Table 1, Table 2, Table 3, Table 4, Table 5 and Table 6, the cases of different impacts, evidenced in scientific publications, are specified using “impact 1”, “impact 2”, etc. In Table 7, Table 8, Table 9, Table 10, Table 11 and Table 12, a brief summary is presented for each advantage and disadvantage of integrating DER into the electrical system. An adequate interpretation of the information presented in Table 13, which is indicated in front of the “impact” column, is directly related to the information presented in Table 1, Table 2, Table 3, Table 4, Table 5 and Table 6 for the different cases of impacts that were classified.

3.1. Technical Impacts

Technical impacts are understood as those effects that come with the inclusion of DER in the operations of electric networks [11]. This impact is due to the fact that DER introduces new devices to the electric power system, which bring with them new operational demands, mainly in the distribution networks, since it is mainly in this area where these resources have greater connection [12,13]. Table 1 shows the technical impacts of DER integration.

Table 1. Technical impacts.

Classification	Impact 1	Impact 2	Impact 3	Impact 4	Impact 5	Impact 6	Impact 7	References
Power quality	Overvoltage on transmission lines and transformers	Current harmonics in the network	Flicker due to the integration of renewable energies	Increase in demand for EVs	The use of voltage support control in DERs	Real-time compensation of estimated disturbances		[10,14,15,16,17,18,19,20,21,22,23]
Stability	Unexpected tension operations	Lack of inertia	Limited contribution to fault current	Voltage and frequency deviations	Transient stability evaluations are more limiting than steady-state analysis	Impacts by cyberattacks on power system stability	Grid stability support	[10,12,16,17,19,20,21,22,23,24,25,26,27,28,29,30]
Protections	Bidirectional flows	Change in current level across a fault	Blinding of protection	False shots	Lack of coordination in the operation of automatic reclosers	Adaptive protections		[12,15,19,23,31,32,33]
Cybersecurity	Greater number of devices connected to the network	Use of conventional technologies	Identify and design the architectures necessary for a distributed system	Network vulnerability due to decentralization	Increasing vulnerability to attacks due to the distributed nature and network connectivity of DER			[11,22,23,24,30]
Reliability	Reliable supply of energy service	Resilience is added to the system	Adaptive resilience metrics can de-rate resilience due to uncertainties	Perform key grid stability functions by providing ancillary services	Increases with an adequate energy generation control system			[12,17,18,19,20,22,24,26,28,29,30,34,35,36,37,38,39,40,41,42,43,44,45]

Table 1. Technical impacts.

Classification	Impact 1	Impact 2	Impact 3	Impact 4	Impact 5	Impact 6	Impact 7	References
Power quality	Overvoltage on transmission lines and transformers	Current harmonics in the network	Flicker due to the integration of renewable energies	Increase in demand for EVs	The use of voltage support control in DERs	Real-time compensation of estimated disturbances		[10,14,15,16,17,18,19,20,21,22,23]
Stability	Unexpected tension operations	Lack of inertia	Limited contribution to fault current	Voltage and frequency deviations	Transient stability evaluations are more limiting than steady-state analysis	Impacts by cyberattacks on power system stability	Grid stability support	[10,12,16,17,19,20,21,22,23,24,25,26,27,28,29,30]
Protections	Bidirectional flows	Change in current level across a fault	Blinding of protection	False shots	Lack of coordination in the operation of automatic reclosers	Adaptive protections		[12,15,19,23,31,32,33]
Cybersecurity	Greater number of devices connected to the network	Use of conventional technologies	Identify and design the architectures necessary for a distributed system	Network vulnerability due to decentralization	Increasing vulnerability to attacks due to the distributed nature and network connectivity of DER			[11,22,23,24,30]
Reliability	Reliable supply of energy service	Resilience is added to the system	Adaptive resilience metrics can de-rate resilience due to uncertainties	Perform key grid stability functions by providing ancillary services	Increases with an adequate energy generation control system			[12,17,18,19,20,22,24,26,28,29,30,34,35,36,37,38,39,40,41,42,43,44,45]

3.2. Environmental Impacts

New DER technologies seek to mitigate greenhouse gas (GHG) emissions when integrated into electrical grids. In this sense, it is of great importance to establish the environmental impacts brought about by these resources, through which the substitution of non-renewable and polluting energy sources is sought [34,46]. Therefore, considering the information found, Table 2 is presented to consolidate the environmental impacts present in the scientific literature [1].

Table 2. Environmental impacts.

Classification	Impact 1	Impact 2	Impact 3	Impact 4	References
Greenhouse gases	Decrease in the use of fossil fuels for energy generation	Primary production of aluminum from bauxite processing	CO2 reduction	Using DR programs	[21,22,25,27,28,29,30,37,41,42,43,47,48,49,50,51]
Renewable resource	Achieve savings in diesel fuel due to the optimization of functional generators with fossil fuels	Contribution to the energy matrix of each country	Installation of DER as part of the expansion strategy and assessment	Substation automation and control increase renewable penetration	[19,20,22,23,25,28,29,30,34,35,36,37,38,40,42,44,45,47,49,52]
Investigation	Research into new energy sources with minimal environmental impacts				[35,36,39,41,52]
Flora and Fauna	Implementation of infrastructure in the ecosystem	Preservation of the different species according to the established guidelines	Felling of balsa trees for the construction of wind turbine blades		[34,49,52,53]

Table 2. Environmental impacts.

Classification	Impact 1	Impact 2	Impact 3	Impact 4	References
Greenhouse gases	Decrease in the use of fossil fuels for energy generation	Primary production of aluminum from bauxite processing	CO2 reduction	Using DR programs	[21,22,25,27,28,29,30,37,41,42,43,47,48,49,50,51]
Renewable resource	Achieve savings in diesel fuel due to the optimization of functional generators with fossil fuels	Contribution to the energy matrix of each country	Installation of DER as part of the expansion strategy and assessment	Substation automation and control increase renewable penetration	[19,20,22,23,25,28,29,30,34,35,36,37,38,40,42,44,45,47,49,52]
Investigation	Research into new energy sources with minimal environmental impacts				[35,36,39,41,52]
Flora and Fauna	Implementation of infrastructure in the ecosystem	Preservation of the different species according to the established guidelines	Felling of balsa trees for the construction of wind turbine blades		[34,49,52,53]

3.3. Economic Impacts

Through energy transition, new business opportunities are created, as well as opportunities for the production and consumption of electric energy [5]. In this sense, it is important to look at the economic issue and how it changes as the different types of DER are integrated into the system. Therefore, Table 3 presents the technical impacts seen with DER integration [1].

Table 3. Economic impacts.

Classification	Impact 1	Impact 2	Impact 3	Impact 4	Impact 5	Impact 6	References
New markets	Wholesale markets	Energy sales	Sustainable mobility	Intraday market	Transactional dynamics		[37,38,54,55,56]
Network operators	Administration to promote free competition	Ensure GD connection as long as there are no technical limitations	DSO	Savings in investment and maintenance costs	The models help DSO plan and manage grid expansion and DER integration		[12,16,20,21,22,23,24,25,28,29,30,34,36,37,39,40,41,42,43,44,45,57,58,59,60,61]
Energy marketing	Future sale of energy as the value of the surplus is not paid	Sale of surplus to other users	Competitive market promotion				[11,34,57,58,59]
Prosumers	Informed decision-making	Participation in DR programs	Boosting the use of AMI	DER energy generation above legal limits			[21,37,44,47,62,63]
Benefits	Discount on income tax	Exclusion of VAT for those who develop efficient energy management projects	Using EVs to avoid conventional mobility restrictions	Balances demand growth and wildfire risk mitigation	Aggregates all electric system benefits and relevant environmental externalities	The price/quantity curve can be an effective way to offer unused capacity	[16,17,18,20,21,22,24,26,27,28,29,30,33,36,37,40,41,42,43,45,47]

Table 3. Economic impacts.

Classification	Impact 1	Impact 2	Impact 3	Impact 4	Impact 5	Impact 6	References
New markets	Wholesale markets	Energy sales	Sustainable mobility	Intraday market	Transactional dynamics		[37,38,54,55,56]
Network operators	Administration to promote free competition	Ensure GD connection as long as there are no technical limitations	DSO	Savings in investment and maintenance costs	The models help DSO plan and manage grid expansion and DER integration		[12,16,20,21,22,23,24,25,28,29,30,34,36,37,39,40,41,42,43,44,45,57,58,59,60,61]
Energy marketing	Future sale of energy as the value of the surplus is not paid	Sale of surplus to other users	Competitive market promotion				[11,34,57,58,59]
Prosumers	Informed decision-making	Participation in DR programs	Boosting the use of AMI	DER energy generation above legal limits			[21,37,44,47,62,63]
Benefits	Discount on income tax	Exclusion of VAT for those who develop efficient energy management projects	Using EVs to avoid conventional mobility restrictions	Balances demand growth and wildfire risk mitigation	Aggregates all electric system benefits and relevant environmental externalities	The price/quantity curve can be an effective way to offer unused capacity	[16,17,18,20,21,22,24,26,27,28,29,30,33,36,37,40,41,42,43,45,47]

3.4. Social Impacts

It is very important to consider the impacts that DER implementation has on society, because, as it is an emerging technology, training to aid in research and training in areas of the development of new sources and uses of energy must be encouraged [5]. Table 4 compiles the social impacts found in the literature [1].

Table 4. Social impacts.

Classification	Impact 1	Impact 2	Impact 3	References
Investigation	Acquire new knowledge	Achieve innovation and thus strengthen human capital	Contributes to research on resilient grid expansion	[34,35,36,41,42,45,47]
Opportunities	Educational opportunities	Human capital formation	Job opportunities from manufacturing, construction and installation to operation and maintenance	[21,34,36,45,47,49]
Restrictions	Deficit of trained human capital	Difficult access to the ZNI	Balances power shut-offs and grid expansion	[34,36,46,63]
Non-interconnected areas	Energy supply using own resources	Stimulating the economy of remote regions	Improve the quality of life of some communities	[59,64]

Table 4. Social impacts.

Classification	Impact 1	Impact 2	Impact 3	References
Investigation	Acquire new knowledge	Achieve innovation and thus strengthen human capital	Contributes to research on resilient grid expansion	[34,35,36,41,42,45,47]
Opportunities	Educational opportunities	Human capital formation	Job opportunities from manufacturing, construction and installation to operation and maintenance	[21,34,36,45,47,49]
Restrictions	Deficit of trained human capital	Difficult access to the ZNI	Balances power shut-offs and grid expansion	[34,36,46,63]
Non-interconnected areas	Energy supply using own resources	Stimulating the economy of remote regions	Improve the quality of life of some communities	[59,64]

3.5. Political Impacts

For this specific impact, the Colombian electrical system and the different actions that have been carried out in terms of policy to allow the incorporation of DER will be considered. In this sense, the PEN 2020-2050 seeks to encourage public policy towards the adoption of new technologies, through which an efficient use of resources is obtained and an environment with a competitive market that promotes the country’s economy is achieved [5].

In accordance with the above, the energy policy guidelines issued by the MME, as well as the regulations of the CREG and the UPME, and the CNO agreements, among other entities that are part of the Colombian government, must be considered. The definition given by the Ministry in [9] is the basis for the implementation of DER, from which the different types of DER connected to the national electrical system can be established [1].

Considering the above, Table 5 presents the different changes in the Colombian regulatory framework from 2014 to 2030 to summarize the information found.

Table 5. Political impacts.

Classification	Impact	Description	References
Incentives	Law 1715 of 2014	Discount on income tax, exclusion of goods and services from VAT, accelerated depreciation and exemption from customs duties.	[38,47,55,65]
	Law 1964 of 2019	Promote the use of EVs for sustainable mobility and reducing the emissions of GHG and pollutants into the atmosphere
Laws	Law 143 of 1994	It has been modified to allow the sale of surpluses from wind turbines, under certain criteria	[31]
Regulations	RETIE draft 2022	The aim is to establish the installation requirements, connection to the system, necessary protections and the viability of the DER connection	[66,67]
	NERC Standard, CIP-014-1	The standard aims to identify and protect transmission stations and substations, as well as their primary control centers	[19]
Resolutions	Resolution 281 of 2015	Defines the maximum power limit for small-scale self-generation	[57,68,69,70,71,72,73,74,75,76,77,78,79]
	Resolution 024 of 2015	Self-generation activity is regulated in the SIN
	Resolution 40072 of 2018	Through which the mechanisms for implementing AMI in the public energy service are established
	Resolution 019 of 2018	The rights of small-scale wind turbine users are established
	Resolution 030 of 2018	Regulation of self-generation and DG activities in the SIN
	Resolution 40807 of 2018	Adoption of a comprehensive plan on climate change in the mining and energy sector.
	Resolution 060 of 2019	Allow the connection and operation of photovoltaic solar and wind plants in the SIN
	Resolution 137 of 2020	Definition of the general tariff for the remuneration of the energy service through individual solar photovoltaic solutions
	Resolution 170 of 2020	Allow the connection and operation of solar photovoltaic and wind plants in the SDL equal to or greater than 5 MW
	Resolution 173 of 2021	Allow the connection and operation of photovoltaic solar and wind plants in the SDL greater than 1 MW and less than 5 MW
	Resolution 174 of 2021	Regulation of small-scale self-generation and DG activities in the SIN
	Resolution 148 of 2021	Allow the connection and operation of photovoltaic solar and wind plants in the SDL equal to or greater than 5 MW
Decrees	Decree 348 of 2017	Public policy guidelines are established for the efficient management of energy and the delivery of small-scale self-generation surpluses	[80]
Studies	Smart grid vision 2030—UPME	Studies carried out on the roadmap for the implementation of smart grids in Colombia	[81]

Table 5. Political impacts.

Classification	Impact	Description	References
Incentives	Law 1715 of 2014	Discount on income tax, exclusion of goods and services from VAT, accelerated depreciation and exemption from customs duties.	[38,47,55,65]
	Law 1964 of 2019	Promote the use of EVs for sustainable mobility and reducing the emissions of GHG and pollutants into the atmosphere
Laws	Law 143 of 1994	It has been modified to allow the sale of surpluses from wind turbines, under certain criteria	[31]
Regulations	RETIE draft 2022	The aim is to establish the installation requirements, connection to the system, necessary protections and the viability of the DER connection	[66,67]
	NERC Standard, CIP-014-1	The standard aims to identify and protect transmission stations and substations, as well as their primary control centers	[19]
Resolutions	Resolution 281 of 2015	Defines the maximum power limit for small-scale self-generation	[57,68,69,70,71,72,73,74,75,76,77,78,79]
	Resolution 024 of 2015	Self-generation activity is regulated in the SIN
	Resolution 40072 of 2018	Through which the mechanisms for implementing AMI in the public energy service are established
	Resolution 019 of 2018	The rights of small-scale wind turbine users are established
	Resolution 030 of 2018	Regulation of self-generation and DG activities in the SIN
	Resolution 40807 of 2018	Adoption of a comprehensive plan on climate change in the mining and energy sector.
	Resolution 060 of 2019	Allow the connection and operation of photovoltaic solar and wind plants in the SIN
	Resolution 137 of 2020	Definition of the general tariff for the remuneration of the energy service through individual solar photovoltaic solutions
	Resolution 170 of 2020	Allow the connection and operation of solar photovoltaic and wind plants in the SDL equal to or greater than 5 MW
	Resolution 173 of 2021	Allow the connection and operation of photovoltaic solar and wind plants in the SDL greater than 1 MW and less than 5 MW
	Resolution 174 of 2021	Regulation of small-scale self-generation and DG activities in the SIN
	Resolution 148 of 2021	Allow the connection and operation of photovoltaic solar and wind plants in the SDL equal to or greater than 5 MW
Decrees	Decree 348 of 2017	Public policy guidelines are established for the efficient management of energy and the delivery of small-scale self-generation surpluses	[80]
Studies	Smart grid vision 2030—UPME	Studies carried out on the roadmap for the implementation of smart grids in Colombia	[81]

3.6. Sectorial Impacts

As the transformation of the electricity sector is carried out, traditional planning and the operation of networks must be included, since new actors, such as DER in this case, must be included for the correct operation of the system. To do this, the system must evolve in accordance with its needs to meet the demand for energy, in accordance with the technical, economic and environmental conditions [1,5,60,82]. Therefore, Table 6 summarizes the sectoral impacts found.

Table 6. Sectoral impacts.

Classification	Impact 1	Impact 2	Impact 3	Impact 4	References
Decentralization	Changes in the structure of TSO and DSO	Modification in the planning and operation of networks	Adaptation to the regulatory framework of each country	Ensure and facilitate interaction between ORs and users with DER	[19,21,22,23,26,27,28,29,30,33,37,40,41,42,43,45,61,64,83,84]
Integration	Union of academia, government and industry	Complementary areas of knowledge; electrical, electronic, communications and systems	Improvement of the grid and energy transition	Vehicle-to-Grid (V2G) technology	[18,19,21,22,23,26,27,28,29,30,33,36,37,38,40,41,42,43,45,85]

Table 6. Sectoral impacts.

Classification	Impact 1	Impact 2	Impact 3	Impact 4	References
Decentralization	Changes in the structure of TSO and DSO	Modification in the planning and operation of networks	Adaptation to the regulatory framework of each country	Ensure and facilitate interaction between ORs and users with DER	[19,21,22,23,26,27,28,29,30,33,37,40,41,42,43,45,61,64,83,84]
Integration	Union of academia, government and industry	Complementary areas of knowledge; electrical, electronic, communications and systems	Improvement of the grid and energy transition	Vehicle-to-Grid (V2G) technology	[18,19,21,22,23,26,27,28,29,30,33,36,37,38,40,41,42,43,45,85]

4. Advantages and Disadvantages of the Impacts of DER Integration

Now, in accordance with the definition of the technical, environmental, economic, social, political and sectoral impacts that occur in the electric power system as evidenced in the previous section, it is important to describe the advantages and disadvantages of these. Therefore, the following tables compile the information according to the impacts evidenced in the previous section [1].

Table 7 shows the advantages and disadvantages corresponding to the technical impacts present in Table 1.

Table 7. Advantages and disadvantages of technical impacts.

Classification	Impact	Advantages	Disadvantages
Power quality	1	Network simulations to establish how DER integration affects the grid and to what extent it does so [10].	It is related to issues of equity and energy quality [12]. The useful life of transformers is reduced [12]. The limits set by the DSO for an overvoltage are broken [12]. Overvoltages have a greater magnitude near the photovoltaic installation and can cause equipment damage [12]. Operation at the thermal limits of overhead lines and transformers [86].
	2	The harmonics generated by the DER input have a limit, whereby they can only generate 5% distortion of the current signal [14].	In the case of GD through photovoltaic solar energy, there is signal distortion due to the low power that reaches the inverter [10,87].
	3	For overvoltages, harmonics and flicker, energy storage systems can be used since they allow for improving energy quality by mitigating these effects due to the deterioration of public services [88].	Intermittent nature of some DG such as photovoltaic energy [12].
	4		Network congestion problems [10].
Stability	1		Voltage imbalance and regulation [10]. They occur due to changes in power injection by GD [10,12]. They can cause damage to equipment [12].
	2		The total inertia of the system decreases as there is a greater introduction of renewable energy sources such as solar and wind [89]. The lack of inertia results in large variations in frequency, and therefore affects the integrity of the network [89]. If the variations in frequency are very large, there may be unwanted triggering of the protections, disconnection of generation or load units and instability [89].
	3		The functioning of the protection systems may be compromised [86]. Suffer failures due to the use of conventional protection devices, i.e., not suitable for including DER [86].
	4		It is affected by DG fluctuations, especially those based on renewable energies [10]. Incorrect operations of power converters, load and protection are obtained [10].
Protections	1		Use of unidirectional and conventional protective equipment [12,88]. Protection schemes cannot adequately stop a failure, and possibly take other uninvolved areas out of service [88]. They cause damage to equipment such as lines, transformers and switches and, therefore, there are higher costs for the replacement of this equipment [88].
	2		It depends on the capacity of the GD, and the greater its contribution, the more directly it affects the sensitivity of the system and therefore the reliability of its protection [86,90].
	3		The short circuit is not detected because the current contribution from the network is not sufficient to trigger the protection [86].
	4	They can be avoided by proper relay adjustment, i.e., by increasing the fault clearing time [90].	The security of the protection systems is affected [86].
	5		They are most common in networks with airlines [86]. Connecting GD contributes to the current in a fault, and therefore affects detection by the recloser [90]. The selectivity of the protection system is affected [90].
	6	They are presented as a technique to improve protection schemes [12].	They require additional communication links and therefore a higher cost [12].
Cybersecurity	1	Ensure efficient, safe and reliable operation to maintain established quality and safety levels [11].	Vulnerability to cyber threats is introduced [11].
	2	The gaps that exist between the technologies used must be studied [11].
	3	To provide a resilient attack surface, have vulnerability ratings, and assist in design principles for utilities and consumers as more DERs are adopted [11].
	4		The attack surface is increased by having DER connected to different points [11]. Information is no longer concentrated in network operators, as administrative borders must be crossed, which puts it at risk of attacks [11].
Reliability	1	Guarantee quality and reliability conditions of the energy service [34]. DER helps maintain power service under extreme conditions [88].	It is affected when the GD input changes the sensitivity of the protections [86].
	2	Adaptability of the system to changes or disturbances [34]. It allows the entry of new technologies and thus the diversification of the energy matrix [34]. A series of studies have been aimed at increasing resilience to potential threats [91]. DER contributes to improving resilience in distribution systems [88].

Table 7. Advantages and disadvantages of technical impacts.

Classification	Impact	Advantages	Disadvantages
Power quality	1	Network simulations to establish how DER integration affects the grid and to what extent it does so [10].	It is related to issues of equity and energy quality [12]. The useful life of transformers is reduced [12]. The limits set by the DSO for an overvoltage are broken [12]. Overvoltages have a greater magnitude near the photovoltaic installation and can cause equipment damage [12]. Operation at the thermal limits of overhead lines and transformers [86].
	2	The harmonics generated by the DER input have a limit, whereby they can only generate 5% distortion of the current signal [14].	In the case of GD through photovoltaic solar energy, there is signal distortion due to the low power that reaches the inverter [10,87].
	3	For overvoltages, harmonics and flicker, energy storage systems can be used since they allow for improving energy quality by mitigating these effects due to the deterioration of public services [88].	Intermittent nature of some DG such as photovoltaic energy [12].
	4		Network congestion problems [10].
Stability	1		Voltage imbalance and regulation [10]. They occur due to changes in power injection by GD [10,12]. They can cause damage to equipment [12].
	2		The total inertia of the system decreases as there is a greater introduction of renewable energy sources such as solar and wind [89]. The lack of inertia results in large variations in frequency, and therefore affects the integrity of the network [89]. If the variations in frequency are very large, there may be unwanted triggering of the protections, disconnection of generation or load units and instability [89].
	3		The functioning of the protection systems may be compromised [86]. Suffer failures due to the use of conventional protection devices, i.e., not suitable for including DER [86].
	4		It is affected by DG fluctuations, especially those based on renewable energies [10]. Incorrect operations of power converters, load and protection are obtained [10].
Protections	1		Use of unidirectional and conventional protective equipment [12,88]. Protection schemes cannot adequately stop a failure, and possibly take other uninvolved areas out of service [88]. They cause damage to equipment such as lines, transformers and switches and, therefore, there are higher costs for the replacement of this equipment [88].
	2		It depends on the capacity of the GD, and the greater its contribution, the more directly it affects the sensitivity of the system and therefore the reliability of its protection [86,90].
	3		The short circuit is not detected because the current contribution from the network is not sufficient to trigger the protection [86].
	4	They can be avoided by proper relay adjustment, i.e., by increasing the fault clearing time [90].	The security of the protection systems is affected [86].
	5		They are most common in networks with airlines [86]. Connecting GD contributes to the current in a fault, and therefore affects detection by the recloser [90]. The selectivity of the protection system is affected [90].
	6	They are presented as a technique to improve protection schemes [12].	They require additional communication links and therefore a higher cost [12].
Cybersecurity	1	Ensure efficient, safe and reliable operation to maintain established quality and safety levels [11].	Vulnerability to cyber threats is introduced [11].
	2	The gaps that exist between the technologies used must be studied [11].
	3	To provide a resilient attack surface, have vulnerability ratings, and assist in design principles for utilities and consumers as more DERs are adopted [11].
	4		The attack surface is increased by having DER connected to different points [11]. Information is no longer concentrated in network operators, as administrative borders must be crossed, which puts it at risk of attacks [11].
Reliability	1	Guarantee quality and reliability conditions of the energy service [34]. DER helps maintain power service under extreme conditions [88].	It is affected when the GD input changes the sensitivity of the protections [86].
	2	Adaptability of the system to changes or disturbances [34]. It allows the entry of new technologies and thus the diversification of the energy matrix [34]. A series of studies have been aimed at increasing resilience to potential threats [91]. DER contributes to improving resilience in distribution systems [88].

Continuing with the economic impacts presented in Table 2, their corresponding advantages and disadvantages are stated in Table 8.

Table 8. Advantages and disadvantages of environmental impacts.

Classification	Impact	Advantages	Disadvantages
Greenhouse gases	1	Use of renewable energy sources with minimal environmental impacts [34]. Less use of diesel generation [47]. Reduced use of thermal power plants [51].
	2		High energy expenditure during the process; therefore, large quantities of GHG are emitted [49].
	3	Reduction in GHG by the implementation of sustainable mobility [34]. Flexible charging of EVs and a reduction in system costs [50].
	4	It is based on the behavior of users through direct control and supervision programs of the energy supply or through rate control, which is an indirect program [51].
Renewable resources	1	The use of fossil fuels for energy generation is limited [34,47]. Renewable energy sources and energy storage systems are used to meet high demands, but they also promote a reduction in pollutants [91].
	2	The energy matrix is diversified using non-conventional energy sources [34,47]. Taking advantage of the country’s resources [34].	Renewable energy is weather-dependent, and it struggles to match generation to demand [91].
Investigation	1	The opportunity opens to include new forms of energy with low environmental impact and that make use of the resources present in each country [34].
Flora and fauna	1		The ecosystem is affected to include the implementation of parks for the generation of energy through renewable sources, and therefore they are considered polluting [92].
	2	Following guidelines to preserve both flora and fauna [53].
	3		Deforestation of specific areas to obtain this type of wood [49].

Table 8. Advantages and disadvantages of environmental impacts.

Classification	Impact	Advantages	Disadvantages
Greenhouse gases	1	Use of renewable energy sources with minimal environmental impacts [34]. Less use of diesel generation [47]. Reduced use of thermal power plants [51].
	2		High energy expenditure during the process; therefore, large quantities of GHG are emitted [49].
	3	Reduction in GHG by the implementation of sustainable mobility [34]. Flexible charging of EVs and a reduction in system costs [50].
	4	It is based on the behavior of users through direct control and supervision programs of the energy supply or through rate control, which is an indirect program [51].
Renewable resources	1	The use of fossil fuels for energy generation is limited [34,47]. Renewable energy sources and energy storage systems are used to meet high demands, but they also promote a reduction in pollutants [91].
	2	The energy matrix is diversified using non-conventional energy sources [34,47]. Taking advantage of the country’s resources [34].	Renewable energy is weather-dependent, and it struggles to match generation to demand [91].
Investigation	1	The opportunity opens to include new forms of energy with low environmental impact and that make use of the resources present in each country [34].
Flora and fauna	1		The ecosystem is affected to include the implementation of parks for the generation of energy through renewable sources, and therefore they are considered polluting [92].
	2	Following guidelines to preserve both flora and fauna [53].
	3		Deforestation of specific areas to obtain this type of wood [49].

In the case of the advantages and disadvantages of economic impacts, Table 9 is presented, for which it is important to consider the impacts shown in Table 3.

Table 9. Advantages and disadvantages to economic impacts.

Classification	Impact	Advantages	Disadvantages
New markets	1	It increases market competitiveness, reducing price changes [54].
	2	The opportunity arises to not depend exclusively on large generators to obtain energy [49]. Increases system flexibility on the demand side [54].
	3	New markets are being created aimed at having zero-emission mobility [34,55].
	4	Reshapes the market to derive better prices by having a clearer forecast of demand [56]. Short-term source of income for DER owners, and the system demand is managed through load shifting and peak reduction [54].
	5	Energy exchange between prosumers from wholesale to retail markets [88]. The doors of the market are opened to prosumers to manage the operations of distribution systems economically and efficiently [88].
Network operator	1	Promote market competitiveness and its proper functioning [54]. Transactional energy [88].
	2	In Colombia, certain requirements must be met for the GD connection, and the technical availability of the network on which the connection will be made must be verified [57,58]. The GD must deliver information to the OR to which it has a connection, otherwise, the OR can disconnect the GD until the breach is resolved. Likewise, it will disconnect from the network if certain requirements are not met [57,58]. Complete the documents required for the connection request, so as to carry out the corresponding studies, taking into account the protection system and the studies to be carried out [57,58].
	3	They provide flexibility to operate the system [54].	Increase in tariffs for consumers due to reduced energy consumption [51]. Investments are required to modernize the network, which can result in an economic imbalance [51].
	4	DER allows for reassessing the need for new grid infrastructure and postponing its implementation [51]. The use of storage systems and the use of renewable resources will allow savings in the investment of electrical installations in the long term and reduce carbon emissions [91].
Energy marketing	1	It is necessary to provide sustainability and accommodate the community’s ability to pay [11].	The current remuneration does not benefit the sale of energy [57,58,59].
	2		Currently, surpluses can be sold to the network operator and not to other users [57,58,59].
	3	There are conditions for competition, prices, new players and new technologies [34].
Prosumers	1	Prosumers are empowered [47].DER provides flexibility to sell energy or optimize its local use [54].
	2	In accordance with the prices or incentives that are presented [54,60,61].
	3	Adoption of devices that allow better energy control by the user [54,60,61].
Benefits	1	Incentives through regulations that enable promotion to adopt DER [65]. Tax exemptions and the free rental of facilities or land for energy storage systems encourage their use [91].
	2
	3

Table 9. Advantages and disadvantages to economic impacts.

Classification	Impact	Advantages	Disadvantages
New markets	1	It increases market competitiveness, reducing price changes [54].
	2	The opportunity arises to not depend exclusively on large generators to obtain energy [49]. Increases system flexibility on the demand side [54].
	3	New markets are being created aimed at having zero-emission mobility [34,55].
	4	Reshapes the market to derive better prices by having a clearer forecast of demand [56]. Short-term source of income for DER owners, and the system demand is managed through load shifting and peak reduction [54].
	5	Energy exchange between prosumers from wholesale to retail markets [88]. The doors of the market are opened to prosumers to manage the operations of distribution systems economically and efficiently [88].
Network operator	1	Promote market competitiveness and its proper functioning [54]. Transactional energy [88].
	2	In Colombia, certain requirements must be met for the GD connection, and the technical availability of the network on which the connection will be made must be verified [57,58]. The GD must deliver information to the OR to which it has a connection, otherwise, the OR can disconnect the GD until the breach is resolved. Likewise, it will disconnect from the network if certain requirements are not met [57,58]. Complete the documents required for the connection request, so as to carry out the corresponding studies, taking into account the protection system and the studies to be carried out [57,58].
	3	They provide flexibility to operate the system [54].	Increase in tariffs for consumers due to reduced energy consumption [51]. Investments are required to modernize the network, which can result in an economic imbalance [51].
	4	DER allows for reassessing the need for new grid infrastructure and postponing its implementation [51]. The use of storage systems and the use of renewable resources will allow savings in the investment of electrical installations in the long term and reduce carbon emissions [91].
Energy marketing	1	It is necessary to provide sustainability and accommodate the community’s ability to pay [11].	The current remuneration does not benefit the sale of energy [57,58,59].
	2		Currently, surpluses can be sold to the network operator and not to other users [57,58,59].
	3	There are conditions for competition, prices, new players and new technologies [34].
Prosumers	1	Prosumers are empowered [47].DER provides flexibility to sell energy or optimize its local use [54].
	2	In accordance with the prices or incentives that are presented [54,60,61].
	3	Adoption of devices that allow better energy control by the user [54,60,61].
Benefits	1	Incentives through regulations that enable promotion to adopt DER [65]. Tax exemptions and the free rental of facilities or land for energy storage systems encourage their use [91].
	2
	3

Table 10 shows the advantages and disadvantages evidenced in the literature based on of the impacts identified in Table 4.

Table 10. Advantages and disadvantages of social impacts.

Classification	Impact	Advantages	Disadvantages
Investigation	1	The community is led to investigate advances around the world and access new and varied information [34,47].
	2	New solutions or ideas are obtained that address specific needs [34,47].
Opportunities	1	New fields of study are opening up through which the community can be invited to research and acquire new knowledge [34,47].
	2	Have a political framework that includes training and labor market policies [49].
	3	New jobs produced throughout the renewable energy production, installation, maintenance and operation chain [49]. Employment opportunities open the doors to growth in some areas and to social revitalization with social protection [49].
Restrictions	1		Low level of knowledge due to living conditions, as access to up-to-date research material is difficult to obtain [34]. Lack of knowledge in DER, regarding how they are evolving both in the technical and commercial aspects [51].
	2		Low economic development, low energy demand and mobility restrictions [34,61].
Non-interconnected areas	1	It encourages using existing resources to generate energy and not depend on fossil fuels [34,47].	They are remote and forgotten areas that require a lot of help to get ahead and have an acceptable quality of life [54].
	2	These communities are encouraged to generate a sustainable economy, that is, to open new forms of business [34,47].
	3	By supplying energy, communities can access different services such as the internet and thus improve their quality of life [54].

Table 10. Advantages and disadvantages of social impacts.

Classification	Impact	Advantages	Disadvantages
Investigation	1	The community is led to investigate advances around the world and access new and varied information [34,47].
	2	New solutions or ideas are obtained that address specific needs [34,47].
Opportunities	1	New fields of study are opening up through which the community can be invited to research and acquire new knowledge [34,47].
	2	Have a political framework that includes training and labor market policies [49].
	3	New jobs produced throughout the renewable energy production, installation, maintenance and operation chain [49]. Employment opportunities open the doors to growth in some areas and to social revitalization with social protection [49].
Restrictions	1		Low level of knowledge due to living conditions, as access to up-to-date research material is difficult to obtain [34]. Lack of knowledge in DER, regarding how they are evolving both in the technical and commercial aspects [51].
	2		Low economic development, low energy demand and mobility restrictions [34,61].
Non-interconnected areas	1	It encourages using existing resources to generate energy and not depend on fossil fuels [34,47].	They are remote and forgotten areas that require a lot of help to get ahead and have an acceptable quality of life [54].
	2	These communities are encouraged to generate a sustainable economy, that is, to open new forms of business [34,47].
	3	By supplying energy, communities can access different services such as the internet and thus improve their quality of life [54].

Table 5 of the previous section shows the political impacts, which present certain advantages and disadvantages, as shown in Table 11.

Table 11. Advantages and disadvantages in terms of political impacts.

Classification	Impact	Advantages	Disadvantages
Incentives	Law 1715 of 2014	Income tax discounts, accelerated depreciation, exclusion of goods and services from VAT, exemption from tariff charges [65].
	Law 1964 of 2019	Discount on technical–mechanical and pollutant emissions inspections, discounts on vehicle registration or tax depending on the territorial entities, exempt from vehicle circulation restrictions, preferential parking, and guaranteeing the import of auto parts and spare parts [55].
Laws	Law 143 of 1994	It establishes the regime for the generation, transmission, interconnection, distribution and commercialization of electricity [31].
Regulations	RETIE draft 2022	It seeks to establish the installation requirements, connection to the system, necessary protections and the viability of the DER connection in Colombian territory [67].
Resolutions	Resolution 281 of 2015	The generation limit will be 1 MW, which corresponds to the installed capacity of the self-generator [69].
	Resolution 024 of 2015	It applies to large-scale self-generators connected to the SIN, both for their connection and measurement, and must also have support from the network and provide the conditions for the delivery of surpluses [70].
	Resolution 40072 of 2018	The mechanisms for implementing AMI in the public energy service and the entities to which it is applicable are established. Likewise, the objectives for the implementation of these and their basic functionalities are established [71].
	Resolution 019 of 2018	Small-scale [72] self-generator users were added to CREG 108 of 1997.
	Resolution 030 of 2018	It regulates small-scale self-generation activities and DG connected to the SIN. Therefore, it is applicable to the Ors and the marketing companies that serve them, and national transmitters [57].
	Resolution 40807 of 2018	It involves the adoption of a comprehensive climate change plan in the mining and energy sector and integrates the vision towards carbon neutrality and climate resilience by 2050 [73,74].
	Resolution 060 of 2019	Allows the connection and operation of photovoltaic solar and wind plants in the SIN [68].
	Resolution 137 of 2020	The general rate for the remuneration of the energy service through photovoltaic solar energy is defined [75].
	Resolution 170 of 2020	The connection and operation of photovoltaic solar and wind plants in the local distribution system (SDL) is permitted, which have a power equal to or greater than 5 MW [76].
	Resolution 173 of 2021	It allows the connection and operation of photovoltaic solar and wind plants in the SDL greater than 1 MW and less than 5 MW [77].
	Resolution 174 of 2021	It regulates small-scale self-generation and DG activities in the SIN, in operational and commercial matters [78].
	Resolution 148 of 2021	It allows the connection and operation of photovoltaic solar and wind plants in the SDL with a capacity equal to or greater than 5 MW [79].
Decrees	Decree 348 of 2017	Public policy guidelines are established for the efficient management of energy and delivery of small-scale self-generation surpluses [80].
Studies	Smart grid vision 2030—UPME	This study presents the background and conceptual framework for the analysis, evaluation and recommendations for the implementation of smart grids in Colombia, and proposes the road map and regulatory framework for the implementation of smart grids in the country [81].

Table 11. Advantages and disadvantages in terms of political impacts.

Classification	Impact	Advantages	Disadvantages
Incentives	Law 1715 of 2014	Income tax discounts, accelerated depreciation, exclusion of goods and services from VAT, exemption from tariff charges [65].
	Law 1964 of 2019	Discount on technical–mechanical and pollutant emissions inspections, discounts on vehicle registration or tax depending on the territorial entities, exempt from vehicle circulation restrictions, preferential parking, and guaranteeing the import of auto parts and spare parts [55].
Laws	Law 143 of 1994	It establishes the regime for the generation, transmission, interconnection, distribution and commercialization of electricity [31].
Regulations	RETIE draft 2022	It seeks to establish the installation requirements, connection to the system, necessary protections and the viability of the DER connection in Colombian territory [67].
Resolutions	Resolution 281 of 2015	The generation limit will be 1 MW, which corresponds to the installed capacity of the self-generator [69].
	Resolution 024 of 2015	It applies to large-scale self-generators connected to the SIN, both for their connection and measurement, and must also have support from the network and provide the conditions for the delivery of surpluses [70].
	Resolution 40072 of 2018	The mechanisms for implementing AMI in the public energy service and the entities to which it is applicable are established. Likewise, the objectives for the implementation of these and their basic functionalities are established [71].
	Resolution 019 of 2018	Small-scale [72] self-generator users were added to CREG 108 of 1997.
	Resolution 030 of 2018	It regulates small-scale self-generation activities and DG connected to the SIN. Therefore, it is applicable to the Ors and the marketing companies that serve them, and national transmitters [57].
	Resolution 40807 of 2018	It involves the adoption of a comprehensive climate change plan in the mining and energy sector and integrates the vision towards carbon neutrality and climate resilience by 2050 [73,74].
	Resolution 060 of 2019	Allows the connection and operation of photovoltaic solar and wind plants in the SIN [68].
	Resolution 137 of 2020	The general rate for the remuneration of the energy service through photovoltaic solar energy is defined [75].
	Resolution 170 of 2020	The connection and operation of photovoltaic solar and wind plants in the local distribution system (SDL) is permitted, which have a power equal to or greater than 5 MW [76].
	Resolution 173 of 2021	It allows the connection and operation of photovoltaic solar and wind plants in the SDL greater than 1 MW and less than 5 MW [77].
	Resolution 174 of 2021	It regulates small-scale self-generation and DG activities in the SIN, in operational and commercial matters [78].
	Resolution 148 of 2021	It allows the connection and operation of photovoltaic solar and wind plants in the SDL with a capacity equal to or greater than 5 MW [79].
Decrees	Decree 348 of 2017	Public policy guidelines are established for the efficient management of energy and delivery of small-scale self-generation surpluses [80].
Studies	Smart grid vision 2030—UPME	This study presents the background and conceptual framework for the analysis, evaluation and recommendations for the implementation of smart grids in Colombia, and proposes the road map and regulatory framework for the implementation of smart grids in the country [81].

Finally, Table 12 presents the advantages and disadvantages evidenced in the literature, based on the impacts identified in Table 6.

Table 12. Advantages and disadvantages of sectoral impacts.

Classification	Impact	Advantages	Disadvantages
Decentralization	1	In Colombia, ORs become DSOs, through which the exchange of energy services can be carried out, thus encouraging the emergence of new agents, activities and products within the electricity market [59]. DSO and TSO will need to take on new roles [51,61]. DSO and TSO could work together to define techniques for participating in specialized markets and define standardized products [60]. With the appropriate regulations, DSO can provide services from DER [51]. DSO and TSO must coordinate, supervise and dispatch resources, as well as share and study information in a timely manner [93].	They are very private entities that are not open to sharing information [94]. The necessary knowledge about the technical and commercial advances of DER is not yet available [51]. Distributors view the entry of new agents into the sector negatively [51].
	2		The technical, operational and planning areas of the operators are affected [93].
	3	With the arrival of DER, new criteria for grid reconstruction are needed [51]. Introduce mechanisms that encourage the inclusion of DER [51].	Regulatory limitations are a political barrier to DER integration [51].
	4	Establish correct and satisfactory operation of the entire system [64]. DSOs can be DER operators [64].
Integration	1	The union of different parts allows progress towards DER integration, and also manages its proper entry, maintaining a quality service [85]. There are multiple beneficiaries, since it opens the opportunity for new businesses, branches of study and policies that benefit the entry of DER based on the system [85]. For communities to be resilient and sustainable, cooperation between industry and organizations is necessary [95].
	2	Devices with optimal features can be obtained to ensure high-quality, safe and reliable equipment.

Table 12. Advantages and disadvantages of sectoral impacts.

Classification	Impact	Advantages	Disadvantages
Decentralization	1	In Colombia, ORs become DSOs, through which the exchange of energy services can be carried out, thus encouraging the emergence of new agents, activities and products within the electricity market [59]. DSO and TSO will need to take on new roles [51,61]. DSO and TSO could work together to define techniques for participating in specialized markets and define standardized products [60]. With the appropriate regulations, DSO can provide services from DER [51]. DSO and TSO must coordinate, supervise and dispatch resources, as well as share and study information in a timely manner [93].	They are very private entities that are not open to sharing information [94]. The necessary knowledge about the technical and commercial advances of DER is not yet available [51]. Distributors view the entry of new agents into the sector negatively [51].
	2		The technical, operational and planning areas of the operators are affected [93].
	3	With the arrival of DER, new criteria for grid reconstruction are needed [51]. Introduce mechanisms that encourage the inclusion of DER [51].	Regulatory limitations are a political barrier to DER integration [51].
	4	Establish correct and satisfactory operation of the entire system [64]. DSOs can be DER operators [64].
Integration	1	The union of different parts allows progress towards DER integration, and also manages its proper entry, maintaining a quality service [85]. There are multiple beneficiaries, since it opens the opportunity for new businesses, branches of study and policies that benefit the entry of DER based on the system [85]. For communities to be resilient and sustainable, cooperation between industry and organizations is necessary [95].
	2	Devices with optimal features can be obtained to ensure high-quality, safe and reliable equipment.

5. Qualitative Assessment of the Impacts of DER Integration

The change of the electrical systems is imminent, and to carry this out, new agents are introduced into the system. By introducing these agents, the structures of the networks are changed, since the system is decentralized and digitalized, and in this way, they contribute to the decarbonization of energy generation. In this sense, we see the integration of DER, which is introduced to promote the empowerment of users and optimize the system [10].

The impacts evidenced in the scientific literature have both advantages and disadvantages, as described in Section 4. Now, based on what was found in the previous section, a qualitative evaluation of all the impacts is carried out, as evidenced in Table 13.

According to the literature reviewed and analyzed, a qualitative evaluation is here made of the impacts found, whereby it is evident that there are impacts due to the integration of DER in the electrical networks in positive, negative and both ways; this classification is made according to the advantages and disadvantages that each impact offers and that were found in each study reviewed. This criterion is of great usefulness since it allows us to analyze what type of solution can be found for the case of negative impacts, and on the contrary, which cases allow us to strengthen the positive impacts that lead to an improvement in the planning and operation of the electrical networks.

Considering the above, in order to carry out the qualitative evaluation, three criteria were defined to rate the impacts, as follows: positive (+), negative (−) and positive (+)/negative (−). The respective rating of each impact was based on the advantages and disadvantages of each one, that is, if an impact only presents advantages, it is rated as positive (+), while on the other hand, if the impact only presents disadvantages, it is rated as negative (−), and if the impact has both advantages and disadvantages, it is rated as positive (+)/negative (−).

Table 13. Qualitative assessment of impacts.

	Classification	Impact	Positive (+)	Positive (+)/Negative (−)	Negative (−)	Reference
TECHNICAL	Power quality	1		+/−		[10,12,86]
		2		+/−	; −	[10,14,23,87]
		3		+/−	; −	[12,23,88]
		4		+/−	; −	[10,21,50]
		5	+			[16,20]
		6	+,	+/−		[17,18,19]
	Stability	1			−	[10,12]
		2			−	[89]
		3			−	[86]
		4	+		; −	[10,17,20,23,44]
		5	+		; −	[16,19,23,25]
		6		+/−	; −	[24,30]
		7	+			[21,22,26,28,29]
	Protections	1		+/−	; −	[12,19,88]
		2			−	[86,90]
		3			−	[86]
		4		+/−		[86,90]
		5			−	[86,90]
		6		+/−		[12,23,33]
	Cybersecurity	1		+/−		[11]
		2		+/−		[11]
		3	+			[11,22]
		4			−	[11]
		5			−	[23,24,30]
	Reliability	1	+;	+/−	; −	[18,26,29,30,34,36,37,38,40,41,43,86,88]
		2	+			[19,20,22,28,34,35,36,42,45,88,91]
		3	+			[39]
		4	+	; +/−		[17,24,33]
		5	+			[44]
ENVIRONMENTAL	Greenhouse gases	1	+			[28,34,47,51]
		2			−	[49]
		3	+			[21,22,25,29,30,34,37,41,42,43,50]
		4	+			[51]
	Renewable resources	1	+			[34,35,41,47,90]
		2	+			[33,34,37,47,91]
		3	+;	+/−		[19,20,21,22,23,25,28,29,30,33,36,39,40,44,45]
		4	+			[42]
	Investigation	1	+			[34,35,36]
	Flora and fauna	1			−	[92]
		2	+			[53]
		3			−	[49]
ECONOMIC	New markets	1	+			[54]
		2	+			[38,49,54]
		3	+			[34,55]
		4	+			[54]
		5	+			[37,88]
	Network operator	1	+			[54,91]
		2	+			[57,58]
		3	+;	+/−	; −	[19,21,22,23,30,33,39,45,51,54]
		4	+			[29,33,43,54,91]
		5	+			[16,20,22,24,25,28,36,37,40,41,42,44]
		6	+
	Energy marketing	1		+/−		[11,57,58,59]
		2			−	[58,59]
		3	+			[34]
	Prosumers	1	+			[47,54]
		2	+			[21,47,60,61]
		3	+			[47,60,61]
		4	+			[44]
	Benefits	1	+			[65,91]
		2	+			[65,91]
		3	+			[65,91]
		4	+			[36,45]
		5	+			[16,17,18,20,21,22,26,28,30,33,37,40,41,43]
		6	+			[26,29]
SOCIAL	Investigation	1	+			[34,35,47]
		2	+			[34,47]
		3	+			[36,41,42]
	Opportunities	1	+			[21,34,36,47]
		2	+			[49]
		3	+			[49]
	Restrictions	1			−	[34,51]
		2			−	[34,61]
		3		+/−		[36]
	Non−interconnected areas	1		+/−		[34,47]
		2		+/−		[34,47]
		3		+/−		[63]
POLITICIAL	Incentives		+			[38,55,65]
	Laws		+			[31]
	Regulations		+			[19,66]
	Resolutions		+			[57,68,69,70,71,72,73,74,75,76,77,78,79,85]
	Decrees		+			[90]
	Studies		+			[91]
SECTORIAL	Decentralization	1	+;	+/−		[23,42,51,59,60,61,93,94]
		2	+	;	−	[21,22,28,29,30,40,41,43,93]
		3	+;	+/−		[19,26,51]
		4	+			[33,37,64]
	Integration	1	+			[29,85,95]
		2	+			[21,22,23,35]
		3	+			[18,19,23,26,28,30,33,35,36,37,38,40,41,42,43]
		4	+			[43]

Table 13. Qualitative assessment of impacts.

	Classification	Impact	Positive (+)	Positive (+)/Negative (−)	Negative (−)	Reference
TECHNICAL	Power quality	1		+/−		[10,12,86]
		2		+/−	; −	[10,14,23,87]
		3		+/−	; −	[12,23,88]
		4		+/−	; −	[10,21,50]
		5	+			[16,20]
		6	+,	+/−		[17,18,19]
	Stability	1			−	[10,12]
		2			−	[89]
		3			−	[86]
		4	+		; −	[10,17,20,23,44]
		5	+		; −	[16,19,23,25]
		6		+/−	; −	[24,30]
		7	+			[21,22,26,28,29]
	Protections	1		+/−	; −	[12,19,88]
		2			−	[86,90]
		3			−	[86]
		4		+/−		[86,90]
		5			−	[86,90]
		6		+/−		[12,23,33]
	Cybersecurity	1		+/−		[11]
		2		+/−		[11]
		3	+			[11,22]
		4			−	[11]
		5			−	[23,24,30]
	Reliability	1	+;	+/−	; −	[18,26,29,30,34,36,37,38,40,41,43,86,88]
		2	+			[19,20,22,28,34,35,36,42,45,88,91]
		3	+			[39]
		4	+	; +/−		[17,24,33]
		5	+			[44]
ENVIRONMENTAL	Greenhouse gases	1	+			[28,34,47,51]
		2			−	[49]
		3	+			[21,22,25,29,30,34,37,41,42,43,50]
		4	+			[51]
	Renewable resources	1	+			[34,35,41,47,90]
		2	+			[33,34,37,47,91]
		3	+;	+/−		[19,20,21,22,23,25,28,29,30,33,36,39,40,44,45]
		4	+			[42]
	Investigation	1	+			[34,35,36]
	Flora and fauna	1			−	[92]
		2	+			[53]
		3			−	[49]
ECONOMIC	New markets	1	+			[54]
		2	+			[38,49,54]
		3	+			[34,55]
		4	+			[54]
		5	+			[37,88]
	Network operator	1	+			[54,91]
		2	+			[57,58]
		3	+;	+/−	; −	[19,21,22,23,30,33,39,45,51,54]
		4	+			[29,33,43,54,91]
		5	+			[16,20,22,24,25,28,36,37,40,41,42,44]
		6	+
	Energy marketing	1		+/−		[11,57,58,59]
		2			−	[58,59]
		3	+			[34]
	Prosumers	1	+			[47,54]
		2	+			[21,47,60,61]
		3	+			[47,60,61]
		4	+			[44]
	Benefits	1	+			[65,91]
		2	+			[65,91]
		3	+			[65,91]
		4	+			[36,45]
		5	+			[16,17,18,20,21,22,26,28,30,33,37,40,41,43]
		6	+			[26,29]
SOCIAL	Investigation	1	+			[34,35,47]
		2	+			[34,47]
		3	+			[36,41,42]
	Opportunities	1	+			[21,34,36,47]
		2	+			[49]
		3	+			[49]
	Restrictions	1			−	[34,51]
		2			−	[34,61]
		3		+/−		[36]
	Non−interconnected areas	1		+/−		[34,47]
		2		+/−		[34,47]
		3		+/−		[63]
POLITICIAL	Incentives		+			[38,55,65]
	Laws		+			[31]
	Regulations		+			[19,66]
	Resolutions		+			[57,68,69,70,71,72,73,74,75,76,77,78,79,85]
	Decrees		+			[90]
	Studies		+			[91]
SECTORIAL	Decentralization	1	+;	+/−		[23,42,51,59,60,61,93,94]
		2	+	;	−	[21,22,28,29,30,40,41,43,93]
		3	+;	+/−		[19,26,51]
		4	+			[33,37,64]
	Integration	1	+			[29,85,95]
		2	+			[21,22,23,35]
		3	+			[18,19,23,26,28,30,33,35,36,37,38,40,41,42,43]
		4	+			[43]

A total of 70 impacts were found at a general level based on the scientific literature. In this context, Figure 3 shows the percentage of each impact that is incurred when including DER in the electric power system.

Considering the above, it can be said that the highest percentage of impacts is that of technical impacts, at 29%. Therefore, it is possible to show that the functioning of the networks is affected when integrating DER into an electrical system. However, when considering the system, it is also important to consider the other impacts, of which 27% are economic, followed by environmental and social impacts, with 14% each, and ending with political and sectoral impacts, which contribute 8% of the total.

Now, based on Figure 4, it is evident that 53% of the impacts found in the scientific literature are positive, that is, of the total of 70 impacts, 37 are positive, while 24% are negative and 23% are positive and negative. The above is of great importance, since it shows that the integration of DER brings with it many positive aspects to electrical systems when considered globally. On the other hand, since DER is a research topic, it is possible to seek to solve or mitigate those negative impacts.

6. Discussion

In order to determine the challenges and alternatives to the integration of DERs into the energy system and to face them, the first phase of this “Review” document, “Analysis of Impacts in Electric Power Grids Due to the Integration of Distributed Energy Resources”, was carried out. With the results of this work, it was possible to determine, according to the scientific, political and regulatory publications, the following:

• DERs are alternative solutions to address the energy and environmental crisis, but they produce different impacts of various kinds when they are integrated into the electrical grid;
• It is necessary to identify the impacts on the energy system in view of the integration of DERs;
• It is essential and necessary to take the first step of research into the identification of the impacts of the integration of DER in the electrical networks, and that they are qualitatively classified as positive or negative impacts, or operating in both directions. This classification allows us to derive criteria to analyze possible solutions in case the impact is negative, or on the contrary which cases allow us to potentiate the positive impacts that lead to an improvement in the planning and operation of the electrical networks, but this should be done in another study;
• Some research questions arise from the understanding of the research topic addressed in this article, such as what are the types of impacts related to the integration of DERs into the energy system, and how can these impacts be classified and evaluated, as well as what are the techniques currently used?
• The correlations between the monitored variables that indicate the characteristics of the electricity system and which DERs have an impact on each technical variable of the system are not defined, so tools for quantifying the technical impacts and support to the regulatory limits that allow obtaining a reliable, safe and resilient electricity system in the face of the integration of DERs must be proposed. However, this will be part of other research;
• With the results obtained in this article, the emerging and driving themes are identified as potential research works, subsequently a detailed study will be carried out on the quantification of the technical impacts of the integration of DERs to the interconnected electrical system or in isolated areas, as well as theories, methods or solution strategies related to them. In this same study, a prospective of the technological progress of the research topics evidenced through the timeline will be made, but this is part of a second research that is being developed at this time and is not part of this article.

7. Conclusions

According to the qualitative evaluation carried out, it can be concluded that this is a very important tool used to visualize the effects that come with the integration of DER into an electric power system, whether positive, negative or positive/negative, and to take these effects into account when proposing solutions or alternatives that allow the integration of DER in an optimal way, highlighting that of all the impacts, more than half are of a positive nature according to the information presented.

With this review into the analysis of impacts in electric power grids due to the integration of distributed energy resources, it was possible to establish that although there are different proposals for solutions, there are still gaps and a lack of knowledge about the most appropriate techniques, methods or strategies for impact mitigation. In this context, there are critical and monitored variables that the DSO should analyze to enable timely and optimal decision-making, as well as to establish the desired characteristics of the electrical system, on which it should exercise surveillance and control to ensure that they are guaranteed.

Considering the research carried out, it can be concluded that DERs, being emerging and changing technologies, require continuous research as they are integrated into an electrical system to establish the characteristics that are modified in it at a general level, and from which it is possible to seek alternative solutions and ways to enhance the use of these resources.

According to the qualitative evaluation carried out, it can be concluded that this is a very important tool that can be used to visualize the effects that come with the integration of DER into an electric power system, whether these be positive, negative or positive/negative, and to take these effects into account to propose solutions or alternatives that allow the integration of DER in an optimal way, highlighting that of all the impacts, more than half are of a positive nature, according to the information presented.

The contribution of each impact within the electrical system when integrating DER has been performed. From this, it can be concluded that out of 100%, the impacts that make the highest percentage of contribution are the technical impacts. Considering the above, it is important to highlight that 50% of the technical impacts present negative effects that must be mitigated within the operation of the network. These challenges are addressed by companies in the electrical sector, some of which are the subject of much research worldwide.