New Microgrid Architectures for Telecommunication Base Stations in Non-Interconnected Zones: A Colombian Case Study

Abstract

This paper proposes a novel microgrid (MG) architecture designed for telecommunication base stations in non-interconnected regions, with the main objective of mitigating mobile service interruptions caused by power outages. This research consists of three key modules: the first module on resources and components, the second module on characterization, and the third module on design and methodology. The first module presents a comprehensive identification and description of the resources and components of the microgrid within the base station; the second module characterizes the topology and specific configurations of the microgrid; and the last module covers a new methodology for the installation of microgrids in geographic areas lacking electrification, which becomes the contribution of this research work. The novelty of this research presents new control architectures, energy management, and system optimization, including technical–economic analysis. The research outcome highlights the economic and social benefits for both local communities and mobile phone service providers. This research aims to establish a guideline on how these factors affect the focus region of this research. With this technological proposal, a continuous and uninterrupted mobile service is achieved, thus improving the quality of service and minimizing the failures induced by electricity in non-interconnected areas. The tests and validation of the system were carried out with Homer Pro software, integrating socioeconomic and environmental factors. The results obtained present a key solution for this type of application, minimizing costs and increasing reliability for users.

1. Introduction

Today, access to electricity is essential for the comprehensive development of communities in any country. Communities that do not have access to electricity suffer and experience negative impacts on their development, such as a direct impact on the health of residents, limited opportunities for children and adolescents to study, and reduced productivity and employment. In general, the quality of life of all members of a community is greatly affected by a lack of electricity. Microgrids aim to guarantee a better quality of energy supply from the point of view of resiliency, which is related to a service with the least number of interruptions and that does not come from a single generation source [1]. In this sense, a microgrid is an energy network that can potentially disconnect from the National Interconnected System (NIS) to operate autonomously and thus support it via ancillary services. This aims to reduce disturbances and interruptions, strengthening the response and recovery capacity of the network when power outages and faults occur [2].

According to the definition set forth in Colombia’s Indicative Expansion and Coverage Plan (IECP), a microgrid is defined as “an electric system that integrates demand (loads) and distributed energy resources with the capability to operate over a time period with several layers of automation and coordination, (either isolated or interconnected to a main utility grid), under technical, economic and socio-cultural criteria” [3].

Following the IECP definition, the challenge is to design a microgrid that operates in autonomous (island) mode, achieving a constant energy supply to any telecommunications base station (BTS). A BTS is a station for the transmission and reception of radio signals located in a fixed location, comprising a set of power electronic conversion systems, receiving/transmission antennas, microwave antennas, and other equipment and/or components that the telecommunications operator has for its operation [4].

A BTS is commonly used to handle mobile telephony traffic in order to guarantee a good mobile telephony service. This article addresses the microgrid design targeted to non-interconnected zones (NIZs), where telecommunications companies, in their effort to provide extensive coverage across the national territory, are present through base stations that are energetically supplied by electric plants. These plants, when they fail due to a lack of maintenance, damage caused by overloads, theft, or simply running out of fuel, cause the BTS to lose electrical power, directly affecting the users under that coverage.

This is a subject that is in full development, and its purpose is to contribute to the research field and propose a solution to ensure an electric power supply in areas where this service is lacking. It should be kept in mind that microgrids that are not connected to the National Interconnected System (NIS) have been used for several years to provide energy services in areas where the total demand does not economically justify the investment costs for large-scale deployment into the national power grid. This is performed with the aim of improving the quality of life for the inhabitants of these regions by ensuring continuous connectivity and uninterrupted mobile service, which, over the years, has become an essential service in daily life.

It is important to note that both the inhabitants of these areas and the telecommunications companies would benefit from the implementation of this research, as it would significantly improve the perception of the service, guaranteeing better coverage. In Colombia, various proposals in the field of microgrids have focused on evaluating the feasibility of implementing both grid-connected and isolated technologies [5]; likewise, work has been performed on microgrid regulation and operation [6] and even the use of digital twins to validate new AI-based technologies [7]. This article is structured in four sections. Initially, Section 1 describes the information related to microgrids in the NIZs of our country; then, Section 2 presents the new design of the microgrid for the base stations in our specific case. Section 3 presents the results, and Section 4 closes with the conclusions of this research.

The contributions of this work are presented as follows:

• This paper presents a new design for an isolated microgrid for telecommunication base stations (BTSs) in non-interconnected areas.
• This research presents new control architectures, energy management, and system optimization, including technical–economic analysis.
• The research outcome highlights the economic and social benefits for both local communities and mobile phone service providers.
• This research aims to establish a guideline on how these factors affect the focus region of this research.

2. Methodology

A research study was initially conducted on the use of MGs as a technological solution that implements distributed energy resources (DERs), such as solar, wind, and hydraulic in non-interconnected areas.

2.1. Microgrids in Non-Interconnected Areas in the Colombian Context

In Colombia, about 52% of the territory is classified as non-interconnected zones (NIZs) [3], which means that a large part of the base stations of the telecommunications service providers are located in these areas. In these areas, the base stations are only supplied with energy through an electrical plant, which is directly responsible for the electrical operation. But when the plants fail, either due to a lack of maintenance, damage caused by overloads, theft, or simply running out of fuel, they leave the base station without power, generating failures in its electrical network and directly affecting the users located under the coverage of such a base station.

Since 2016, with the issuance of Resolution 5050 of November 21, which establishes that failures that leave 100% of users without coverage in a municipality and exceed 60 min both in the mobile and fixed networks must be reported to the Ministry of Information Technologies and Communications (MINTIC) [8]. It should be clarified that the MINTIC is the entity in charge of regulating all communications events and that one of its functions, as stated in the aforementioned resolution, is to ensure that the end user receives a quality service. If this is not the case, it must intervene by evaluating the causes and applied solutions to determine why the operator is not providing a quality service and make decisions on whether or not the operator should be fined, as the case may be.

Considering that most of the NIZs are located in areas that are difficult to access, either due to geographical location or public order, the solutions to most of these failures require considerable travel times of one to two hours, for base stations that are slightly accessible, and up to one or two days, for locations that are difficult to access. This implies a considerable delay in the restoration of services to users and results in economic penalties for the operator. From the above, it is concluded that by reducing these failures through this type of research, it will be possible to provide better service and reduce the cost of fines imposed by the regulatory authority on telecommunications companies.

Based on the above, the idea arises to design a microgrid capable of guaranteeing an average generation of (90–92) kWh/month, which will aim to supply energy to the BTS without interruptions. This is the basic average consumption established by the Indicative Plan for Expanding Coverage (IECP), entitled for workshops, stores, schools, health centers, and other businesses or buildings that contribute to the development of the area [3]. The idea is to provide electrical support to the BTS in these areas (NIZs) with a new distributed generation system through distributed energy resources (DERs), with the aim of minimizing failures caused by relying on a single means of electrical supply (generator set) in these base stations.

According to Decree 1523 of 2015, the main objectives of the IECP (Instrument for Stratification of Electric Power Coverage) are to assess the demand for electricity services in non-interconnected areas and to estimate the investments required to achieve universal access. These objectives and the proposed alternatives are illustrated in the diagram shown in Figure 1 [3]. This figure outlines the IECP’s proposal through three technical solutions based on geographical and logistical conditions.

Figure 1 indicates that for each of the locations without electricity, the interconnection alternative is initially evaluated depending on the proximity to the electrical infrastructure. Then, for locations that are outside the area of influence of the medium-voltage and low-voltage networks, and if the group of homes without service in each location exceeds 25 homes, the cost of a microgrid is estimated. In cases where the number of homes without service is less than 25 users, the isolated individual solution is considered the best alternative. These off-grid alternatives are added to the interconnection solution described above, thus completing the best possible alternative for each location and quantifying the cost of universalization. In this regard, three types of options are presented:

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Areas located near the National Interconnected System (NIS): a network extension of up to 1.5 km is proposed to connect the isolated zone.

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Remote or hard-to-reach areas: Off-grid solutions are recommended, typically consisting of individual solar panel systems for dispersed households.

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Densely populated zones: Microgrid (MG) systems are suggested to supply energy collectively and autonomously.

In the legal context, Colombian microgrids are governed by Resolution 030 of 2018 [9], Resolution 038 of 2018 [10] issued by the Ministry of Mines and Energy and the Energy and Gas Regulatory Commission (CREG), Resolution 203 of 2020 [11] from the Mining-Energy Planning Unit (UPME), Law 1715 of 2014 [12], and Resolution 186 of 2012 from the Ministry of Environment and Sustainable Development [13]. These provide clear guidelines on the steps to follow in constructing projects like this one, outlining both the legal obligations and the benefits of engaging in clean energy projects. Additionally, these guidelines, obligations, and benefits are driven by the mining and energy transition, incorporating criteria of environmental, social, energy, and tariff justice [14].

Disconnected or isolated solutions, also known as off-grid, refer to electric microgrids (MGs) and individual solar panel systems for communities in non-interconnected zones (NIZ). The use of MGs is justified in clusters of at least 25 dwellings within a radius of 1.5 km, with a potential demand for unit electricity exceeding the minimum residential consumption of individual solar panel systems. In addition, these groups must have users such as shops, small workshops, schools, health posts, police stations, water pumping systems for the population, and other institutions and/or businesses. As MGs are designed to supply electricity through a low-voltage and alternating-current network, new technologies can interconnect medium-voltage networks in the future [1,4].

The results of the IECP indicate that a significant financial investment is essential to achieve universal access to electricity across the national territory. Funding should be allocated to the expansion of the Local Distribution System (SDL), the development of hybrid isolated microgrids, and the implementation of individual off-grid solutions. In this context, this research contributes to the IECP by supporting the densification and expansion of electric grids in the country [3]. Figure 2 presents the hybrid microgrid and individual photovoltaic (PV) solutions currently available in the country. The results of this IECP indicate that Colombia needs to provide electricity coverage to around 530,000 registered homes by 2023, of which 9% correspond to the expansion of the SDL, 48% to isolated solutions with hybrid microgrids, and 43% to individual isolated solutions [2,6], as shown in Figure 2.

ZINs are divided or classified into four types, which are presented in

Table 1. Typologies in the NIZs.

Typology of Localities	Type 1	Type 2	Type 3	Type 4
Number of users	1 to 50	51 to 150	151 to 300	more than 300
Monthly demand (kWh/user)	33.6	45	76	greater than 76
Daily consumption (kWh/users)	1.12	1.5	2.53	greater than 2.53
Daily consumption range (kWh)	1.12 to 56	76.5 to 225	11,476 to 22,800	over 22,800
Hours of service (h)	4	5	8	10 to 14

. The types of ZINs are defined by the number of users in the area, as established in Article 25 of Resolution 40,239 of 2022, taking into account the data collected by the Single Information System (SIS). It can be seen that the largest number of users is found in type 1 locations, with 42.1% of the total, followed by type 3, with 31.7%, type 2, with 16.3%, and, finally, type 4, with 9.9%, indicating that the number of users is mainly concentrated in the largest localities [1,2,4]. Table 1 shows the classification by type of user, monthly demand, daily consumption, daily consumption range, and hours of service provided for each type. This classification is detailed below in Table 1.

2.2. New Microgrid Design for Base Stations in Telecommunications: The Colombian Case Study

This research proposes the design of a microgrid with a capacity of 90–92 kWh/month for non-interconnected zones (NIZs), aiming to mitigate electrical failures and thereby enhance mobile telephony services. Notably, the design can be applied to any NIZ base station across the national territory. In this particular study, the coastal area of the department of Chocó was chosen as the case study due to its environmental, social, and economic conditions, with the goal of fostering improved quality of life for the inhabitants of the southwestern region of the country.

A review of statistical data from a telecommunications company revealed that the municipalities with the highest frequency of such failures are Bahía Solano, El Litoral del San Juan, Sipí, Juradó, Nuquí, and Bajo Baudo.

Approximately 52% of Colombia’s territory is classified as NIZs, with an estimated 1795 areas falling under this category. These zones include municipalities, townships, hamlets, and rural population centers distributed throughout the national territory. The southwestern region of Colombia, particularly the departments of Nariño, Cauca, Valle del Cauca, and Chocó, is the most affected, accounting for over 1000 of these NIZs.

The data presented in Figure 3 were provided by the Indicative Plan for the Expansion of Electric Power Coverage, which confirms that the southwestern region of Colombia is the most affected by this issue. Based on this information, and with the aim of improving the quality of life of the population in the region, the project initially selected the departments of Nariño, Cauca, Valle del Cauca, and Chocó as potential candidates. Subsequently, several factors were analyzed, including geographic location, economic and social development, and the number of areas (municipalities, townships, hamlets, and rural population centers) not connected to the NIS, among other relevant aspects, both for the project’s impact and for the microgrid design.

Following a detailed analysis of each department, Chocó was identified as the most suitable for the implementation of the proposed project. This decision was based on its coastal location, which directly influences the potential use of renewable energy sources, an essential component in the design of the microgrid, as well as the high number of NIZs within its territory. Additionally, the project sought to contribute to regional development and improve the living conditions of its inhabitants. These considerations led to the selection of Chocó, specifically its coastal area, which borders both the Pacific and Atlantic Oceans.

Table 2. Municipalities, telecommunication base stations, and electricity supply aspects.

Department DANE	Code DANE Municipality	Municipality DANE	Base Stations	Communication Technologies	Electrical Supply
CHOCO	27,075	BAHÍA SOLANO	CHO.Bahia Solano	GSM/UMTS/LTE	Power Plants
			CHO.El Valle
	27,250	EL LITORAL DEL SAN JUAN	CHO.Docordo
	27,745	SIPÍ	CHO.Sipi
	27,372	JURADÓ	CHO.Bahia Cupica
			CHO.Jurado
	27,495	NUQUI	CHO.Nuqui
	27,077	BAJO BAUDÓ	CHO.Pizarro

provides contextual information relevant to the selected geographic area, namely, the department of Chocó. Chocó is one of the 32 departments that make up the national territory of Colombia. It is located in the western part of the country and belongs to the Pacific region. Notably, it is the only department in Colombia with coastlines on both the Pacific and Atlantic Oceans. Chocó covers an area of 46,590 km², representing 4.07% of the national territory, and has a population of 505,016, which accounts for 1.04% of the country’s total population. Its capital is the municipality of Quibdó, and it is politically and administratively composed of 30 municipalities, 234 townships, 71 hamlets, and 78 rural population centers. Among these, 509 are classified as NIZs.

Figure 4 shows the geographical area where this research was carried out [15].

Therefore, the proposal is to design an isolated microgrid—typically consisting of photovoltaic, wind, diesel, and battery systems—to serve the base station, whose average consumption ranges between 90 and 92 kWh/month, in accordance with the IECP. Figure 5 presents the block diagram of the proposed design based mainly on six methodological steps that were found in [16,17], summarized as follows: collect information from the microgrid, estimate load profiles, size the elements of the microgrid, define the topology of the microgrid, perform feasibility analysis, and make adjustments to the microgrid design. The following sections describe each of the microgrid components, including a wind turbine, a battery bank, and a diesel generator.

Wind generator: In a wind power system, an AC/DC converter (rectifier) is used to transform the alternating current (AC) generated by the wind turbine—which typically has a variable frequency due to changing wind speeds—into direct current (DC). This rectifier is particularly useful in configurations with induction generators or permanent magnet synchronous generators (PMSGs), which operate at low frequencies or require adjustments for grid synchronization. Subsequently, an inverter (DC/AC converter) converts the DC power back into grid-compatible AC power with the correct voltage and frequency. This inverter plays a key role in controlling active (P) and reactive (Q) power, ensuring grid stability, energy efficiency, and fault protection.

Battery bank (Lithium-ion): A battery bank is a key component in renewable energy systems and backup applications, as it stores energy for later use, regulated by a bidirectional DC/DC converter that controls the energy flow between the batteries (with variable voltage) and the system’s direct current (DC) bus. This converter operates in Buck mode to charge the batteries when there is excess energy (reducing the DC bus voltage) and in Boost mode to discharge them when the system requires power (increasing the battery voltage to the DC bus level) while also including protections such as maximum current control and overcharge/overdischarge prevention. Its bidirectional design provides higher efficiency, flexibility in integrating intermittent renewable energy sources, and autonomy in off-grid or backup systems, making it suitable for standalone photovoltaic systems, microgrids, electric vehicles (V2G), and power grid stabilization.

Photovoltaic generator: A photovoltaic generator consists of solar panels that convert sunlight into direct current (DC) electricity, with its output voltage and current varying based on solar irradiation and temperature conditions, requiring a DC/DC boost converter to increase the input voltage to a higher, stable level compatible with the system’s DC bus or inverter input. To maximize energy harvest, a Maximum Power Point Tracking (MPPT) algorithm continuously adjusts the converter’s duty cycle by monitoring the PV array’s current–voltage (I-V) characteristics, dynamically shifting the operating point to maintain optimal power extraction even under changing environmental conditions.

Additionally, the DC/AC inverter converter acts as the interface between the sources, loads, and the microgrid.

It is important to mention that the diesel generator in the system serves as a backup (emergency) power source. It will be activated through an automatic transfer with a control system using an advanced energy management system if the renewable generation sources cannot meet the load demand, aiming to reduce pollutant gas emissions and maximize the operation of the system with clean energy. Based on the characteristics and requirements of the microgrid, the components that constitute it are defined [16].

Table 3. Microgrid components and specifications.

Item	Description	Specification	Quantity
1	Photovoltaic panel	JAM60S10 340Wp	4
2	Wind generator	ENAIR 70PRO	1
3	Batteries	UU 12–200 200 Ah/12 V	4
4	Diesel generator	HYLDG12S 10 kW	1
5	Photovoltaic grid inverter	VICTRON 5 Kw	1
6	Wind load rectifier	PRO-GRID	1
7	Wind generator network inverter	WB5000 A 5 KW	1
8	Bidirectional inverter charger	ESS 502 P/W 5 kW	1

provides the description and technical specifications of these components.

The design and evaluation of this electrical microgrid follow a structured methodology composed of six sequential stages, as shown in Figure 6, enabling a technically rigorous and context-sensitive approach. Initially, relevant data are collected regarding load conditions, socioeconomic and geographic characteristics, and the availability of renewable energy resources. This information serves as the basis for estimating load profiles, which are represented through daily and seasonal demand curves. Subsequently, generation and storage technologies are selected and dimensioned according to the load requirements and the monthly average of renewable resource availability.

The next stage involves defining the microgrid topology, including the physical and logical configurations of the system and the interaction among generation, storage, and load components. A feasibility analysis is then conducted, incorporating technical, economic, and social criteria to assess the viability of the proposed configuration. Based on the outcomes of this assessment, design adjustments are implemented to optimize system performance and ensure operational reliability under local conditions. This methodology supports the development of decentralized energy solutions tailored to the needs of vulnerable communities, contributing to sustainable electrification strategies.

3. Simulation Results

In this section, a feasibility analysis for the designed microgrid is presented, which is based on three key factors: social impact, environmental impact, and economic impact.

This analysis aims to establish a guideline on how these factors affect the focus region of this research.

3.1. Microgrid Planning and Sizing

This section includes the Homer Pro tool, which is energy system design software based on renewable energies, but which also allows the coupling of conventional energies such as diesel generators. This software identifies the combination of lowest-cost components that cover the load by simulating configurations and allowing the most suitable one for the project to be chosen. It should be noted that the diesel generator can operate in PRIME mode, which would operate in the system as the main energy source, or in STANDBY mode, which would operate in the system as a backup source in the case of power outages from other generation sources.

Homer Pro software requires certain configuration parameters, both in terms of climate information for the area and the generation sources and inverters to be used, as shown in Figure 7. This figure also shows the configuration and design of the microgrid for the base stations, which is described below. Once the load information for each month has been entered into the Homer Pro software, a load profile is generated, as shown in Figure 7, where the daily profile, monthly profile, average load in kWh/day, average load in kW, annual profile, system efficiency, power and energy averages, and load factor can be distinguished. All of these settings allowed us to understand the limitations, contributions, and functionalities of the designed system [18,19,20]. In addition, after defining the load profile through a temporal analysis of the base station’s consumption, the consumption pattern was identified, which allowed us to establish the load factor, defined as the ratio between the average load and the capacity of the microgrid.

Equation (1) shows the relationship between the load and the capacity of the installed microgrid. This facilitates the identification and establishment of each component of the microgrid. This process involves providing the software with the technical and economic specifications of each distributed energy resource (DER) within the system. This can be seen in Figure 8.

$$K={\displaystyle \raisebox{1ex}{$\overline{Load}$}\!\left/ \!\raisebox{-1ex}{$M{G}_{Capacity}$}\right.}$$

(1)

With the proposed microgrid design, the percentage of renewable energy used is 100%, and the diesel generator shows zero fuel consumption. This is because, under normal conditions, the microgrid can meet load requirements without the diesel generator, which remains in standby or backup mode for the MR. However, the diesel system is only used in the case of backup or emergency in the event of any contingency involving the other renewable resources.

Table 3 provides a detailed breakdown of these data. Regarding the flow of funds invested in the microgrid, the net capital allocated in the implementation year amounts to 104 MCOP, with amounts given in Millions of Colombian Pesos (MCOP). Operation and maintenance over the next 25 years are 2.150 MCOP er year, and equipment replacement due to lifespan in year 25 is around 25 MCOP. The economic analysis of the results provided by Homer Pro indicates the microgrid costs, which are presented in

Table 4. Microgrid investment costs.

Item	Description	Value (MCOP)
1	Net production cost NPC (COP)	126
2	Kilowatt-hour cost LCOE (COP/kWh)	0.009382
3	Net capital cost CAPEX (COP)	104
4	Fuel cost per year (CPO/year)	0
5	Operating cost per year OPEX (COP/year)	2.15
6	Percentage of renewable energies (%)	100

, [21,22].

The microgrid topology design is bus-type, as this allows the microgrid nodes to be connected to the same generation busbar or bus. Information will be sent and received via the bus, and the nodes are responsible for rejecting or receiving the information depending on the application case. For the design of this microgrid, there is one bus and two types of nodes (generation and consumption).

In relation to the communication protocol, taking into account that this is directly linked to the microgrid’s communications, the ModBus protocol is used. This is an industrial protocol that is widely used in electrical applications. It uses a serial communication method between electronic devices and can communicate over distances greater than 50 m. It is capable of establishing server/client communication between smart devices and is used for its simplicity, low cost, very high availability, and compatibility with TCP/IP.

Based on the microgrid requirements, which are defined to electrically supply the base station with a maximum load of 92 kWh/month, and the results provided by Homer Pro, the microgrid was designed, along with the entire communications architecture [23,24,25]. The single-line power diagram of the microgrid, together with the communications and control network, is shown in Figure 9.

It is worth mentioning that the microgrid design is based on the load curve of the base stations, as shown in Figure 10. Considering this load curve and the IECP [3], it was determined that the maximum load the microgrid can handle is 92 kWh/month. This load was used for the entire sizing process and, consequently, forms the basis for the results presented below in Figure 10.

The power production shown in Figure 11 for the microgrid corresponds to the aggregated output of all its integrated generation systems. Additionally, the battery bank can supply power to the load for up to 24 h per month, while the diesel generator can provide power for up to 48 h per month.

These options serve as backup sources when the photovoltaic and wind systems are unable to meet the load demand due to any contingency in the microgrid. Figure 11 and

Table 5. Power generated by the microgrid (overall results).

Month	Load a Attend kWh/month	Power Generated Photovoltaic System kWh/month	Power Generated Wind System kWh/month	Power Generated Battery Bank (24 h) kWh/month	Power Generated Diesel Generator (48 h) kWh/month
January	92	114.24	92.42	3.036	10
February	92	118.32	92.42	3.036	10
March	92	114.24	92.42	3.036	10
April	92	130.56	92.42	3.036	10
May	92	146.88	92.13	3.036	10
June	92	155.04	92.02	3.036	10
July	92	175.44	92.02	3.036	10
August	92	175.44	92.42	3.036	10
September	92	159.12	104.33	3.036	10
October	92	155.04	116.97	3.036	10
November	92	146.88	116.97	3.036	10
December	92	126.48	104.33	3.036	10

illustrate the load to be served versus the power generated by each element of the microgrid, showing that the photovoltaic and wind systems meet the load and generate additional usable power within the microgrid.

The battery bank and the diesel generator reflect low values in the graph because they are sized as backups to meet the load for a duration of 24 and 48 h, respectively.

It is important to note that from Figure 11, it can be deduced that the design of the microgrid meets its main objective, which is to meet a load (base station) of 92 kWh/month.

Figure 12 and

Table 6. Comparison of power generated by the photovoltaic, wind, and diesel generator systems. (Base-Current Stations).

Month	Load to Be Served kwh/mes	Power Generated by the Photovoltaic System kwh/month	Power Generated by the Wind System kwh/month	Power Generated by the Diesel Generator (Base-Current Stations) kwh/month
January	92	114.24	92.42	89
February	92	118.32	92.42	85
March	92	114.24	92.42	88
April	92	130.56	92.42	83
May	92	146.88	92.13	86
June	92	155.04	92.02	89
July	92	175.44	92.02	84
August	92	175.44	92.42	88
September	92	159.12	104.33	85
October	92	155.04	116.97	83
November	92	146.88	116.97	80
December	92	126.48	104.33	87

indicate that the microgrid generates sufficient power to meet the load, exceeding the highest value proposed in this research (92 kWh/month). This allows us to deduce that there is no risk of failing to meet the load at any time of the year, as the current power consumption of the load (base station), which is the same power generated by the diesel generator, is below the proposed value.

Under ideal conditions, the microgrid design can dispense with the diesel generator since it is capable of meeting the load without requiring its intervention.

3.2. Feasibility Analysis

The following analysis is focused on demonstrating the social, environmental, and economic impact of the microgrid design. It also demonstrates how these factors influence the beneficiaries, which, in this case, are the NIZ community and the telecommunications company that provides the mobile phone service.

Social Impact: Considering that one of the key aspects of this research is to improve the quality of life for the inhabitants of the non-interconnected areas of Chocó, it is determined that this goal is achieved, as it significantly enhances the stability of mobile network connectivity. The implementation of the microgrid will provide greater stability in the power supply to the base stations. This stability will significantly reduce the number of failures in the mobile network, which will promote the development of the local community and, consequently, the region, given that communications are currently a fundamental axis of development in any field.

Environmental Impact: The work carried out contributes to reducing pollutant gas emissions into the atmosphere through the generation of electrical energy from unconventional renewable energy sources (URESs), such as solar and wind energy, in this case, thus reducing the use of conventional sources like fossil fuels. Additionally, it is important to consider that the National Government’s regulations include various incentives for the research, execution, and financing of clean energy projects, which generate a dual benefit for both the environment and the companies involved in such research.

Economic Impact: The financial analysis determines the timeframe in which the total return on investment is achieved and the subsequent benefits after that point. Assuming the diesel generator consumes an average of 3 L/h, the consumption and cost of the input necessary to generate electric energy to meet the load over a one-year period are calculated, as indicated in Equation (2).

$$Fuelperyear=3{\displaystyle \frac{l}{\mathrm{h}}}\times 24{\displaystyle \frac{h}{1\mathrm{day}}}\times 30{\displaystyle \frac{1 day}{1\mathrm{month}}}\times 12{\displaystyle \frac{month}{1\mathrm{year}}}=25,920 l$$

(2)

As a result, 25,920 L of diesel fuel is required for the generator to operate uninterruptedly 24 h a day, 7 days a week for one year. To determine the total cost of the generation input, this value is multiplied by the cost of a liter of diesel (COP 2394), as indicated in Equation (3), where COP equals Colombian Pesos.

$$Annual input cost=25,920 l\times 2394=\$62,052,480$$

(3)

It is important to note that within the estimated net production cost (NPC) value, there are 48 h of backup by the diesel generator, which is equivalent to (718,200 COP), a value that will be subtracted in the calculation of the payback time since the microgrid is capable of meeting the load without the intervention of this energy source.

Therefore, the payback time of the investment is indicated in Equation (4):

$$Pyback time={\displaystyle \frac{126,000,000-718,000}{62,052,480}}=2.01 \mathrm{years}$$

(4)

From the above, it can be concluded that the payback period only takes into account the value of the investment and will be achieved in 2.01 years. It is essential to bear in mind that there are additional costs (operation and maintenance) that affect the payback period.

Another aspect to consider is that the O&M of the microgrid during the life cycle of its components (25 years) amounts to 2.15 MCOP, and in year 25, some of these elements can be sold, generating additional income of 27.808 MCOP.

Figure 13 shows the economic impact over a period of 25 years, demonstrating the convenience of the microgrid, and a comparison of the costs with and without the microgrid is presented in

Table 7. Total expenses with and without the microgrid.

Total Expenses Base Stations with Microgrid (Initial Investment + O&M) (MCOP)	Total Expenses Base Stations Without Microgrid (Diesel Generator Fuel + Annual Fuel Increment) (MCOP)
COP 179.750	COP 1551.312

.

From this, it can be deduced that the use of the microgrid is advantageous, as the total expenses are minimal with a reduction of 88.4% compared to the overall costs of continuing to use the diesel generator. Moreover, the microgrid’s multiple sources of generation help minimize or eliminate load shedding, since the load demand is currently being met solely by the diesel generator, which could potentially lead to failures in mobile telephone service supply, affecting both the end-users and the telecommunications service provider.

4. Conclusions

This research sets a precedent as a model to be applied in various non-interconnected zones (NIZs) in Colombia that lack an electric power supply. One of the benefits of the microgrid for telecommunications companies is the reduction in expenses related to the deployment of technical personnel to base stations and the payment of fines for service interruptions.

The proposed microgrid design comprises power generation systems, which significantly reduces failures related to this specific aspect. When one system is unable to meet the load, it is replaced by another system. The microgrid is technically and economically feasible, as it ensures uninterrupted load coverage and reduces the deployment of technical personnel to the base transceiver station (BTS).

The research reviewed during the preparation of this article states that more than 50% of the national territory is still classified as a non-interconnected area. In these areas, telecommunications companies often choose to supply base stations exclusively through power plants to provide their service. Consequently, there are constant electrical failures, causing interruptions in service to the community and economic losses to the telecommunications company.

Some of the NIZs in the department of Chocó were chosen because a study of areas not connected to the national network showed that this department is among the top three NIZs, impacting the quality of life of its inhabitants and the economic development of the region.

At the end of the investigation, it was concluded that the microgrid that is the subject of this project is technically, economically, and environmentally viable, as it provides an uninterrupted power supply and the initial investment will be recouped in a short period of time, which contributes to reducing emissions of gases that are harmful to the environment.

The research presented in this article enabled the design of a BTS microgrid with a maximum capacity of 90–92 kWh/month for telecommunications base stations in the coastal zone of the Chocó department, Colombia. With the assistance of Homer Pro software, the distributed resources and necessary components for constructing the microgrid in these non-interconnected zones (NIZs) were identified.

As a result of the research carried out, the telecommunications company responsible for the service in the NIZ set a precedent as a model to be applied in various regions that lack an electricity supply for this type of station. It is hoped that it can be implemented throughout the country in the future.

It is hoped that this research will encourage the Colombian national government, both at the planning and regulatory levels, to adopt this type of system in order to make the necessary adjustments to future policies, roadmaps, and resolutions.