Examining the Evolution of Energy Storing in the Ecuadorian Electricity System: A Case Study (2006–2023)

Abstract

Ensuring a balance between supply and demand is critical within electricity grids, requiring a supply composition that guarantees consistent service provision in the short and medium term. Between 2008 and 2017, Ecuador’s electricity generation capacity expanded significantly, with an investment of approximately USD 8150 million into harnessing the potential energy of water. This led to the construction of five high-capacity hydroelectric projects by 2017, contributing 33.4% of the sector’s energy output by 2023. However, it is important to note that if installed hydroelectric projects operate as run-of-river plants, with limited reservoir capacity, they can only regulate water use for electricity generation on an hourly basis. As of 2023, these run-of-river plants represent 68.8% of Ecuador’s total hydroelectric capacity within the National Interconnected System (SNI). Consequently, during periods of low inflows, supplementary energy from other power generation plants is necessary to prevent energy crises. This paper addresses the impact on energy storing for electricity generation resulting from the evolution of hydroelectric power plant entry from 2006 to 2023. This aspect has not been thoroughly examined in hydrothermal systems, which primarily focus on potential energy obtained from dams. Our approach involves a statistical analysis of hydroelectric dam reservoir operational levels. We further explore the influence on demand service within Ecuador’s electricity system, particularly during observed energy crises towards the end of 2023.

1. Introduction

The progress of a nation is intricately tied to its ability to meet the demands of its populace, particularly in the realm of electric power generation and its distribution infrastructure, both of which significantly impact various facets of modern life. As the imperative to mitigate carbon emissions grows, there is a mounting shift towards harnessing renewable resources for electricity production. However, these technologies often rely on resources with inherent variability, posing challenges due to their intermittent nature and limited storage capacity. Hydroelectric power generation exemplifies this, as it utilizes reservoirs to regulate the use of stored water’s potential energy, enabling a degree of flexibility in meeting demand over varying timeframes, spanning from daily to seasonal cycles [1,2].

The expansion of the electric power generation system necessitates a balanced approach that addresses both economic and ecological concerns. This entails increasing the utilization of clean and renewable energies, such as hydroelectric power, while concurrently reducing reliance on inefficient thermal generation fueled by fossil resources. Accomplishing this requires the development of modern power grids capable of accommodating distributed generation and active demand management, thus fostering opportunities for innovative products and services.

Given that electrical energy cannot be stored, the growing demand for energy services mandates the construction of new power plants. Depending on the technology employed, this necessitates meticulous planning due to the lead time required for construction before these facilities can become operational [3].

Previous research has revealed that there are very few studies on the optimal functioning of run-of-river hydropower plants. Hydropower plants can be broadly classified based on the quantity of water available, available head, and nature of the load. According to the quantity of water available, hydropower plants can be categorized into reservoir plants, run-of-river plants with pondage, and run-of-river plants without pondage [4].

In [5], the authors focus on optimizing run-of-river hydropower plants, emphasizing their technical feasibility and financial viability. They introduce a mathematical model to determine the optimal design discharge, installed capacity, and number of turbines based on operational rules specific to run-of-river plants. In particular, earlier research focused primarily on the operation of reservoir and cascade systems. These systems primarily explored the operation of reservoirs and associated systems, as well as the development of a mathematical model for optimum reservoir operation, water release timing, and stream flow for power generation [6,7,8,9,10,11,12,13,14,15].

In recent years, research has focused on the energy transition by analyzing the storage capacity which, on the one hand, is benefited by the energy of wind and solar power stations that allow a high availability hourly on the day and, on the other, uses stored water in the periods of low availability of these types of resources through the modeling and simulation of hydropower plants on available statistics of inflows, where the run-of-river hydropower plants are modeled with an average value of inflows [16] using heuristic tools or machine learning [17,18]. These studies do not evaluate the impact of high penetration of run-of-river hydropower generation in the power grid.

In [19], Pereira et al. stated that many hydroelectric power plants in Brazil have large reservoirs, which significantly contribute to the reliability of the energy supply. These reservoirs can be filled during high hydrology periods to store “potential energy” which is used in low hydrological periods to meet demand through low-carbon energy sources. Thus, a large reservoir could control and store energy from inflows over long periods and adjust the energy production of hydroelectric power plants to meet consumption patterns and complement other energy sources. However, due to the limitation of environmental, economic, and social resources and technical restrictions on the exploitation of river basin energy, the construction of new reservoirs with large storage capacities is becoming increasingly difficult. Therefore, most new hydroelectric power plants that are built in electrical systems have a limited storage and regulation capacity, so this type of hydroelectric power plant and associated dam limit the flexibility of the system.

In other countries, reservoirs of electric power generation systems, in addition to storing potential water energy, are used in the control of flooding in the rainy season and the generation of electricity situations that condition the limits of the water level of the dams in the rainy and drought seasons or vice versa. The limitation in the management of reservoirs inevitably turns into energy losses, as has been shown in the impact of South Korea’s electricity system as presented in [20], Kim et al.

In hydro-dominant electric power systems, climatic hydrological variations result in significant seasonal and annual energy variance. The frequency of extreme weather occurrences has increased recently, which has a significant impact on the energy availability in these systems. During dry seasons, the lack of water causes insufficient power to be generated to meet system demand, which lowers system reliability overall, especially if the system has no reservoirs. Fang et al. [21], in order to reduce the negative effects of energy uncertainty and preserve long-term system adequacy, provide a probabilistic strategy to include diurnal, seasonal, and yearly energy management methods in the run-of-river and storage-type hydropower plant planning and operation of a hydro-dominant system, which is used to highlight the effects of reservoir capacity and demand side management on water use and system reliability.

Restrictions on river inflow can make a hydro unit inoperable or only partially operational. The lack of water during the dry season in a hydro-dominant power system might result in insufficient generation to fulfill load demand. When a year is dry, the problem is even worse. In addition, the frequency of extremely unfavorable weather events has increased recently [22]. In [23], Chen et al. evaluate generating dependability using models designed to simulate an energy source with restricted-energy input. There are two primary areas of study and application for the energy management of hydro units owing to energy uncertainty. The first field of research focuses on creating an operating policy for hydroelectric plants based on energy uncertainty to minimize system operating costs. The coordination of hydro units’ periodic energy uncertainty with other forms of generation in a mixed generation system is the second research topic.

During times of low load during the day or during high inflow seasons, these utilities experience energy waste due to water spills. However, they lack the generation capability to keep up with demand during periods of high load or low intake. To preserve or improve system reliability, hydro-dominating utilities must carefully manage and use their water resource. To identify the energy and capacity characteristics of run-of-river and large storage-type hydro plants, models are provided in [24]. The authors suggest ways to let reservoirs fill and keep them filled in the future to maximize hydropower production and lessen the erratic nature of other renewable energy sources. This is because, despite thermal electricity generation’s power dispatch optimization, building seasonally pumped hydropower storage modification dams is imperative to maintain consistent electricity generation [25].

In this context, in [26], Pieron et al. analyze the change in the storage capacity of 47 reservoirs of the Polish power grid, whose main objective is water control to prevent flooding and drought. During the last 48 years, water storage capacity has been reduced by 200 cubic hectometers (Hm³), with water only representing 5% of the capacity of the reservoirs. The energy landscape of Ethiopia is heavily reliant on the availability of water resources. In the event of reduced reservoir capacities due to prolonged drought, there is a risk of transitioning towards utilizing power plants that rely on polluting technologies. While such plants may offer rapid installation, they also lead to an increase in carbon dioxide (CO₂) emissions and environmental impacts [27].

In [19], Pereira et al. analyze Brazil’s electricity system, which holds 12% of the world’s available freshwater, a situation that has enabled it to develop large-scale hydroelectric power generation which plays a key role in its electricity system, accounting for approximately 55% of national supply. With this excess installed capacity, the supply of energy consumption is on the edge of contingency, as the level of their long-term regulation reservoirs can store energy for service consumptions, especially during the annual drought season.

In Latin America, Ecuador is emerging as a significant player in the hydropower sector. The National Master Plan for Electrification 2018–2027 aims to leverage hydroelectric sources to meet over 90% of the country’s power needs. As of the latest official report on Ecuador’s electric sector statistics in 2023, the country’s total generation capacity stands at 5192.30 MW [28]. Despite this capacity, Ecuador faces a severe energy deficit, being unable to meet daily demands, which peaked at 4682 MW in 2023. This shortfall, exacerbated by droughts in river basins supplying 90% of the plants, led to daily power rationing of two to three hours. More details are provided in [29]. This International Renewable Energy Agency (IRENA) report provides an overview of the hydropower sector in Ecuador, including its installed capacity, development potential, and challenges.

In the Ecuadorian electricity sector, from 2007 to 2017, the supply of electricity expanded due to a strong and consolidated public policy of transformation of the energy system. Between 2008 and 2017, investments were allocated to harnessing water resources. Leveraging the country’s unique topography, this investment facilitated the development of five high-capacity hydroelectric projects [30,31]. As the electric grid aims to guarantee a reliable energy supply, it underscores the necessity of maintaining a consistent flow of electricity to prevent potential blackouts. In the case of Ecuador’s hydrothermal system, electricity is primarily generated using both thermal and hydroelectric power plants, with the latter including reservoir-based facilities. However, as of 2023, hydroelectric power plants constitute 19.3% of Ecuador’s total effective installed capacity in the electricity grid [28,32]. In particular, the country faces a complex array of political and economic challenges that are difficult to reconcile consistently. There are tensions between conservation goals and development imperatives, as well as between resource nationalism and the need for foreign financing. Despite these challenges, Ecuador is striving to balance these priorities and progress towards a more sustainable and diversified energy system.

The integration of hydrothermal units within an electricity grid aims to efficiently meet demand by optimizing the utilization of reservoirs. Hence, this is achieved through a balanced participation of thermal, non-conventional generation units (such as solar and wind) and hydroelectric power plants. The objective is to leverage the regulation capacity of each reservoir, allowing for the storage of excess water from the inflow that feeds the dam to meet production targets. In particular, the hydrothermal unit is a power generation unit that utilizes both hydroelectric and thermal energy to produce electricity. These systems combine the generation capacity of hydroelectric plants with that of thermal plants to meet energy demand more efficiently. Consequently, a hydrothermal system is a type of energy generation system that combines hydroelectric power, derived from water, with thermal power, generated from heat, to produce electricity.

The existing literature predominantly addresses two themes: the coordination of hydropower with other generation forms to mitigate energy uncertainty stemming from hydrological conditions, and the optimization of hydropower operations to minimize costs. However, there is limited research on how fluctuations in inflow regulation affect the reliability of hydro-dominant systems amidst the energy uncertainties caused by annual hydrological variability.

This paper delves into an aspect previously overlooked in hydrothermal systems: the impact of the evolution of hydroelectric power plant entry from 2006 to 2023 on energy storing (the term energy storing refers to the capacity of run-of-river hydroelectric plants to regulate water use and thus electricity generation based on the availability of river flows) for electricity generation. In contrast to traditional hydrothermal systems, where analyses have focused solely on potential energy from dam inflows, the contribution of our study is to explore the intricate relationship between hydroelectric plant development and energy storage capabilities. Employing statistical analysis using the software SPSS Statistics version 27.0.1, we specifically investigate how these factors influence on-demand service reliability within Ecuador’s electricity grid. Our research addresses a notable gap by examining the evolving impact of hydroelectric plant advancements on energy storage dynamics. This analysis provides valuable insights into mitigating energy crises, exemplified by the challenges faced by Ecuador’s electricity system towards the end of 2023.

Thus, this study aims to explore and assess the impact of run-of-river hydroelectric systems on energy storage capacity. These systems are considered an “unfirm” resource, meaning they have limited ability to store energy and therefore cannot consistently meet customer demand [33]. Our research concentrates on scrutinizing historical data sourced from various official reports of Ecuador’s electric system. It is worth noting that the methodology we employ is adaptable and can be extrapolated to analyze similar scenarios in different countries.

To provide a more comprehensive view of the current situation, this study conducted an extensive analysis of factors contributing to the decreasing maximum energy storage in Ecuador’s power supply plants. We investigated the historical trends and underlying drivers of this decline, emphasizing the interplay between energy demand growth, hydrological variability, and operational challenges faced by run-of-river hydroelectric plants. Our analysis integrated data spanning from 2006 to 2023, sourced from authoritative entities such as the Ministry of Energy and Mines (MEM), the Energy and Non-Renewable Natural Resources Regulatory and Control Agency (ARCERNNR), and the National Electricity Operator (CENACE). By scrutinizing these datasets, we aimed to uncover nuanced insights into the vulnerabilities and resilience of Ecuador’s electricity system.

The remainder of this work is organized as follows: Section 2 provides a theoretical framework for understanding the analysis performed in this work. Section 3 examines the Ecuadorian electricity system, including its structure, operational challenges, and evolving dynamics. Section 4 analyzes the decreasing maximum energy storing of power supply plants. Finally, Section 5 presents the conclusions of the paper, highlighting key findings and suggesting areas for further research.

2. Methodology and Problem Statement

The methodology employed in this study aims to comprehensively analyze the Ecuadorian electricity system and assess the impact of run-of-river hydroelectric generation on medium- and long-term electrical energy consumption. The approach is structured as follows:

• Data Collection: Data were gathered from authoritative sources, including MEM, ARCERNNR, and ISO-CENACE. The dataset spans from 2006 to 2023, providing a robust temporal framework for analysis.
• System Structure Analysis: An in-depth examination of the Ecuadorian electricity system was conducted, focusing on its composition of 58 generation companies, 19 distribution companies, and 1 transmission company. This analysis included evaluating design considerations essential for ensuring the reliable delivery of electricity with required levels of quality and safety.
• Operational Dynamics and Challenges: The study analyzed the dynamics of energy demand and supply within the system, considering the integration of various energy generation technologies such as hydroelectric, thermal, and non-conventional sources. Special attention was given to operational characteristics presented by run-of-river hydroelectric plants.
• Hydropower Capacity and Storage Analysis: The study specifically focused on hydroelectric power’s participation and capacity in the Ecuadorian electricity system. This included evaluating reservoir storage capacity and the productivity of hydropower facilities in relation to hydropower run-of-river plants, using dam parameters to estimate maximum energy storing, and analyzing implications for energy security.
• Statistical Analysis: Historical data underwent statistical analysis to identify key factors influencing the energy-storing availability of hydropower plants and, with this, the study infers the system’s energy dependency with respect to the stochasticity of inflows. This involved examining trends over maximum power demand and energy consumption due to fluctuating energy supply.
• Impact Assessment: Lastly, the study evaluated the overall impact of run-of-river hydroelectric generation on the energy system, considering current operational conditions and potential future scenarios. This assessment aimed to identify vulnerabilities and propose strategies to optimize energy storing and enhance system resilience.

The methodology implemented is characterized by its simplicity, as it uses historical data and parameters of reservoirs of hydroelectric plants. However, if these are analyzed statistically and through an appropriate process, it allows us to determine the energy storing by the dam and energy flowing from the hydropower run-of-river plants, and with this, it is possible to determine whether energy consumption is supplied with a high share of stochastic energy of inflows to supply the demand. Since consumers find it to have high reliability in its supply, the power grid requires plants that give firm energy, such as thermal plants and energy storing in reservoirs, to be able to use this energy in periods in which inflows are reduced. This is in cases where a hydrothermal system, when it has a high share of hydropower run-of-river plants, is subject to the presence of a blackout.

This study demonstrates a logical progression by systematically collecting data from authoritative sources spanning 2006 to 2023, including governmental agencies responsible for energy regulation in Ecuador. This structured approach allows for a thorough analysis of the data electricity system, focusing on its organizational framework and operational dynamics. Key aspects such as energy demand–supply interactions, statistical trends, and the specific role of hydroelectric power are meticulously examined to understand their collective impact on system reliability and resilience. The methodology culminates in an impact assessment that synthesizes findings to address the overarching problem of how Ecuador’s electricity system copes with increasing demands amidst variable hydrological conditions and aging infrastructure. By linking data collection, systematic analysis, and impact evaluation, the study aims to provide actionable insights for enhancing the sustainability and efficiency of Ecuador’s energy infrastructure.

The Ecuadorian electricity system faces significant challenges due to increasing energy demand, variable hydrological conditions affecting hydroelectric generation, and aging infrastructure in thermal plants. These factors contribute to operational uncertainties and reliability issues, impacting energy security and the country’s economic stability. This study aims to tackle these challenges through conducting a thorough analysis of system dynamics and suggesting strategies to enhance energy management and infrastructure development. The goal is to ensure a sustainable and resilient electricity supply for Ecuador while also providing valuable insights applicable to similar contexts worldwide.

3. Overview of the Ecuadorian Electricity System and Its Operational Challenges

This section provides an in-depth examination of the Ecuadorian electricity system, encompassing its structure, operational intricacies, and the challenges it faces. We delve into the composition of generation, distribution, and transmission entities within the system alongside the design considerations aimed at ensuring the consistent delivery of electricity to consumers with requisite levels of quality and safety. Furthermore, we analyze the evolving dynamics of energy demand and supply, particularly focusing on the integration of various power generation technologies and the consequential impact on system reliability and operational planning. Through the statistical analysis of energy and power data from official sources of the electricity system, it is possible to know the energy-storing capacity of the system and compare it with the evolution of energy consumption to determine whether the demand has a risk of not being supplied because hydropower plants do not have an adequate energy-storing capability, which affects supply in the case of hydrothermal systems.

The Ecuadorian electricity system currently consists of 58 generation companies, 19 distribution companies, and 1 transmission company. The electric system is designed to service its different users with electricity from sources of production to consumers with adequate levels of quality and safety that must be met at every moment of time. Thus, it will have to withstand variability and increase in electricity consumption since, given the different needs of the population in terms of increasing energy; for example, the maximum power demand for the year 2023 was 4810.72 megawatts (MW), representing a growth of 9.6%, and the energy consumption demand of the Ecuadorian National System (SNI) was 35,291.10 gigawatts-hour (GWh) which presents a variation of +6.9% compared to 2022 [34].

Technological advancements and cost efficiencies have enabled the construction of large-scale power generation plants. These facilities require substantial upfront investments and have long amortization periods (typically 25 or 30 years), often preceded by several years of construction (ranging from 3 to 10 years or more). The significant economic risk associated with these infrastructures is typically borne by public entities or private ventures, provided there is an adequate state guarantee to ensure the recovery of investment and operational costs through regulated rates.

Thus, the operational planning of an electricity system consisting of hydropower, thermal, and non-conventional generation plants presents a complexity due to the optimal decision of water use, which depends on temporary coupling, depending on the storage capacity of reservoirs. Conversely, operational decisions are made amidst uncertainty, as exact inflows are often unknown. Instead, only the distribution and probability statistics of these inflows, along with those of non-conventional resources, are available [35].

Figure 1 shows the share of hydroelectric power in the installed capacity of the Ecuadorian electric system. Here, there is clearly inactivity in the growth of the installed capacity of the power grid, despite the natural increase in demand, which is an indicator of a high probability of an energy crisis, as the last hydroelectric power plants entered are low-power plants that are characterized by having a dam but not reservoirs, although they require the dam infrastructure that allows the use of daily flow for generation production [30]. The introduction of a notable power plant occurred with the commissioning of the Coca Codo Sinclair hydroelectric facility, boasting a capacity of 1500 MW by end of 2016. However, it operates as a run-of-river power plant with hourly regulation. Complicating matters further, the river basin where the plant is situated is experiencing high erosion rates, adversely affecting its power generation capabilities [28].

The hydroelectric power plant, with its storage capacity, enables the harnessing of energy from inflows occurring at different times, allowing the system’s independent operator to utilize other electricity production technologies, particularly dispatching thermal units. However, a reduction in storage capacity necessitates the distribution of available resources within a shorter planning horizon, leading to a higher demand for power units to ensure system reliability. Consequently, maintenance becomes primarily corrective rather than preventive.

The previous situation characterizes the Ecuadorian electricity grid, where many thermoelectric generation plants have exceeded 20 years of service life, resulting in low yields, plant factors, and high variable production costs. Generating companies responsible for these units must gradually analyze operational outputs over the coming years, either due to obsolescence or displacement by the incorporation of more efficient, technologically advanced generating units.

In 2022, the unavailable power units of the National Interconnected System (SNI) averaged approximately 1169.8 MW, reaching 1335.4 MW by November, coinciding with the period of depletion (September–February) in the electricity system due to the hydrological cycle of the Amazon basin; the inflow rates in p.u of 2023 are shown in Figure 2, where 75% of the hydroelectric power plants are situated. Hence, the unavailability significantly impacts the SNI, exemplified by the case of the Coca-Codo Sinclair hydroelectric power plant with a capacity of 1500 MW [34].

Given Ecuador’s abundant hydroelectric resources, the expansion of the energy system aims to capitalize on the country’s vast water resources. This is predominantly evident in the proliferation of run-of-river hydroelectric power plants, as depicted in Figure 3 [36]. In this figure, it can be observed that the proportion of such plants stood at 22.4% in 2006, escalating to 69% of total installed hydroelectric capacity by 2023, a figure that has remained relatively stable over the past five years [28].

The configuration of the power generation plants’ supply structure throughout the period, concerning the flow of energy relative to the maximum energy storage in reservoirs for electricity generation purposes, dictates the percentage of the regulation capacity of hydroelectric reservoir plants within the electricity system. This scenario impacts the system’s energy availability during critical periods when inflows are at their lowest. The limited storage capacity of water in hydroelectric power generation further exacerbates this issue, typically spanning only a few hours. Consequently, the energy availability from hydroelectric power plants is contingent upon the flow, which diminishes during critical periods due to factors such as reduced rainfall and elevated temperatures, leading to heightened energy demands from users [37].

For each hydroelectric power plant, it is possible to know its average productivity and the maximum energy storing of reservoir or dam within the plant’s operating limits using [38].

$${EAR}_{max,i}=\left({\displaystyle \frac{S_{max,i}-S_{min,i}}{2.6298}}\right)\ast {\xi }_i\ast h_{65\%,i},$$

(1)

where

$h_{65\%,i}$: Is the water height corresponding to 65% of active storage of i-th dam minus hydraulic losses in meters (m);

${\xi }_i$: Average cumulative productivity in (MW/(m³/s)/m;

$S_{max,i}$: Is the maximum storage level in Hm³;

$S_{min,i}$: Is the minimum storage level in Hm³;

${EAR}_{max,i}$: Maximum energy storing of the hydropower plant.

Notice that (1) delineates the calculation for the maximum energy storing of a hydroelectric power plant, indexed by i, accounting for several key parameters related to the reservoir or dam within the plant’s operational bounds. Moreover, (1) incorporates the average cumulative productivity, ${\xi }_i,$ of the hydroelectric plant, expressed in (MW/(m³/s)/m, which signifies the plant’s efficiency in converting water flow into electrical energy. By synthesizing these variables, the equation provides an estimation of the plant’s capacity to store energy for electricity generation purposes. This analysis underscores the critical importance of comprehending and optimizing these parameters to enhance the efficiency and productivity of hydroelectric power plants, ultimately contributing to the development of a sustainable and dependable energy infrastructure. Additionally, it emphasizes the necessity of implementing effective water management strategies to ensure the optimal utilization of reservoir resources.

4. Results and Discussions

This section delves into the analysis of the decreasing maximum energy storing of the Ecuadorian power supply plants, as indicated in the previous section. It explores the dual role played by these plants: meeting the system’s ever-increasing maximum power demand and fulfilling users’ energy requirements.

As indicated in the previous section, the maximum energy storing of Ecuadorian power supply plants is decreasing. On the one hand, their share in the installed capacity allows them to supply the system’s ever-increasing maximum power demand, and on the other, previous plants’ increasing electricity supply to the system meets users’ energy demand. In this context, Figure 4 shows an analysis of the Ecuadorian hydrothermal system situation. Specifically, this figure shows the relationship between the EAR given by (1) and the energy from the flows of all power plants, denoted as natural inflow energy, as a function of the year. In these results, notice that the energy storing in reservoirs considering the total energy of hydroelectric power plants in 2006 represented 71.2% and was quasi-stationary at an average of 61.9% in the period of 2007–2015; from 2016 to the present, it decreased from 42.1% to only 24.3% of the total energy of the hydroelectric power plants of the system.

Figure 5 illustrates the monthly electricity production in GWh by type of source for the year 2023. The information presents non-conventional renewable energies, thermal, and hydroelectric generation. The prevalence of hydropower in the energy mix has resulted in a significant portion of electricity consumption being sourced from hydroelectric plants. However, as highlighted, this reliance primarily stems from key power units, notably the Coca Codo Sinclair plant (1500 MW). Consequently, during dry spells (October–December), its contribution diminishes, as depicted in Figure 5. To ensure energy security under this operational framework, maintaining target reservoir levels aligned with the hydrological cycle of the basin where hydroelectric plants are situated is imperative. In the case of Ecuador’s system, this corresponds to the Amazon basin, where energy is harnessed from river flows to capture potential energy. Furthermore, Figure 4 also presents a record of electricity production in May 2023, showing the highest production of hydroelectric power plants with 2678.18 GWh, comprising 81.7% of the total share. This coincides with the month of highest inflow in Amazon basin, where the power plants are located within the power system. However, the drought in this basin during the months of October to December, typically peak months for business and commercial activities in the country, led to a decrease in the energy share of power plants to 60.7% on average in this quarter. This situation resulted in blackouts during the period from October to December 2023 and increased the reliance on electricity from thermal power plants and power interconnections with Colombia and Peru [31].

By analyzing the historical expansion of the installed capacity of run-of-river hydroelectric power plants and evaluating the energy-storing capacity of reservoirs within the Ecuadorian hydroelectric power system, we have observed a significant trend. The rise in energy demand within the electrical system, coupled with the hydrological characteristics of basins where these power plants are situated, has led to a reduction in energy storage capacity available for electrical generation purposes. Consequently, this scenario has heightened the vulnerability of the electric generation power system. In tandem with the high levels of unavailability, there arises an urgent imperative to bolster the energy-storing capacity of electric generation power plants. This can be achieved through various means, including the construction of thermal power plants, medium- and long-term hydroelectric projects, and an exploration of alternative energy sources.

At this point, it is important to indicate that the long-term effects of Ecuador’s energy security mostly depend on run-of-river hydroelectric plants, the factors of which include the following:

• Increased Vulnerability to Climate Variability: Run-of-river hydropower plants are highly dependent on consistent water flow, making the energy supply susceptible to seasonal and annual variations in rainfall. During dry periods or droughts, the energy output from these plants significantly decreases, leading to potential power shortages.
• Economic Impact: To compensate for the variability and unreliability of run-of-river hydroelectric plants, Ecuador may need to invest in alternative energy sources, such as thermal power plants, which are generally more expensive to operate. This reliance on costly backup generation can lead to higher electricity prices for consumers and strain the national budget.
• Operational Challenges: Run-of-river hydropower plants have to work in accordance with intermittent nature inflows, which requires advanced power grid management techniques to balance supply and demand. The electric system and the power grid, without sufficient energy storage or flexible backup generation, may face stability issues, increasing the risk of blackouts and reducing overall system reliability.
• Environmental Consequences: Although run-of-river hydroelectric plants are a clean energy source, an increased reliance on thermal power plants during low water flow periods can lead to higher carbon emissions, counteracting environmental benefits. Additionally, the construction of new thermal plants and associated infrastructure can have negative environmental impacts. Furthermore, each hydroelectric plant should maintain an ecological inflow. In other words, downstream of dams, an inflow should be ensured throughout the year, especially during dry periods, to support flora and fauna. Unfortunately, this is not always implemented.
• Need for Infrastructure Investment: Ensuring energy security with predominantly run-of-river hydropower plants necessitates significant investments in infrastructure, including the development of modern power grids capable of accommodating distributed generation, energy storage solutions and enhanced demand management systems.
• Policy and Planning Implications: An effective energy policy and strategic planning are crucial to mitigate risks associated with the reliance on run-of-river hydropower plants. This includes diversifying the energy mix, investing in renewable energy sources like wind and solar, improving the water management system, and enhancing regional energy interconnections to stabilize supply during periods of low hydroelectric production. In addition, one issue with Ecuador’s electrical system is not a lack of regulatory and planning instruments but rather challenges in financing and the billing and payment structure. While users do pay for electricity services, these funds remain with distribution companies. Due to conflicting regulations, some of these companies do not pay for generators and transmission services. As a result, there is insufficient funding for maintenance and the construction of new electric facilities.
• Energy Security Risks: Prolonged reliance on running river plants without addressing their limitations is leading to chronic energy insecurity in all systems. This may undermine public confidence in the energy system, disrupt economic activities, and impede national development goals.

For the above, this study explored the operational dynamics of Ecuador’s power grid, focusing on a high share of energy from hydropower run-of-river plants and a limited share of non-conventional and thermal power plants. There is a predominant dependence on the hydropower run-of-river plants, particularly the Coca-Codo Sinclair hydropower plant, which has a significant influence on the energy mix. Our findings highlighted seasonal variability in hydropower generation due to fluctuations in inflow in the Amazon basin, highlighting its impact on total energy production and reliability during dry periods. Through the statistical analysis of energy storage, we identify key factors that influence power availability and system resilience, thus clarifying the complex challenges facing the Ecuadorian power system’s operations to supply demand.

An impact assessment was conducted to evaluate the broader implications of run-of-river hydroelectric generation on Ecuador’s energy security and environmental sustainability. This assessment involved forecasting scenarios based on current trends and proposed strategies to optimize energy storage capacity and mitigate risks associated with climate variability and infrastructure limitations. By synthesizing findings from our comprehensive analysis, we aimed to provide actionable insights for policymakers and stakeholders to enhance the sustainability and efficiency of Ecuador’s energy infrastructure. Overall, this expanded view not only addresses the current state but also enriches our understanding of the complex dynamics shaping Ecuador’s power system resilience and its implications for future energy planning and policy formulation.

In the context of hydroelectric planning, future trends in the Ecuadorian power system can be examined comprehensively. This involves evaluating the impacts of climate variability on the performance of run-of-river hydropower plants. Given their reliance on consistent water flow, these plants are vulnerable to seasonal and annual variations in rainfall. During dry periods or droughts, the energy output from these plants can significantly decrease, potentially leading to power shortages. Therefore, future planning should focus on diversifying the energy mix to include more energy storage solutions, such as reservoirs, and alternative renewable energy sources like wind and solar. This diversification would enhance the system’s resilience to fluctuations in water availability and ensure a more stable energy supply.

Finally, advanced power grid management techniques and substantial investments in infrastructure are necessary to support the integration of distributed generation and effective demand management strategies. This includes developing modern power grids capable of accommodating variable energy sources and improving water management systems to optimize reservoir usage. Such measures will help mitigate the risks associated with the current heavy reliance on run-of-river hydropower plants. Ensuring energy security will also involve enhancing regional energy interconnections and preparing for new generation and consumption points. By addressing these aspects, Ecuador can reduce its energy insecurity and achieve a more sustainable and reliable power system.

5. Conclusions

The analysis conducted in this study reveals a concerning trend in decreasing maximum energy storing in Ecuadorian power supply plants, which poses significant challenges to the reliability and resilience of the electricity system. To deepen the interpretation of these results, further exploration is needed into the underlying mechanisms driving this decline. Specifically, investigating the impacts of factors such as changing environmental conditions, operational inefficiencies, and evolving energy demand patterns can provide deeper insights into the dynamics at play.

The Ecuadorian electricity system relies heavily on run-of-river hydropower plants, with limited energy storage capacity due to the scarcity of reservoirs. This dependence on precipitation levels makes it challenging to consistently meet energy demand. Therefore, future trends in the Ecuadorian power system should be analyzed within the context of comprehensive hydroelectric planning. Emphasis should be placed on developing projects that provide firm energy and implementing effective demand management strategies to ensure a reliable energy supply for consumers. This approach will help mitigate the risks associated with variability in water availability and enhance the resilience of the electricity system.

The entry of hydroelectric power plants into Ecuador’s energy landscape between 2006 and 2023 has led to a decrease in energy-storing capacity, indicating heightened vulnerability in the power system. This decline is due to increasing energy demand and hydrological factors. The reliance on run-of-river hydroelectric plants poses risks like climate vulnerability, economic impacts, operational challenges, and environmental consequences. Addressing these requires investing in thermal plants, prioritizing hydro projects, diversifying energy sources, improving water management, and modernizing the grid. These strategies can mitigate energy insecurity and ensure a reliable, sustainable power supply.

Additionally, based on the research findings, it is imperative to develop targeted policy recommendations to address the identified challenges and enhance the practical value of the study. These recommendations should focus on strategies to augment the energy storage capacity of the system, such as investing in the construction of thermal power plants, medium- to long-term hydroelectric projects, and exploring alternative renewable energy sources. Moreover, proactive measures to improve water management practices and optimize reservoir operations should be emphasized to maximize the utilization of available resources and ensure a reliable and resilient power supply for future generations. In summary, by delving into the underlying mechanisms driving the observed trends and proposing targeted policy recommendations, this study can provide valuable insights for policymakers and stakeholders in developing strategies to address the challenges facing the Ecuadorian electricity system and ensure its long-term sustainability and resilience.

Finally, this study offered strategic recommendations aimed at mitigating the identified vulnerabilities and enhancing the resilience of Ecuador’s electricity system. These recommendations include but are not limited to: (1) Investing in advanced grid management technologies to better integrate fluctuating renewable energy sources and improve overall system stability; (2) Promoting policies that incentivize energy storage solutions to buffer the intermittency of hydroelectric power during dry periods; (3) Enhancing cross-border energy interconnections with neighboring countries to diversify supply sources and mitigate regional energy deficits; and (4) Strengthening regulatory frameworks to ensure equitable cost-sharing among stakeholders, thereby fostering sustainable investment in infrastructure and maintenance. By aligning these recommendations with our empirical findings, we aim to provide a comprehensive roadmap for policymakers and industry leaders to navigate the evolving landscape of Ecuador’s energy sector effectively.

Future works could explore the broader implications of hydroelectric plant evolution on energy systems beyond Ecuador, considering variations in geographical, climatic, and regulatory contexts. Additionally, investigating the effectiveness of different strategies for enhancing energy-storing capacity, such as technological innovations or policy interventions, could provide valuable insights for improving energy security and resilience in hydroelectric-dependent regions. Furthermore, in future studies, an alternative methodology could involve incorporating dynamic modeling techniques to capture the temporal dynamics of energy demand and supply in the Ecuadorian electricity system. By developing dynamic models, researchers can better understand system behavior and assess the impact of different policy interventions on reliability and planning. Sensitivity analysis could further evaluate model robustness and identify key drivers of system dynamics.

Finally, for future work, we propose incorporating comprehensive and up-to-date data. This will enable a deeper analysis of hydroelectric storage capacities, electricity generation, and consumption trends. By accessing technical data on new hydroelectric plants, including power capacities, construction phases, reservoir levels, and flow statistics, the tool can be enhanced to calculate the energy-storing capacity of all plants. This will support a more robust analysis of system reliability and the development of effective strategies for optimizing energy generation and distribution.