Rural microgrids and its potential application in Colombia

Renewable and Sustainable Energy Reviews 51 (2015) 125–137

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Renewable and Sustainable Energy Reviews journal homepage: www.elsevier.com/locate/rser

Rural microgrids and its potential application in Colombia E.E. Gaona n, C.L. Trujillo, J.A. Guacaneme Laboratory for Alternative Energy Sources Research, Department of Electronic Engineering, Universidad Distrital Francisco José de Caldas, Carrera 7 No. 40B-53 Piso 5, Bogotá, Colombia

art ic l e i nf o

a b s t r a c t

Article history: Received 11 October 2014 Received in revised form 22 March 2015 Accepted 30 April 2015

This paper presents a review about microgrids around the world, particularly analyzing cases installed in rural areas as a solution to the energy access problem in isolated areas. On the one hand, the Colombian case is presented with the aim to describe and analyze the two main problems affecting the electric system in the country: the coverage of electric infrastructure and the energy supply due to El Niño phenomenon. On the other hand, the paper includes the solutions implemented by the national government installing microgrids. Finally, the subsidies offered in Colombia and other countries are shown, giving a comprehensive description of the productive potential of renewable energy, the current legislation and regulations in the country for FNCE promotion (Non-Conventional Energy Sources), and the incorporation to the SIN (National Interconnected System), proposing that there should be focus on training, research and implementation of microgrids in order to allow their deployment in Colombia. & 2015 Elsevier Ltd. All rights reserved.

Keywords: Distributed generation Microgrids Renewable energy sources

Contents 1. 2.

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General topics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1. Microgrid concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2. Types of microgrids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Microgrids worldwide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. Rural electrification: Isolated rural microgrids around the world . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Energy problem in Colombia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. Rural microgrids installed in Colombia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1. Technical standards for the construction and maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2. Experiences of installing microgrids in ZNI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3. Cost analyses of installation and operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. Microgrids prospects in Colombia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1. Policy scenario in Colombia: Subsidies and incentives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2. Productive potential of renewable energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.1. Solar potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.2. Wind potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.3. SHPs potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.4. Biomass potential. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3. Storage and management as key aspects of microgrids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4. Alternatives for starting the deployment of microgrids in Colombia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acknowledgement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

n

Corresponding author. Tel.: þ 57 300 345 9899. E-mail addresses: [email protected] (E.E. Gaona), [email protected] (C.L. Trujillo), [email protected] (J.A. Guacaneme).

http://dx.doi.org/10.1016/j.rser.2015.04.176 1364-0321/& 2015 Elsevier Ltd. All rights reserved.

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1. Introduction More than 1.3 billion people in the world have no access to electricity, and over 84% of them live in rural areas of developing countries. According to Shyu [1], electricity access has a positive correlation with the human development index (HDI) and electricity consumption per capita, being such access critical to human development in emerging countries. In Colombia, the monthly national demand of electrical energy has increased substantially in recent decades, being at an average of 5.166,89 GW h with a real generation capacity of 5.310 GW h [2]. In addition, costs associated with generation, transmission and distribution of electricity have made that the provision of electric service in the ZNI (non-interconnected zones) of the country is mainly performed by means of diesel generation plants, solar panels and small hydro power plants. These areas correspond to 52% of the country, covering 17 regions [3]. The Law 697, issued in 2001 states that the rational and efficient energy use is a matter of social, public and national interest. Under this law, PROURE (Program for Rational and Efficient Energy Use and Non-Conventional Energy Sources) [4] was established and another program such as FAZNI (Financial Support Fund for the Electrification of Non-Interconnected Zones) developed the “Financing of plans, programs and/or projects for the construction and installation of the new electric infrastructure and for the replacement or rehabilitation of the existing, in order to expand coverage and ensure energy demand satisfaction in the ZNI” [5]. Because of this, Distributed Generation (DG) appeared as a technological alternative which allows electricity to be generated as close as possible to the place of consumption [6], without being part of independent systems [7] and, therefore, the use of the socalled microgrids has seen as a feasible solution. A microgrid can be defined as a system characterized by a set of loads, storage systems and small-scale generation sources [8]. Power sources can generally be of various types (renewable sources like photovoltaic or wind generators, and/or generators from fossil fuels), which fulfill local requirements for heating and power generation (Cogeneration) [9]. Microgrids are able to operate interconnected to the power grid in order to exchange energy, meaning that they can serve as either generator or load.

PV Panels

Fuel Cells

Wind Turbine

DC

DC DC

AC DC

DC DC

DC

DC Bus DC AC DC Loads Point of Common Coupling (PCC) Grid

MICROGRID

AC Load

Breaker

Fig. 1. DC microgrid.

Additionally, they can operate isolated, and under such situation, they are responsible for fulfilling the needs of their customers, ensuring quality of supply and possibly the control of some noncritical loads [10]. This paper presents an overview about rural microgrids around the world and particularly in Colombia. The article is divided as follows: Section 2 presents general aspects and types of microgrids, Section 3 shows studies about current status of microgrids established around the world from the research context and also as a solution to energy access problem in isolated locations. Section 4 describes the energy generation problem in Colombia, Section 5 presents the technical standards of installation, experiences and cost analysis of rural microgrids installed in the ZNI. Section 6 shows microgrids perspectives in Colombia such as subsidies, incentives and potential use of renewable energy and finally the paper comes to the conclusions about the most important issues which were covered.

2. General topics In recent years, one of the main priorities on a global scale is the development of alternative sources for power generation, especially renewable sources producing little environmental pollution. While fossil fuels will continue to supply a considerable fraction of energy consumption, energy supply will tend to diversification. Options such as wind and solar energy, renewable biomass and hydrogen will play an important role in the long term and will produce substantial changes in the technological profile for both, the environment and organization of the global energy system [11]. It is clear that from a lack of energy in isolated locations pointof-view, as well as the fact of starting dynamics to employ energy cogeneration using renewable energy, it is feasible to implement interfaces which are able to connect to the power grid in order to transfer energy from renewable sources, as well as to supply loads in case of lack of energy. Taking that into consideration, such interfaces are therefore known as microgrids [12]. 2.1. Microgrid concept A microgrid comprises a portion of the electric distribution system in a medium and low voltage. It includes a variety of Distributed Energy Resources (DER) such as distributed generators and energy storage units, and different types of end users (electric and/or thermal loads), as well as the necessary communication equipment for energy operation and management on real time [13]. The microgrid supplies a range of customers, such as residential buildings, commercial entities, industrial parks and noninterconnected zones [14]. The microgrid has the ability to import and export energy in a flexible way from and towards the power grid from different types of DER. This is mainly achieved in order to control the active and reactive power flow fulfilling the quality requirements demanded by the users it supports, and to manage energy storage [14,15]. A microgrid can be either DC [16]; AC [17] or even a high frequency AC power grid [18]. Additionally, It can work interconnected to the power grid or isolated, from which needs and control schemes are different for each operation mode. When the microgrid is connected to the distribution power grid, there is a backup, and therefore it is possible to feed local loads and deliver energy to the power grid. However, the innovative feature of a microgrid lies in its ability to operate autonomously when there is a power outage in the distribution power grid. This operation mode is called isolated operation, and the microgrid can be considered an “island” with local generators and loads. In this way, users can get

E.E. Gaona et al. / Renewable and Sustainable Energy Reviews 51 (2015) 125–137

a continuous service even when power outages occur in the power grid due to breakdown or maintenance. On the other hand, if there are sags, frequency variations, or failures in the main power grid, the microgrid can be easily disconnected, which means that it can operate isolated from the rest of the power grid avoiding affectations to local loads by such problems. This can be achieved if local energy resources are available, or in other words, if there is energy autonomy. Thus, microgrids not only help continuity of service but also contribute to maintaining its quality [19].

2.2. Types of microgrids Bearing in mind the definition of a microgrid, there are different classification possibilities, depending on certain factors such as the type of generation, loads to supply, physical layout, among others. However, the most evident classification can be done based on electric characteristics, so as to know whether the microgrid uses direct current (DC) or alternating current (AC). A number of different authors such as Shenai et al. [20], Jiang and Zhang [21], Kwasinski and Krein [22] explore the use of DC microgrids. Based on their contributions, it can be established that several generators systems, storage systems and loads are connected to a common DC bus through a converter, where there are loads and storage systems. In the case of AC loads, there is an inverter which ensures adequate power quality conditions. Fig. 1 shows the scheme of a basic DC microgrid: Another classification, depending on the operation voltage level, can be given to DC microgrids. It is possible to work either with voltages resulting from the rectification of a single phase, or Wind Turbine

PV Panels

Fuel Cells

AC DC

Point of Common Coupling (PCC) Grid

DC

DC AC

DC AC

DC AC

AC

AC Bus

Breaker AC DC

AC Loads

MICROGRID

DC Load

Fig. 2. AC microgrid.

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three phase AC systems, or to work with typical DC voltages such as 48 V, used in many schemes and works [22]. Similarly, there are alternating current or AC microgrids. In this type, generation systems and loads are connected through converters to an AC bus. Storage systems and DC loads require converters which are able to adjust the power of the AC bus to their particular characteristics. The bus is connected in a single point to the power grid. To exemplify this, Fig. 2 shows the AC microgrid configuration: Among the AC microgrids there are several classification possibilities depending on the operation voltage, as well as the type of system (single or three phase). Although it is common to find many studies of low voltage systems, it is also possible to find them in medium voltage level, such as the one undertaken by Huang and Yang [23].

3. Microgrids worldwide Microgrids implemented around the world are developed from mainly focused on a research context conducted by countries covering large geographic areas. For example, The United States has done so through projects designed by CERTS (the Consortium for Electric Reliability Technology Solutions) in cooperation with AEP, TECOGEN, Northern Power Systems, S&C Electric Co., Sandia National Laboratories and the University of Wisconsin [24]. In Australia, it has been done through CSIRO Energy Centre in Newcastle [25], and in China through the Chinese National Energy Administrator (NEA) which plans to build 30 microgrid projects during the period of the 12th Five-Year Plan [26], as power grid problems occur due to long transmission distances. However, research on microgrids is not only conducted because of grid problems, but it is also done so as to show the ability to incorporate DERs into it. In a similar way, there have been research studies conducted by countries of the European Union with projects such as the “Microgrids Project”, which was led by the National Technical University of Athens (NTUA) [27] and whose continuation was called “More Microgrids Project”, led again by NTUA [28]. In Japan, the country with more research projects oriented to microgrids [29], such projects have been mostly funded by New Energy and Industrial Technology Development Organization (NEDO). It must be highlighted that these research studies are oriented to maximize the use of the available energy resource when there are electric or thermal loads, as well as to support loads which must be energized at all times (hospitals, data centers, etc.), under high power quality conditions and with the support of DERs. In addition to this, it is necessary to present another perspective about microgrids development since they are the only option for bringing energy to isolated places such as islands or difficult-

Table 1 Examples of microgrids around the world. Source: Based on Planas et al. [32]. Site

Project manager

Place

Country

Columbus Twenty-nine palms, California Hefei Tianjin Newcastle Agria pig farm Mannheim Wallstadt Hachinoche Kyoto Eco-energy

USA USA China China Australia Macedonia Germany Japan Japan

Type Real

Dolan Technology Center General Electric (GE) Hefei University of Technology (HFUT) Tianjin university CSIRO Energy Center More microgrids Project More microgrids Project NEDO NEDO

Structure Test-bed

AC

X X X X

X X X X X

X

X X X

X

X X X

DC

X

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to-access areas, which are non-covered by the interconnected system due to cost reasons, topography or security problems [25,30,31]. Different authors have developed studies focused on presenting a review of the current state of microgrids in the world [19,32]. Table 1 presents a summary of some of those executed projects: Based on data shown in Fig. 3, it can be clearly seen that, in terms of the microgrids installed capacity in the world market, in Navigant Research [33] has identified that for the second period of 2014 there was a total of 4.393 MW, having North America as the market leader with a strong participation of 66%. Only 53% of this capacity is currently in operation, and an additional 2 GW of microgrids are at the proposal stage. Moreover, the majority of microgrids in the United States run on gas. 3.1. Rural electrification: Isolated rural microgrids around the world In the world, although energy generation fulfills the demand in large populations, it leaves the most remote regions of the electrical interconnection system without energy service, this due to costs associated with interconnection, low demand by population density or complicated access to the site. However, government policies in different nations have generated various strategies to fulfill energy needs in these zones, allowing the inclusion of microgrids in order to generate energy. For rural zones of India, in Bhoyar and Bharatkar [34] have identified that DG contributes to the reduction of energy losses and improves power quality, despite the fact that the government policies have established unrealistic goals with regard to the fulfilment of objectives and energy lack reduction [35]. For Africa, in Blyden and Lee [36] and Blyden et al. have made

recommendations [37] focused on evaluating the changes to the concept of autonomous and non-autonomous microgrids in order to provide electricity to local residents, which act as basic units for the system expansion plans. In Vietnam, [38] microgrids topologies are defined for various purposes, showing the case study of a rural area. For rural zones off-grid, Table 2 illustrates microgrids in operation which make use of renewable sources for power generation. As a result of cooperation, renewable energy deployment in isolated microgrids is growing steadily in both developed and developing countries. For example, China and the United States have some small-scale turbines in use, with an estimated capacity of 274 MW and 216 MW by the end of 2012. At least 806,000 small-scale turbines were operating at the end of 2012, exceeding 678 MW (up 18% over 2011) [11]. During 2013, small-scale wind turbines were being used predominantly for battery charging, telecommunications, irrigation and water pumping. On the other hand, the solar PV market had a record year, adding more than 39 GW in 2013 for a total exceeding 139 GW. Even when global investment in solar PV had declined nearly 22% compared to 2012, new capacity installations increased by more than 32% [11]. China increased its capacity nearly one-third of global capacity added, followed by Japan and the United States. In rural areas and islands, hybrid systems such as wind, solar PV, biomass gasification and small hydropower with diesel constitute an attractive option due to declining costs for solar PV and wind, together with reduced costs for battery storage [40].

4. Energy problem in Colombia

Fig. 3. Total microgrids capacity in the world market by region [33].

There are two major problems affecting the electric power system in Colombia: the first one refers to the fact that the electric infrastructure does not cover the entire territory and the second one corresponds to the changes in the precipitations produced by the climatological phenomenon called El Niño. In the case of Colombia, the country needs to provide the necessary electric service to more than two million people, bearing in mind that in the rest of the world, efficient electricity transmission and distribution is a fundamental requirement for providing citizens, societies and economies with essential energy resources, all this happening in a growing demand for electricity. The SIN design has evolved through economies of scale. In large, centralized generation of electrical power and the geographical distribution of generation resources (locations near coalfields and hydro resources). Although the SIN covers the major cities in the country, there are geographical areas which are not connected to the system. Therefore, the ZNI would be those areas in Colombia without grid services of the SIN.

Table 2 Examples of microgrids installed in Rural Zones. Source: Based on Schnitzer et al. [39]. Generation source

PV Biomass

Biomass–diesel Hydro

Capacity (kW)

120 32 50 150 43 32 35 14

Site Town

Country

Koyalapada Samstipur Bhadhi Galyari Bhebra Bara Baharbari Buayan

India India India India India India India Malaysia

Installation year

Hours

2005 2012 2010 2006 2006 2012 2002 2009

6 pm–midnight 5 pm–11 pm (winter)/6 pm–12 am (summer) 5 pm–11 pm (winter)/6 pm-12 am (summer) 6 pm–midnight 6 pm–midnight 6 pm–midnight 6 pm–midnight 24 h (except for dry season, then nighttime only) 24)

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Fig. 4. ZNI Coverage in Colombia. Source: CNM IPSE 2013.

Fig. 4 shows the coverage of the ZNI in Colombia. Nowadays, such zones cover an extension of about 600,000 km2 (52% of the total area of the country) [41], and this comprises about two million people, of which 1.2 million have no access to electricity [11]. Besides this, the percentage of unsatisfied basic needs (NBI) is 71%, whereas for the rest of the country is 28%. This corresponds to more than 544 indigenous reservations, with approximately

840,000 indigenous people of different ethnic groups distributed in the regions of Vaupés, Guainía, Amazonas, Vichada, Putumayo, Guajira, Cauca and Chocó. Similarly, there are 950,000 AfroColombians, mainly in the regions of Chocó, Archipelago of San Andrés, Providencia and Santa Catalina, Valle, Bolívar and Cauca. The national government, through the IPSE (Institute of Planning and Promotion of Energy Solutions for Non-Interconnected

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Composition of SIN Generation 5,70% Hydraulic 41,835.94 Termic 16,838.63

27,10%

67,30%

Lowers and cogenerators 3,522.01 Fig. 8. Power reserve margin of the Colombian system [2].

Fig. 5. Composition of SIN generation in Colombia (2013). Source: XM 2014.

Fig. 6. Effective SIN Capacity (December, 2013) [3].

Fig. 7. Projected power demand and installed capacity [2].

Zones), has installed hybrid microgrids in ZNI as a solution to the electricity supply problem in rural zones, developing pilot projects in innovation centers with the objective of evaluating technologies for energy generation, acquisition of knowledge and experience in the implementation and adoption of these technologies [42]. Since most of the SIN energy generation in Colombia comes from hydroelctric generation (67%), this is annually affected by climate variability in the country, especially with El Niño phenomenon. Therefore, the reservoirs level decreases and the use of fossil fuels increases to compensate the hydro generation deficit.

Additionally, the remaining 33% is obtained from thermal power plants, with some limited participation of PCHs (Small Hydro Power Plants), Photovoltaic and Wind Power Systems. On the other hand, and considering the ZNI, energy generation is mainly derived from diesel power plants, solar panels and PCHs [3], consequently, it can be seen that shared generation with FNCE improves microgrids autonomy. Fig. 5 compares, the proportion of energy generated in Colombia in 2013. Colombia’s total installed power capacity accounted for 14.558 MW by the end of 2013, comprising 64% of hydric resources, 31% thermal and 5% of minor resources and cogeneration [43]. In the ZNI in particular, 92% of power generation corresponds to diesel plants and the remaining 8% to FNCE such as photovoltaic systems and biomass [3]. Additionally, although the capacity in this zone composed only 165 MW, FNCE were able to provide 192.4 MW to the SIN, accounting for 1.4% of the total installed capacity in 2008. Fig. 6 compares effective capacity of SIN in 2013. The UPME (Mining and Energy Planning Unit) conducted a projection of the possible evolution of the country peak demand in 2013, taking into account the current available capacity and future capacity of the generation system [2]. Fig. 7 shows that the installed capacity was higher than the power requirements the system demanded in all scenarios, by means of keeping availability indicators of existing plants. However, the annual energy demand reached 60,890 GW h [43]. Although the capacity in projections in Fig. 7 was considerably high, Fig. 8 clearly reveals a reduction in the reserve margin of the electric system, which will decrease by about 18% in 2021 (high scenario). From 2022 onwards, the reduction would be even more significant, if new generation projects in the country are not taken into consideration. In order to counteract the effects of reduction in the reserve margin and the country energy requirements for the year 2022, the UPME formulates different expansion scenarios of the electric system including autonomous supply options, FNCE incorporation, different demand scenarios and future interconnection with neighboring countries. One of the proposed scenarios for FNCE incorporates three wind parks, which will be located in the Guajira region, generating 100 MW each, two 50 MW geothermal plants in the central region of the country and minor solar energy plants. The commissioning of these projects is expected to be established in the years 2020, 2021 and 2023, respectively, with a surplus sale potential to the SIN of 140 MW from cogeneration plants. As a result, the solution will strengthen the microgrids infrastructure as an alternative generation scheme to SIN in difficult-to-access areas.

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5. Rural microgrids installed in Colombia

5.2. Experiences of installing microgrids in ZNI

5.1. Technical standards for the construction and maintenance

The most successful cases of microgrids installed in ZNI in Colombia are: Titumate in Chocó and el Cardón in Guajira. Titumate has 70% of power generation based on FNCE (Solar PV) and 30% based on Diesel. Furthermore, the average time of operation with FNCE is of about 18 h, whereas with Diesel it is of approximately 6 h. Moreover, in La Guajira, the microgrid located at the Cardón is becoming part of the SIN instead of continuing being a ZNI microgrid. The system interconnects the Cardón (Wind–Solar PV) and Cabo de la vela (Wind–Solar PV) through a 13.2 kV circuit from the output of the substation Puerto Bolívar (Cabo de la Vela) and Meera (El Cardón) benefiting a population of about 3000 residents. On the other hand, there are several zones in the ZNI without electric service supply or zones in which the electric service is provided intermittently due to different reasons, such as the deficiencies in infrastructure for the distribution of energy, no enough resources allocated for power generation and problems of public order which may prevent or hinder the service. The productive potential of microgrids for supplying energy to the external power grid have been developed in academic contexts by Hernandez [44], based on PV power source. Such system was tested at the Universidad Nacional de Colombia locations. The design was based on traditional, residential energy consumption (315 kW h). Apart from that, Hernández et al. has tested another PV grid-connected system in [45].

Currently, no technical or legal definition of a microgrid can be found in the Colombian energy regulations, neither technical standards for its construction and maintenance. However, there are technical requirements for photovoltaic panel installations, which must follow the Colombian Electrical Code NTC 2050, particularly section 690, and the RETIE (Technical Regulations of Electrical Installations) for maintenance and operation. Moreover, there are several technical guides such as: NTC (Colombian Technical Standards) NTC 2775 (Photovoltaic Energy, Terms and definitions); NTC 2883 (Photovoltaic Energy, Photovoltaic Modules); NTC 2959 (Photovoltaic Energy; Guidelines for characterization of batteries for storage energy in photovoltaic systems) and NTC 4405 (Photovoltaic Energy, Energy efficiency, Evaluation of the efficiency of photovoltaic solar systems and components). The energy generation installed by IPSE in ZNI is mainly composed by Solar Photovoltaic (PV), Wind Turbines (WT) and Diesel power plants in order to supply energy to four groups of loads. The first one relates to street lighting; the second corresponds to medical equipment in healthcare centers, the third one concerns schools with the use of computers, lighting and audiovisual equipment, and finally in coastal zones with refrigeration systems for food storage. Table 3 shows the list of microgrids installed by the IPSE currently operating in ZNI.

Table 3 Examples of microgrids installed in ZNI of Colombia. Source: Based on IPSE [3]. Generation source

Solar PV–Wind–Diesel Solar PV–Diesel

Solar PV–Wind PCH

Capacity (kW)

Site

425 545 165 4.32 36 3.6 2.9–5 2780 1875 55

Town

Department

Nazareth Isla Fuerte Titumate Pueblo Nuevo Barrancominas La chorrera Cerro la Teta Flor del paraíso Bahía Solano El salado La encarnación

Guajira Bolivar Chocó Guainía Guainía Amazonas Guajira Guajira Chocó Antioquia Antioquia

Installation year

Average monthly delivery service

2010 2008 2011 2011 2011 2011 2011 2011 1999 2000 2007

13 h, 15 min 8 h, 55 min 10 h, 14 min 6 h, 41 min 5 h, 17 min 7 h, 21 min 23 h, 57 min 22 h, 22 min 23 h, 11 min

Table 4 Rural microgrid cost in ZNI.Source: Base on CORPOEMA [46]. Capital expense

Equipment

PV

Renewable source Regulator Battery bank Inverter

Wind

Capacity

Units

Price (USD$/kW)

%

Capacity

Units

Price (USD$/kW)

%

110 10 1440 300

Wp A Wh W

2318 552 3298 404 569 4800 1829 1652 826 16,248 – 90,909

14 3 20 2 3 30 11 10 5 100

400 25 5400 500

W A Wh W

3815 655 3067 191 513 2527 1431 1464 732 14,393 – 25,000

27 5 21 1 4 18 10 10 5 100

Spare parts (5%) Installation Transport Project Management Contingency Total Operation Maintenance Currency was converted according to the month specified below. US$ 1¼ 1800 Colombian Peso (December 2012).

Annually Annually

Annually Annually

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On the other hand, the rural microgrid project installed in Nazareth (Guajira) did not prove successful due to technical problems with the mechanical malfunction of the Wind Turbine and the wrong calculation of the batteries bank capacity, as well the lack of training of indigenous communities in equipment operation. However, the system is currently working with Solar PV and diesel sources. 5.3. Cost analyses of installation and operation Rural Microgrids, installed in ZNI areas are more sensitive to cost variations due to the unique nature of most projects, which results on less standardized design processes and special deployment conditions. Consequently, results with regard to price have increased from 1.5 to 1.7 times, compared to similar microgrid

projects which were located in an easily accessible site. Table 4 shows approximated cost analysis for two inaccessible populations in ZNI area. In such areas, installation costs are classified by equipment, installation, project management, operation and maintenance. However, due to the site remoteness, additional costs need to be considered such as remote equipment transportation, remote crane operation and spare parts which may be available on site. In these zones, the distributed sources are hybrid systems such as PV–Diesel, Wind–PV also PV–Wind–Diesel systems. In all these cases, the systems elements are WT DC/AC, battery bank and converters. The microgrid supplies electricity needs such as lighting, radio and TV to rural families. The wind system (400 W) installed at Nazareth (Guajira) is located in the northern part of the country. The wind energy

Table 5 Rural microgrid cost around the world. Source: Base on Li et al. [47], Bhattacharjee [48], Ramli [49], Fazelpour [50] and Arriaga [51]. Region

Cost/ Technology

Diesel ($/kW)

Solar PV ($/kW)

Small WT ($/kW)

Flywheel ($/kW)

Converter ($/kW)

Battery Bank ($/kW h)

Total Cost ($ /kW)

%

Urumqui (China)

Capacity Equipment O&M ($/kW/ yr) Replacement 20073 Capacity Equipment O&M ($/kW/ yr) Replacement 14,825 Capacity Equipment Installation O&M ($/kW/ yr) Replacement 10763 Capacity Equipment Installation O&M ($/kW/ yr) Replacement 15500 Capacity Equipment Installation O&M ($/kW/ yr) Contingency

– – –

5 kW 5000 3

2.5 kW 5000 50

– – –

1 kW 700 10

6.94 kW h 1100 10

11,800 73

58.8 0.4

– 100 – – –

2500

4000

–

700

1000

8200

40.9

1.5 kW 2800 0

1 kW 4000 0

– – –

1.5 kW 700 0

1394 kWh 310 5

7810 5

52.7 0.0

– 100

2800

3200

700

310

7010

47.3

1521

1800

53.2 0.0 0.4

Tripura (India)

Makkah (Saudi Arabia)

Kish Island (Iran)

Kasabonika Lake Firs Nation (Canada)

500 kW 800 – 16

400

10,569 kWh 1200

10

– – – –

20

–

5721 0 46 4996

46.4

46.8 0.0 10.6

1521 100.0 620 kW 1000

1500

–

400

375

1200

1 kW 3500

20 kW 750

55 kW 900

9645 kW h 1100

1590

25

25

– – – –

0

10

7250 0 1650

900 100 – – – –

3200

600

–

800

1100

6600

42.6

200 kWp 3700 1840 42

50 kW 7289 1709 335

– – – –

– – – –

4.42 kW h 348 48 13

11,337 3597 390

62.8 19.9 2.2

–

1019

1632

–

–

80

2731 18,055

15.1 100.0

Table 6 Current Policy context.Source: Based on [53–57] and [58]. Name

Regulator

Description

Public Law 697 of 2001 (URE) CREG Resolution No. 071 issued in 2006. CONPES 3453 (6-Dec07) CREG Resolution No. 148 issued in 2011 MME Resolution No. 180919 issued in 2001 Public Law 1715 of 2014

Colombian Congress (Rational and efficient use of energy URE) Ministry of Mines and Energy

Law of the rational and efficient use of energy (URE)

CREG

It defines the compensation methodology for the reliability charge in the wholesale energy market and includes small hydro plants Whose objective is focused on power generation replacement based on fossil fuels for renewable energy technologies, wherever possible It defines the methodology for determining how the firm wind energy plants can participate in the compensation scheme of reliability charge It refers to the Implementation of the program for the rational energy use

Colombian Congress

It promotes the development and use of FNCE in the SIN

National Council for Economic and Social Policy (Consejo Nacional de Política Económica y Social)—Conpes CREG

E.E. Gaona et al. / Renewable and Sustainable Energy Reviews 51 (2015) 125–137

conversion system used for cost analysis is the WT S/W Air X 400 W, battery AGM (Trojan T105), 6 V, 225 A h, inverter and MPPT converter. The total installation cost would be approximately $ 2527 US$/kW. Additionally, remote transportation costs are estimated at $ US 2.05/kg from Barranquilla (Atlántico) to Rioacha (Guajira). Spare parts are considered to be 5% of the equipment and installation cost ($ 513/kW). Hence, the total estimated cost for a turnkey Wind installation at Nazareth is $ 14,393/kW. On the other hand, the Photovoltaic (PV) system (100 Wp) installed at Cravo Norte (Arauca), which is located in the northwest part of the country, has lower installation costs per kW in comparison with small turbines. As a reference, the estimated PV equipment cost is $ 6572/kW, which accounts for the Si mono panels, the MPPT converter, battery and inverters, and finally the connection equipment. The installation cost is calculated using the service rates set at $ 210/day of an electric engineer and $ 50.6/day of an assistant electrician apprentice ($ 2369/kW). Remote transportation cost is estimated at $ 2.22/kg. As a result, the estimated cost for a turnkey PV installation at Cravo Norte is $ 16248/kW. The maintenance cost is estimated taking into account the rate salaries of an electrical engineer, a two technical operators ($ 10,000/year), which in both cases is equal. However, the WT has lower maintenance cost per kW when compared to PV system due to the power delivered. Finally, both cases do not involve operating cost since the customer is trained. Table 5 shows the cost for some examples of rural microgrids projects around the world, taking into consideration technology, installation, M&O and replacement. Such data was collected for techno-economic analysis as well as for the design of a case study involving different hybrid microgrid projects in rural and remote communities.

6. Microgrids prospects in Colombia The Colombian power system has been developed under the mature and traditional centralized generation scheme. Such system is based on large generating stations and centralized control, which is technically optimized for regional power adequacy. Its limited cross-border interconnections and differing regulatory and commercial frameworks are barriers for the introduction of new technologies for renewable energy sources (RES) and new proposed distribution structures such as microgrids. Current power grids serving Colombian consumers have evolved over more than a hundred years as consumers have grown all around the world. Currently, social problems and infrastructure costs in Colombia have limited the provision of electric service to only 97% of the population [11]. The Colombian market liberalization, which began with Law No. 142 issued in 1994, has allowed supplying electric service to more users. Thus, until 1993 the cost of electric investment had had a large percentage of the Colombian debt and the big hydro power dependence of the electricity market had led to rationing and a delay in the development of the Colombian power system [52]. Currently, the electric market has been liberalized, and plans include reducing the hydro power dependence. 6.1. Policy scenario in Colombia: Subsidies and incentives The microgrids implementation is only possible in ZNIs under the energy policies in Colombia. The access for generation plants of less than 20 MW is not allowed, this due to the regulated electricity market. Besides this, the electricity in ZNI is considerably expensive because of the inherent conditions in such areas and a low ability to pay for the service. Therefore, the National

133

Government provides subsidies for lower rates, and that can be seen, for instance, in the Resolution 180961, issued in 2004, in which the MME (Ministry of Mine and Energy) defines the factor subsidy granted to users by reducing the charging rate. Additionally, the Law 732 issued in 2002, established that the indigenous settlements in vast rural areas will receive special treatment in terms of grants and contributions of public services, and the Law 633 issued in 2000 provided the sources and destination of resources by the FAZNI. The Fund has been and maintained primarily through the contributions made by the ASIC (Exchange System Manager Commercial) in the Wholesale electric market. Table 6 shows the main policies and laws in the context of the Colombian energy context, in relation to the ZNI and FNCE. First of all, the Law 697 (2001) or the Law of Rational and Efficient Energy Use (URE), give the guidelines for implementing FNCE sources in electricity generation with incentives for ZNI rural areas. Moreover, the Law 788 (2002) provides tax exemptions for projects which can contribute to energy efficiency, activities or assets that generate certified greenhouse gas reductions. Furthermore, it ensures income tax reduction from the sale of electricity generated from biomass, wind and agricultural waste, as well as exemption from the value added tax on imports of equipment and machinery. Apart from that, by means of Commission of Regulation of Energy and Gas (CREG) Resolution 091 issued in 2007, an incentive to the implementation of renewable energy technologies in ZNI was granted, recognizing a risk premium equivalent to 3.5 points technology cost per capita. As established by resolution 180919, the MME determined the implementation of the PROURE. This resolution establishes participation goals for both the national grid and for ZNI, as well as other targets for energy efficiency in different demand sectors. The National Energy Plan (2010–2030) presented by the UPME, promotes the use of renewable energy sources RES, especially for ZNI and electricity customers in isolated electricity networks. Considering the aforementioned, microgrids are presented as a solution to include those sources in the grid. With that I mind, the feasible energy sources for microgrids in Colombia can include photovoltaic, wind, biomass, small hydro plants (PCH), micro turbines and internal combustion engines ICE. The law 1715 (2014) has been enacted with the aim to establish the legal framework and instruments for the promotion and use of FNCE, especially those from renewable sources, although its integration in the SIN and participation in the ZNI modified the electricity market. In addition, this law has been created to encourage investment, research and development for the production and use of energy from FNCE. What is more, it has provided some incentives for investors such as income tax reduction of about 50%; exemptions in the value added tax in equipment and national services, tariff exemptions in import equipment and materials, annual depreciation rate of about 20% for FNCE projects. By contrast, Table 7 shows a comparative group of policies oriented to microgrid projects all over the world. The overriding objectives of the National State energy policy are mainly aimed at ensuring sustainability, competitiveness and security of supply, requiring a coherent and consistent set of policies and measures to achieve them. The existing conditions of the electricity market in Colombia have achieved market liberalization and growth and, in a similar way as in Japan, the market has shown an increasing number of participants, as well as private financial participation. It is important to incorporate the development of new energy sources, cleaner technologies and technological progress (power electronics and telecommunications). In the second place, quality standards and appropriate levels of coverage are also needed. Although technology has been developing fast and has therefore evolved rapidly as well as the international policies in

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Table 7 Microgrid International Policies. Source: Based on IPSE [3], Romankiewicz [59] and KPMG International [60]. Country Japan

Renewable energy/microgrid policies

Other policies, incentives and subsidies

Highly dependent on fossil fuel imports, partially liberalized RPS (2002), feed-in tariff (2012) Interconnection Guidelines electricity market, unofficial nuclear phase out (Fukushima), (1995); electric law amendments allowing IPP sand partial liberalization (1995, 1999, 2003); New Energy Basic Plan(2010) 25% reduction in greenhouse gas emissions by 2020 The Feed-in Tariff (FIT) rate for the period from 1 April 2014 to 31 March 2015 is:  Solar: 34.56 Japanese yen (JPY)/1 kW  Wind: 23.76(JPY)/1 kW

Singapore Singapore Initiative in New Energy Technology (SINERGY) (2007)

30% special depreciation in addition to ordinary depreciation Tax credit (7% of acquisition costs) Nearly entirely dependent on fossil fuel imports, 16% below BAU greenhouse gas target for 2020

15% non-fossil target for 2020 (2009). Renewable energy law 50 GW CHP target, natural gas targets, feed-in tariffs for (2006), 100 New Energy cities, 30 microgrid pilots (2011) Draft renewable energy, 40–45% carbon intensity reduction target for 2020 (below 2005 levels) management methods for distributed energy (2011) 50% refund of value added tax (VAT) is paid on the sale of wind power 50% refund of VAT is paid on the sale of self-produced photovoltaic power from 1 October 2013 to 31 December 2015 Canada Green Energy and Green Economy Act of Ontario, Ontario feed- Western Climate Initiative,17% reduction in greenhouse gas in tariff, British Columbia Clean Energy Act (2010), Renewable emissions by 2020 off 2005 levels for participating provinces; national clean energy standard—90% from hydro, nuclear, Energy Standard Offer Program (2006) wind, solar, or CCS by 2020 (from current 77%) There are no feed-in tariffs or quota obligations at the federal level but they are implemented in some provinces US 30 states with RPS, 44 states with interconnection policy, 44 Development of CERTS technology, DERCAM and microgrid states with net metering policy software, IEEE 1547 standard development, proposed 80% clean energy goal by 2035, 17% reduction in greenhouse gas emissions by 2020, off 2005 levels Product Tax Credit: Wind, biomass and geothermal: USD cents (ct) 2.3/kW h Other: ct1.1/kW h Mexico Law for the Development of Renewable Energy and Energy (2013) increase non-fossil fuel based power generation to 35%. Transition Financing (LAERFTE). (2008) 100% deduction incentive for taxpayers who carry out investments in renewable energy equipment, cogeneration systems of efficient electricity. Chile Law 20,257. Non-Conventional Renewable Energy (NCRE) Strong renewable resources (solar, geothermal, wind), 20% RPS of 10% by 2024 below BAU greenhouse gas target for 2020 Colombia Law 1715 (2014) Integration of FNCER in the SIN Incentives for investors such as income tax reduction of about Law 788 (2002) 50%; exemptions in sale taxes equipment and national services; tariff exemptions in import equipment and materials; annual depreciation rate of about 20% for FNCE projects. Argentina Law 26,190 National Promotion Regime Power Generation Anticipated (VAT) refunds for the new depreciable property from Renewable Sources (2009). RPS of 8% by 2016 (except for automobiles) included in the project. Accelerated income tax depreciation Subsidies at national level:  Wind:0.015 Argentine peso (ARS)/kW h  Solar: 0.9 ARS/kW h  Hydro for less than 30 MW installed capacity: 0.015 ARS/ kW h  Other: 0.015 ARS/kW h China

renewable energy they have not progressed in the same way in the Colombian context. Despite the fact that the recent Law 1715 has laid down the pathway for the use of renewable source in microgrids, the customers who are not covered and the great area without electricity in Colombia represent a major challenge and a crucial factor which need to be considered as the ideal scenario for the development of strategies for managing the power generation and its rational use. It is essential that such trends take place in a coherent way addressing technical, commercial and regulatory factors, so as to minimize the risk and allow business decisions to be made by companies in a stable environment. Future grids must provide all consumers with a highly reliable, cost-effective power supply, fully exploiting the use of both large centralized generators and smaller distributed power sources. In order to achieve these objectives, customers, providers,

Agencies involved NEDO; METI

Energy Market Authority, An STAR Inst. of Chemical and Engineering Sciences NEA; Chinese Academy of Sciences: Inst. of Electrical Engineering

Natural Resources Canada, NSERC Smart Microgrid Network

DOE, CEC, DOD, NREL

ERC,SENER

CNE MME, IPSE, FAZNI

CAMMESA, EPSE

researchers and lawmakers must all get involved in the development of electricity policies, technologies and solutions. It is clear that the current power system needs to be adapted so that it can manage new connections of multiple generators and user demand without affecting the power quality service [61]. Advances in simulation tools will greatly assist the transfer of innovative technologies to practical application for the benefit of both, customers and utilities. Developments in communications, metering and business systems will open up new opportunities at every level of the system and they will enable market signals to drive technical and commercial efficiency. Furthermore, as new technologies allow interacting with the present networks and any of the actual generators, the main change in the grid must be focused on a bidirectional power flow. At present, it works in a unidirectional way, taken from the big power sources to the

E.E. Gaona et al. / Renewable and Sustainable Energy Reviews 51 (2015) 125–137

2.5 2 1.5 1 0.5 0

Guajira

Costa Atlántica

Orinoquía

Amazonía

Andina

Costa Pacífica

Kilowatt per hour per square meter per year (KWh/m2/yr) Fig. 9. Areas with the highest potential for solar energy in Colombia [65].

3500

135

6.2.2. Wind potential Wind regime in Colombia is considered among the best in South America. The coastal regions of Colombia have been classified under class 7 winds, which means they can reach 10 m/s [68]. The annual wind energy density varies between 1 kW/m2 and 1.331 kW/m2 at 20 m high, whereas it goes between 2.197 kW/m2 and 2.744 kW/m2 at 50 m high [63]. Fig. 10 shows the potential of wind energy in regions of the Atlantic coast of Colombia. If only the estimated wind potential in the Guajira region is considered, that would indeed represent an important figure of 24.8 GW. Nowadays, the country has an installed capacity of 19.5 MW of wind energy in the Jepirachi park, located in the Guajira region. Since 2012, the JEMEIWAA KA’I SAS wind project, situated in the north of the country, has been registered and operates with a capacity of 100 MW [67].

6.2.3. SHPs potential Currently, Colombia has a total of 197 PCHs, with an installed capacity of approximately 168.2 MW [67]. With regard to hydric resources in Colombia, the average flow of the 5 main watersheds of the country is 66,440 m3/s, which represents a potential of 93,085 MW, from which 25,000 MW has been estimated as potential for small hydro power plants.

3000 2500 2000 1500 1000 500 0 Cabo de la Vela

San Andrés Providencia

Rioacha

Soledad

Cartagena

Valledupar

Kilowatt per hour per square meter per year (KWh/m2/yr)

Fig. 10. Power wind potential in regions of the Atlantic coast of Colombia [66].

consumer centers. Taking that into account, the proposed microgrids might evolve into a bidirectional user in the specified scenario. 6.2. Productive potential of renewable energy Colombia has different kinds of renewable resources such as solar, wind, PCH and biomass, which can be used in the ZNI for building a microgrid. The Institute of Hydrology Metering and Environmental Studies (IDEAM) and UPME published the Solar Radiation Atlas [62] and Wind Atlas [63] in 2006. In addition, there have been advances in the development of Atlas about hydropower [64] and biomass potential for electric energy generation. 6.2.1. Solar potential The Guajira is the region with the highest solar radiation levels and one of the sunniest regions in the country. However, not only that state but also the whole country shows untapped solar energy potential, which reaches a multiyear daily average close to 4.5 kW h/m2 [62]. The installed solar capacity in the country is of about 6 MW, in which 57% is used in rural areas and 43% in road lighting, respectively [65]. Fig. 9 presents the average of solar energy availability by region in Colombia. The application of solar systems is more suitable in rural areas, where isolated areas can be found and their interconnection to the power grid is rather expensive. Since 2012, the project for the solar energy plant AWARALA has been registered, having a capacity of 19.5 MW [66]. Similarly, the Renewable Energy Colombian Association (HACER) estimates nearly 1 MW of photovoltaic power which is currently installed and interconnected to the power grid in pilot projects developed by self-generators [67].

6.2.4. Biomass potential Regarding biomass, Colombia has the potential for using it as the basis for producing alternative energies from bananas, coffee pulp and animal waste. In addition, it has been suggested that biogas can be obtained from anaerobic treatment in bananaproducing areas. Moreover, and in relation to coffee and its potential, this generally comes from the waste, which is nearly 40% of the total wet weight. Taking into account the aforementioned factors, it is estimated that about 85,000 TOE/year would produce 190 million m3/year of biogass generated from coffee plantations, equivalent to 995,000 MW h. The annual potential of biomass energy in Colombia is of approximately 16,260 MW h per year and it is distributed as follows: 658 MW h/year of biodiesel, 2640 MW h/year of bioethanol, 11,828 MW h/year of agriculture residues, 442 MW h/year of forestry plantations residues and 698 MW h/year of natural forest residues [69]. However, due to the low energy density and transportation costs involved in carrying them to processing plants, it is not an economically viable alternative [67]. 6.3. Storage and management as key aspects of microgrids Electricity storage is the most important challenge the electric power system faces nowadays. The development of power systems has generally been established in alternating current (AC). Nevertheless, it is necessary to convert AC into DC as the latter one provides the most viable storage capacity. According to Liserre et al. [70], the development of storage technologies allows greater storage capacity of electric power in DC, and power electronics therefore permit its use in the current distribution systems Recent studies in López [71], with concerning the effect of storage over the SIN in Colombia, show the significant impacts of energy storage on the overall system. However, since the microgrid concept was introduced, storage can now be defined as the management reference inside the microgrid which allows it to be perceived as an operator within the system, which decouples effects of variations in RES or small energy sources. This may be proposed as a distributed storage model to the power system, or a managed storage inside the microgrids in a sub-level management within the SIN.

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According to Prodromidis [72], there are a number of improved combinations of storage technologies with important capital cost and limited efficiency. It is worth pointing out that the energy storage system is still evolving, and its autonomy and maturity have not yet been fully achieved. The most promissory technologies for energy storage in Colombia are hydro-pumping, being followed by battery technology. With coordinated communication, the storage system may allow local energy management and full integration of DG and RES, with large-scale central power generation. 6.4. Alternatives for starting the deployment of microgrids in Colombia Microgrids implementation should be a gradual process for which it is necessary to work in the three following areas: Training: Which means new technologies, economic challenges, increased energy and service quality requirements, as well as enough information to meet the challenges in the context of sustainable development and social knowledge. Research: It is important to note that the particular geographical characteristics of Colombia and its significant diversity require a substantial study and analysis of user needs and possible solutions which involve technological adaptation and innovative solutions. Implementation: The current power system and the market legislation should be changed gradually. Initially, microgrids could be installed in ZNIs and isolated areas. Thus, the implementation of new technologies should offer energy security and especially storage systems which can reduce the dependence of great hydro power plants, which are generally affected during the dry season.

7. Conclusions This paper describes the most important cases of microgrids in two contexts, research works developed in laboratories and microgrids used as an alternative way of energy generation in difficult-to-access areas. Having analyzed the Colombian case in the introductory part, the paper has also discussed the generation composition and the installed capacity of the country for the year 2013, as well as the infrastructure stock with special emphasis to areas of difficult access or with no electricity in the country. Furthermore, it has presented solutions incorporating renewable resources, which has been implemented by the government through the IPSE. Hydropower is the largest electricity generation source of SIN in Colombia. However, a significant reduction of 18% is shown on projected power reserve margins for 2022. In order to solve this, the government proposes to incorporate FNCE in its expansion plans. Additionally, this would be a viable option for the generation in ZNI. The successful development of microgrids in Colombia depends on the regulations and the confluence of state and private investment. The (SIN) must be adapted to new technologies, especially in automation and communication, as well as the standards for their construction and maintenance. Microgrids deployment should be achieved gradually, for which it is necessary to work in three areas: Training, Research and Implementation. In addition, it is essential to formulate a program for the development of renewable energy sources, which may allow the diversification of the national energy market by having more supply options for the future, as well as anticipating the depleting of fossil fuels reserves. By adopting an energy policy which promotes renewable energy as established by the Law 1715 issued in 2014, Colombia may therefore strengthen the image of a

“green” country. Nevertheless, this law should be regulated as well in terms of incentives for renewable energy production and the sale of surplus power to the grid.

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