Increasing the Penetration of Renewable Energy Sources in Isolated Islands Through the Connection of Their Power Systems
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Increasing the Penetration of Renewable Energy Sources in Isolated Islands through the Connection of their Power Systems. The Case of Pico and Faial Islands, Azores Márcia Filipa Oliveira Alves [email protected] Instituto Superior Técnico, Universidade de Lisboa, Portugal October 2017 Abstract Anxiety over escalating environmental degradation on the part of governments, non-governmental organizations, companies and populations has reached fever proportions in recent years. In practice, the awareness of this concern has been reflected in a reduction of the consumption of fossil fuels and in an increasing use of renewable energy sources (RES). The implementation of RES in isolated power systems, as is the case of islands, constitutes both a challenge and an opportunity. The RES intermittency originates problems of grid stability, as well as a mismatch between power demand and supply. The connection between isolated power systems can decrease the RES variability and, thereby, to minimize the problems associated with their intermittency. In this work, the endogenous resources of the islands of Pico and Faial were characterized and their power systems were modeled. A scenario considering the connection between the power systems of the two islands is proposed with the objective of increasing the RES penetration in these islands. The proposed scenario comprises a combination of biomass, municipal solid waste, wind, solar, wave and hydro as RES. It is still proposed the use of sodium-sulphur batteries as storage technology of electricity, and fossil fuels to cover the mismatch between demand and supply. The results obtained show that rehabilitating the renewable technologies already installed in the two islands and constructing a biomass power plant and a municipal solid waste valorization plant, the RES penetration in the Islands increases by about 27 pp as compared to the Business as Usual scenario. As a result, the fossil fuels consumption and the corresponding CO2 emissions are reduced by about 25%. The implementation of this scenario represents additional annual costs for both islands of less than 3.5 million euros. In addition, based on the knowledge gained from the present study, measures that may lead, in the long run, to the complete elimination of the use of fossil fuels in all sectors of activity of both islands are presented and discussed. Keywords: Isolated Power Systems; Renewable Energy Sources Intermittency; Renewable Energy Sources Integration; Energy in Islands 1 Introduction Small islands exhibit a high energy dependence on imported fossil fuels, relying on external countries to ensure their normal daily life. This condition not only restricts their ability to be self-reliable but also compromises their economy owing to the very high fuels’ cost in islands [1]. By using the island’s endogenous resources, the renewable energy technologies may be able to tackle these issues. Nevertheless, Renewable Energy Sources (RES) integration in an isolated power system presents limitations. High renewable energy penetration levels create difficulties both in terms of grid stability and mismatch between demand and supply. These issues are associated with the intermittent nature of most of the renewable resources. Therefore, each power system must be carefully designed to obtain an energy mix as broad as possible as well as a reliable backup [1]. The Autonomous Region of the Azores (ARA) is a part of the EU Outermost Regions (OR). The OR are characterized by small land areas, isolation and significant distances to the European continent. The islands have isolated power systems and a dependence on fossil fuels for energy supply. This provides both a challenge and an opportunity for RES integration. ARA is an autonomous territory of the Portuguese Republic and it is constituted by nine islands, divided into three territorial groups: oriental group, central group and occidental group. All nine islands of the archipelago have their own isolated power system, and electricity is provided by the same company, Electricidade Dos Açores (EDA). In 2016, the total electricity demand amounted to 800.77 GWh [2]. The archipelago is considerably dependent on imported fossil fuels, exhibiting an overall RES penetration share of 33% on its electricity production [2]. The RES penetration, however, is rather heterogeneous, with some islands presenting RES penetration shares above 50%, and others of 0 as far as electricity is concern. Most of the archipelago’s renewable energy production is currently originated from the geothermal resource, which was responsible for 19% of the total generated power in 2016 [2]. The wind power generation is the second biggest contributor with a share of 9.1% [2]. Pico and Faial are part of the central group of the archipelago and are rather close to each other, with only 7.5 km separating them. The islands exhibit very similar characteristics. Each island has around 6% of the archipelago’s population. The islands’ main economic activities both focus on the primary sector, and exhibit very little representation of the industry sector. The islands present similar energy needs, with a power consumption of approximately 40 GWh in 2016 [2]. The sectors showing the highest power consumption correspond to the commerce and services sectors and the residential sector. Regarding power production, both islands are very dependent on imported fossil fuels and significant endogenous resources which only a very small part of them are being exploited as a source of energy; indeed, the RES penetration in both islands is only 13% with most of the RES share originated from wind power [2]. The present study is focused on the maximization of the RES penetration in Pico and Faial Islands, Azores, by the year 2030. The main objective is the study is to develop and propose a credible scenario to allow for such maximization, while taking into consideration the economic feasibility of its implementation. The present work concentrates solely on two of the nine islands that constitute the ARA. In particular, the scenario proposed considers the establishment of a novel, common, power system 1 for both islands, which will allow them to share both the power demand and power supply. To accomplish this objective, a complete characterization of Pico’s and Faial’s power systems is made, both in terms of demand and supply. Moreover, the islands’ endogenous energy resources are mapped and their potential is calculated. The baseline scenario is modeled in a well- known energy planning tool, EnergyPLAN. A credible scenario is developed for increasing the penetration of RES in both islands through an undersea connection of their power systems – the proposed scenario includes wind, hydro, solar and biomass and urban waste as RES for the power supply, and an energy storage system; and quantification of the costs associated to the implementation of the proposed scenario. Finally, a presentation and discussion of measures that may lead, in the long run, to the complete elimination of the use of fossil fuels in all sectors of activity of both islands is carried out. 2 Literature review The ARA has been extensively studied in recent years when it comes to renewable energy. A number of studies have been undertaken on the increase of the RES penetration in islands and the feasibility of 100% RES energy systems. Martins et al [3] examined the possibility of increasing the renewable energy penetration in Terceira Island, in Azores, in order to reduce its fossil fuels extreme dependence. The authors conclude that the potential of RES in Terceira can supply almost all the island’s energy needs. Nonetheless, the authors pointed out that it is not possible to completely eliminate fossil fuel usage and achieve total energy independence [3]. Parissis et al [4] evaluated the integration of wind energy for electricity production, and hydrogen production as the energy storage system in Corvo Island, in Azores. They concluded that with the proposed system it is possible to cover 80% of the island’s electricity needs, with a 43% reduction in the power generation cost [4]. Duić et al [5] applied the RenewIslands methodology to the Corvo Island and concluded that a synergy exists for the merging of the electricity and water supply systems. Results showed that the RES penetration can be increased from 25% up to 70% share, without and with energy storage, respectively, without significant additional costs [5]. Cross-Call [1] studied the integration of energy storage in scenarios for increasing the wind energy penetration in S. Miguel, Faial and Flores Islands, in Azores. Results indicated that renewable energy systems coupled with energy storage may produce significant savings in operating costs. The study showed that storage power assumes a higher relevance to achieve cheaper and cleaner energy goals, when compared to storage capacity. Furthermore, the author concluded that islands relying exclusively on wind for power generation, such as Faial Island, will not be able to attain aggressive clean energy goals even with storage integration [1]. The Younicos Company has recently installed a 4 MW battery energy storage system, which allowed for wind and solar energy to unsure the base-load generation in Graciosa Island, in Azores. This allows for up to 100% instantaneous renewable power penetration and a 65% RES penetration share on a yearly basis [6]. The implemented project will reduce the overall energy costs on the island [7]. Bağcı [8] concluded that it was possible to transform Peng Chau Island, in Hong Kong, in a ‘Zero Energy Island’ by producing all of the island’s required electrical energy with the available endogenous resources. The results showed that a combination of two of the RES with the most potential is sufficient to meet the island’s energy demand [8]. Godina et al [9] analyzed the results of the implementation of the first MW-level energy project of a system with wind as the power source and water storage in El Hierro Island, in the Canarias archipelago.