Assessment of Renewable Sources for the Energy Consumption in Malta in the Mediterranean Sea
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energies Article Assessment of Renewable Sources for the Energy Consumption in Malta in the Mediterranean Sea Vincenzo Franzitta *, Domenico Curto, Daniele Milone and Davide Rao Department of Energy, Information Engineering and Mathematical Models, University of Palermo (UNIPA), 90128 Palermo, Italy; [email protected] (D.C.); [email protected] (D.M.); [email protected] (D.R.) * Correspondence: [email protected]; Tel.: +39-091-238-61941 Academic Editor: Francesco Asdrubali Received: 24 September 2016; Accepted: 28 November 2016; Published: 8 December 2016 Abstract: The main purpose of this paper is to analyze the energy production in the Maltese islands, focusing on the employment of renewable energies in order to increase their energy independence. The main renewable source here proposed is wave energy: thanks to a strategic position, Malta will be able to produce electrical energy using an innovative type of Wave Energy Converter (WEC) based on the prototype of a linear generator realized by University of Palermo. The use of this new technology will be able to cut down the electrical energy production from traditional power plants and, consequently, the greenhouse gas emissions (GHG). Wave energy source and off-shore photovoltaic (PV) technology are here proposed. Particularly, the installation of 12 wave farms, for a total installed capacity of 86 MW, will generate about 9.5% of Malta’s energy requirement in 2025, while the installation of 9.6 MW of off-shore PV will generate about 0.73%. Keywords: wave energy; renewable energy; Mediterranean Sea; Wave Energy Converter (WEC); point absorber; Malta 1. Introduction The electrical power production is almost completely based on diesel generators in many islands in the Mediterranean Sea [1]. The fuel is usually shipped by mainland and long underwater cables sometimes connect the small islands to the mainland [2]. Due to these reasons, in small islands, the electrical power production shows higher operating costs and losses than in mainland [3]. The use of Renewable Energy Sources (RES), such as solar, wind, biomass and sea wave, will produce a reduction in energy dependence on fossil fuels and the improvement of the efficiency of the electrical grid [4]. The RES also contribute to the reduction of greenhouse gas (GHG) emissions and environmental pollution. After the ratification of the Kyoto Protocol, the European Community undertook measures to cut its GHG emissions by 8% of 1990 levels [5]. According to the European Directive 2009/28/EC (Annex I), Malta is required to produce 10% of its energy from RES in gross final consumption by 2020 [6,7]. Malta’s target is considerable, although it is lower than other European Countries, because Malta presents quite particular conditions, such as other Mediterranean islands: high population density, limited available land and an ever increasing electricity demand. In order to achieve the environmental and energetic targets [8], Malta will have to use all available renewable sources [9]. Moreover, Malta’s electrical grid needs several developments in order to minimize the electrical problems caused by varying power outputs of RES, such as wind, solar and sea wave [10]. The following Figure1 shows the properties of the future grid. Every available RES will be used to produce electrical energy [11]. In order to match the electrical load and the electrical production by RES, new innovative storage systems have to be developed. Energies 2016, 9, 1034; doi:10.3390/en9121034 www.mdpi.com/journal/energies Energies 2016, 9, 1034 2 of 17 Energies 2016, 9, 1034 2 of 17 Figure 1. Electrical grid with main RES and storage systems.systems. Among various RES, in the last years the wave energy source, thanks to its great potential, has Among various RES, in the last years the wave energy source, thanks to its great potential, has sparked great interest, evidenced by several prototypes and researches [12]. This work analyses the sparked great interest, evidenced by several prototypes and researches [12]. This work analyses the wave energy source along Malta’s coasts, which can be exploited to produce electrical energy using wave energy source along Malta’s coasts, which can be exploited to produce electrical energy using an an innovative Point Absorber, which directly converts the mechanical energy of sea wave into innovative Point Absorber, which directly converts the mechanical energy of sea wave into electrical electrical output, minimizing the energetic conversion losses [13]. This system is based on a new output, minimizing the energetic conversion losses [13]. This system is based on a new linear generator linear generator prototype realized by Department of Energy of University of Palermo (Italy). prototype realized by Department of Energy of University of Palermo (Italy). In particular, Section 2 of this paper reports some geographical and climate data about Malta’s In particular, Section2 of this paper reports some geographical and climate data about Malta’s archipelago. Section 3 analyzes the electrical energy demand in Malta during the last years. Section 4 archipelago. Section3 analyzes the electrical energy demand in Malta during the last years. Section4 describes the sea wave energy potential along Maltese coasts. Section 5 describes an energy converter, describes the sea wave energy potential along Maltese coasts. Section5 describes an energy converter, designed and developed by Palermo University, able to exploit wave and solar sources at the same designed and developed by Palermo University, able to exploit wave and solar sources at the same time. Finally, Section 6 proposes an energetic scenario based on the energy converter of Palermo time. Finally, Section6 proposes an energetic scenario based on the energy converter of Palermo University, evaluating the annual electrical production and the avoided CO2 emissions. University, evaluating the annual electrical production and the avoided CO2 emissions. 2. Maltese Archipelago Malta’s CountryCountry is an archipelago, locatedlocated inin thethe middlemiddle ofof thethe MediterraneanMediterranean Sea.Sea. It is situated at 80 km south of Sicily, 284 km east of Tunisia and 333 km north of Libya. The capital city is is Valletta, Valletta, withwith thethe geographicalgeographical coordinatescoordinates 35◦°53’53’ N–14N–14°35’◦35’ E. It is situated in the largestlargest islandisland (called(called alsoalso Malta) ofof thethe archipelago,archipelago, asas shownshown inin FigureFigure2 2.. 2 Malta covers an an overall overall area area of of 316 316 km km, 2so, soit is it one is one of the of thesmallest smallest European European Countries. Countries. The 2 TheMaltese Maltese Archipelago Archipelago is characterized is characterized by by a ahigh high population population density density (1318 (1318 in./km2, ,2012). 2012). The The main islandisland (Malta) (Malta) has has a apopulation population of ofabout about 368,250 368,250 inhabitants inhabitants (2012), (2012), while while the total the population total population is about is about416,515 416,515 inhabitants inhabitants (2012). (2012). The Maltese The Maltese Archipelago Archipelago is composed is composed by several by several islands, islands, but butonly only the 2 2 2 thebiggest biggest three three of them of them are populated: are populated: Malta MaltaIsland Island(245.8 km (245.8), Gozo km2 ),(67.1 Gozo km (67.1) and km Comino2) and (2.8 Comino km ), (2.8as shown km2), asin shown Figure in 2. Figure The 2archipelago. The archipelago includes includes also 18 also uninhabited 18 uninhabited smal smallerler islands. islands. There There are arenumerous numerous bays bays along along the theindent indenteded coastline coastline of the of theislands. islands. Malta’s islands are mainly rocky, withwith terracedterraced fields,fields, drydry vegetation,vegetation, rockrock andand limestone.limestone. InIn the Maltese Archipelago, permanent rivers or lakes areare absent; during autumn and winter, rainsrains formform torrents.torrents. TheThe annual rainfall in Malta is low, aboutabout 578578 mmmm perper year. In order toto overcome thethe limitedlimited availability of water in thethe inhabitedinhabited islandsislands ofof Malta,Malta, sixsix desalinationdesalination plants are installed,installed, two of whichwhich areare alwaysalways on.on. Energies 2016, 9, 1034 3 of 17 Energies 2016, 9, 1034 3 of 17 Figure 2. View of the Maltese Archipelago. Figure 2. View of the Maltese Archipelago. Due to its latitude and the central location in the Mediterranean Sea, Malta has a Subtropical DueMediterranean to its latitude climate and with the very central mild winters location and in warm the Mediterraneansummers. The average Sea, Maltayearly hastemperature a Subtropical is Mediterraneanaround 23 °C climate during withthe day very and mild 16 °C winters in the night. and January warm is summers. the coldest The month average of the year, yearly while temperature August is aroundis the 23 hottest.◦C during The average the day annual and 16temperature◦C in the of night. the sea January is 20 °C, ranging is the coldest from 15 monthto 16 °C ofin February the year, to while August26 °C is thein August. hottest. Winters The average in Malta annualare usually temperature mild, but during of the the sea wint iser 20 months◦C, ranging it tends fromto get 15windy to 16 ◦C from wind blowing from the north-east and with a main maximum speed about 80 km/h [14]. Concerning in February to 26 ◦C in August. Winters in Malta are usually mild, but during the winter months it the solar radiation, in Malta there are about 3000 sunlight hours per year, with a minimum daily average tendsof to 5.2 get h in windy December from to winda maximum blowing daily from average the of north-east 12 h in July and [15]. with a main maximum speed about 80 km/h [14]. Concerning the solar radiation, in Malta there are about 3000 sunlight hours per year, with a3. minimumElectrical Energy daily averageProduction of 5.2in Malta h in December to a maximum daily average of 12 h in July [15]. 3.