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Improving energy efficiency in the transportation sector could significantly contribute to limiting environmental degradation and decelerate the depletion of existing fossil-fuel reserves. Effective methods for increasing energy efficiency include the adoption of eco-driving – especially in urban areas – the utilization of more efficient vehicles, and the shift to green public transportation. In any case, to develop a sustainable and efficient transportation strategy in selected cases (e.g., smart cities), the use of so-called clean new technology vehicles should be adopted. The Laboratory of Soft Energy Applications and Environmental Protection (SEALAB) of the Piraeus University of Applied Sciences (formerly TEI of Piraeus) has recently undertaken, within the framework of its innovative activities, the development, construction, and operation of the country’s first stand-alone solar electric vehicle charging station (EVCS), CARPORT, monitoring all energy data and thereby supporting and strengthening the country’s efforts in infrastructure development in the field of electromobility. More specifically, this innovative effort, described in this chapter, aims to accelerate the implementation of a European national electrification action plan through the construction of EVCSs based on photovoltaic generators. The proposed solar EVCS is considered to be one of the most environmentally friendly solutions, capable of supporting the decarbonization of the European transport sector.
J. K. Kaldellis; G. Spyropoulos; St. Liaros. Supporting Electromobility in Smart Cities Using Solar Electric Vehicle Charging Stations. Mediterranean Green Buildings & Renewable Energy 2016, 501 -513.
AMA StyleJ. K. Kaldellis, G. Spyropoulos, St. Liaros. Supporting Electromobility in Smart Cities Using Solar Electric Vehicle Charging Stations. Mediterranean Green Buildings & Renewable Energy. 2016; ():501-513.
Chicago/Turabian StyleJ. K. Kaldellis; G. Spyropoulos; St. Liaros. 2016. "Supporting Electromobility in Smart Cities Using Solar Electric Vehicle Charging Stations." Mediterranean Green Buildings & Renewable Energy , no. : 501-513.
In recent decades, renewable energy applications have gained significant market share in the global electricity generation sector and in covering the electricity needs of non-interconnected islands. Among the emerging renewable energy technologies, wave energy utilization is indisputably ranked among the energy sources that could resolve the controversial issue of energy demand coverage. Greece, located in the eastern Mediterranean region (with a special focus on the Aegean archipelago), has almost 16,000 km of coastline, so the exploitation of marine technologies could contribute to the power supply of most islands as well as of the mainland. In this study, an extensive evaluation of the expected wave power in the Aegean Sea is carried out, focusing on selected sea sites where wave buoys have been located. The basic wave parameters (e.g., significant wave height) along with the corresponding wave power are analyzed for selected regions. Taking into consideration the vast energy potential available in the sea as well as the fact that coastal areas can benefit greatly from the implementation of such energy solutions, the current study emphasizes both the northern and southern parts of the Aegean archipelago where many grid islands not connected to the mainland are dependent on conventional fuels and, more precisely, oil supplies to meet their urgent electricity needs. Based on the results of this survey, the future prospects of wave energy and the possible implementation of innovative marine technologies could be supported, providing the remote island communities of the Aegean Sea with clean electrical energy at a reasonable cost.
F. Xanthaki; Chr. Giannaraki; E. F. Zafeiraki; J. K. Kaldellis. Exploitation of Wave Energy Potential in Aegean Sea: Greece. Mediterranean Green Buildings & Renewable Energy 2016, 515 -529.
AMA StyleF. Xanthaki, Chr. Giannaraki, E. F. Zafeiraki, J. K. Kaldellis. Exploitation of Wave Energy Potential in Aegean Sea: Greece. Mediterranean Green Buildings & Renewable Energy. 2016; ():515-529.
Chicago/Turabian StyleF. Xanthaki; Chr. Giannaraki; E. F. Zafeiraki; J. K. Kaldellis. 2016. "Exploitation of Wave Energy Potential in Aegean Sea: Greece." Mediterranean Green Buildings & Renewable Energy , no. : 515-529.
Energy and fuel supply chains (SCs) and their optimisation not only in techno-economic terms but also accounting for environmental and social implications imbedded in each supply chain option render a very interesting research topic, especially in areas with limited energy resources and areas where strict air quality limitations apply. Considering that the aim of this chapter is to present a developed methodology and the assorted modelling tool for the optimisation of alternative SCs considering sustainability dimensions in the design and operation on top of technical limitations. To evidence that a small-scale power planning problem will be assessed, that is, an isolated consumer, Milos island in Greece, for a specific timeframe, proofing the implementation possibilities and flexibility of the model to change over different optimisation targets and limitations applicable in each specific energy decision strategy.
Christiana Papapostolou; Emilia M. Kondili; John K. Kaldellis. Development of an Optimisation Model for the Evaluation of Alternative Energy and Fuel Supply Chains. Renewable Energy in the Service of Mankind Vol II 2015, 325 -334.
AMA StyleChristiana Papapostolou, Emilia M. Kondili, John K. Kaldellis. Development of an Optimisation Model for the Evaluation of Alternative Energy and Fuel Supply Chains. Renewable Energy in the Service of Mankind Vol II. 2015; ():325-334.
Chicago/Turabian StyleChristiana Papapostolou; Emilia M. Kondili; John K. Kaldellis. 2015. "Development of an Optimisation Model for the Evaluation of Alternative Energy and Fuel Supply Chains." Renewable Energy in the Service of Mankind Vol II , no. : 325-334.
According to the Amsterdam Treaty, declaration No. 30, “…insular regions suffer from structural handicaps linked to their island status, the permanence of which impairs their economic and social development”. Considering the above, the present work aims to present different aspects of the current energy and water situation in Mediterranean Sea islands, using as case studies two representative French and Greek island regions. To this end, common problems as well as differences that call upon the elaboration of more case-specific solutions are identified. Accordingly, emphasis is given on future prospects for renewable energy sources and the role of integrated, hybrid solutions including energy storage and desalination aspects.
D. Zafirakis; Gilles Notton; Chr. Darras; M. L. Nivet; E. Kondili; J. K. Kaldellis. The Role of Renewable Energy Sources in Solving Energy and Water Problems of Mediterranean Sea Islands. Renewable Energy in the Service of Mankind Vol II 2015, 195 -203.
AMA StyleD. Zafirakis, Gilles Notton, Chr. Darras, M. L. Nivet, E. Kondili, J. K. Kaldellis. The Role of Renewable Energy Sources in Solving Energy and Water Problems of Mediterranean Sea Islands. Renewable Energy in the Service of Mankind Vol II. 2015; ():195-203.
Chicago/Turabian StyleD. Zafirakis; Gilles Notton; Chr. Darras; M. L. Nivet; E. Kondili; J. K. Kaldellis. 2015. "The Role of Renewable Energy Sources in Solving Energy and Water Problems of Mediterranean Sea Islands." Renewable Energy in the Service of Mankind Vol II , no. : 195-203.
As renewable energy projects have gradually been introduced in various forms and in many places around the world, public skepticism on these developments has emerged and siting decisions have, in several cases, been determined by intense conflicts and debate. In this context, the present study focuses on the assessment of the levels of public acceptability for existing and new renewable energy projects, namely wind farms, small hydro and photovoltaics (PVs), in a representative region of Southern Greece. A point of particular interest in this survey is the adverse environmental conditions and poor air quality existing in the area under investigation, resulting from the long-term operation of a lignite-based thermal power station. A postal, three-part survey has been conducted based on a representative sample of local inhabitants. According to the results obtained, high levels of acceptability for existing and new projects have been encountered for all technologies examined. Interestingly, better results concerned PV applications, with the positive trend towards new projects being illustrated by the high percentage of about 85%. Similarly, wind and hydro energy applications demonstrate high acceptability of the order of 80%. Furthermore, local habitants' experience on already operating renewable energy projects in the region has also designated their “tolerance” on the main environmental impacts of these technologies (visual, noise, land occupation etc.). However, this survey also reveals a specific minority of people that are opposed to renewable energy applications, either disregarding any environmental, social and financial benefits or just weighing benefits less heavily than the reasons of opposition.
J.K. Kaldellis; M. Kapsali; El. Kaldelli; Ev. Katsanou. Comparing recent views of public attitude on wind energy, photovoltaic and small hydro applications. Renewable Energy 2013, 52, 197 -208.
AMA StyleJ.K. Kaldellis, M. Kapsali, El. Kaldelli, Ev. Katsanou. Comparing recent views of public attitude on wind energy, photovoltaic and small hydro applications. Renewable Energy. 2013; 52 ():197-208.
Chicago/Turabian StyleJ.K. Kaldellis; M. Kapsali; El. Kaldelli; Ev. Katsanou. 2013. "Comparing recent views of public attitude on wind energy, photovoltaic and small hydro applications." Renewable Energy 52, no. : 197-208.
The photovoltaic (PV) technology has made considerable progress during the recent years in both grid connected and stand-alone applications, especially in areas of high local solar potential. In this context, the interest recently demonstrated in the Greek region concerning PVs encourages the investigation of optimum operation conditions for such systems. At the same time, summer-only applications, being rather common in Greece, require maximum exploitation of the local solar potential during the specific period of the year. For this purpose, an experimental study is currently carried out in the area of Athens, in order to evaluate the performance of different PV panel tilt angles during the summer period. According to the experimental results obtained, the angle of 15° (±2.5°) is designated as optimum for almost the entire summer period, while conclusions drawn are accordingly theoretically validated by means of established solar geometry equations.
John Kaldellis; Dimitrios Zafirakis. Experimental investigation of the optimum photovoltaic panels’ tilt angle during the summer period. Energy 2011, 38, 305 -314.
AMA StyleJohn Kaldellis, Dimitrios Zafirakis. Experimental investigation of the optimum photovoltaic panels’ tilt angle during the summer period. Energy. 2011; 38 (1):305-314.
Chicago/Turabian StyleJohn Kaldellis; Dimitrios Zafirakis. 2011. "Experimental investigation of the optimum photovoltaic panels’ tilt angle during the summer period." Energy 38, no. 1: 305-314.
One of the least analyzed side effects of atmospheric air pollution is the degradation of PV-panels’ performance due to the deposition of solid particles varying in composition, size and type. In the current study, the experimental data concerning the effect of three representative air pollutants (i.e. red soil, limestone and carbonaceous fly-ash particles) on the energy performance of PV installations are analyzed. According to the results obtained, a considerable reduction of PVs’ energy performance is recorded, depending strongly on particles’ composition and source. Subsequently, a theoretical model has been developed in order to be used as an analytical tool for obtaining reliable results concerning the expected effect of regional air pollution on PVs’ performance. Furthermore, experimental results concerning the dust effect on PVs’ energy yield in an aggravated – from air pollution – urban environment are used to validate the proposed theoretical model.
J.K. Kaldellis; M. Kapsali. Simulating the dust effect on the energy performance of photovoltaic generators based on experimental measurements. Energy 2011, 36, 5154 -5161.
AMA StyleJ.K. Kaldellis, M. Kapsali. Simulating the dust effect on the energy performance of photovoltaic generators based on experimental measurements. Energy. 2011; 36 (8):5154-5161.
Chicago/Turabian StyleJ.K. Kaldellis; M. Kapsali. 2011. "Simulating the dust effect on the energy performance of photovoltaic generators based on experimental measurements." Energy 36, no. 8: 5154-5161.
Although wind energy exploitation dates back five thousand years ago, contemporary societies are based almost exclusively on fossil fuels for covering their electrical energy needs. On the other hand, during the last thirty years, security of energy supply and environmental issues have reheated the interest for wind energy applications. In this context, the present work traces the long and difficult steps of wind energy development from the California era to the construction of huge offshore wind parks worldwide, highlighting the prospects and the main challenges of wind energy applications towards the target of 1000 GW of wind power by 2030.
John K. Kaldellis; D. Zafirakis. The wind energy (r)evolution: A short review of a long history. Renewable Energy 2011, 36, 1887 -1901.
AMA StyleJohn K. Kaldellis, D. Zafirakis. The wind energy (r)evolution: A short review of a long history. Renewable Energy. 2011; 36 (7):1887-1901.
Chicago/Turabian StyleJohn K. Kaldellis; D. Zafirakis. 2011. "The wind energy (r)evolution: A short review of a long history." Renewable Energy 36, no. 7: 1887-1901.
Photovoltaic (PV) applications, gaining worldwide interest during the last years, comprise a promising renewable energy based solution, able to considerably contribute to the constantly increasing energy demand of our planet. Currently, residential applications possess a considerable share of the global PV market since fiscal and practical incentives have reinforced their promotion. On the other hand, high population concentration, rapid industrialisation and economic development of urban areas all over the world have caused significant degradation of the urban air quality. In this context, the actual performance of five identical pairs of roof-top PV-panels, operating in the aggravated urban environment of Athens (from the atmospheric air pollution point of view), is currently evaluated. For this purpose, a series of systematic experimental measurements is conducted within a certain time period and the influence of different dust deposition densities on the energy yield and the economic performance of the small power station is estimated. According to the results obtained, the presence of dust considerably affects the PV-panels’ performance since even a relatively small dust deposition density (≈1 g/m2) may result in remarkable energy losses corresponding almost to 40 €/kWp on an annual basis.
J.K. Kaldellis; A. Kokala. Quantifying the decrease of the photovoltaic panels’ energy yield due to phenomena of natural air pollution disposal. Energy 2010, 35, 4862 -4869.
AMA StyleJ.K. Kaldellis, A. Kokala. Quantifying the decrease of the photovoltaic panels’ energy yield due to phenomena of natural air pollution disposal. Energy. 2010; 35 (12):4862-4869.
Chicago/Turabian StyleJ.K. Kaldellis; A. Kokala. 2010. "Quantifying the decrease of the photovoltaic panels’ energy yield due to phenomena of natural air pollution disposal." Energy 35, no. 12: 4862-4869.
Pumped hydro storage (PHS) systems which are located at isolated regions and are able to exploit the rejected wind energy amounts produced by local wind farms, seem to gain interest worldwide and to become essential in regard to higher shares of renewable-generated electricity. Despite the high wind potential encountered in many Greek island regions, the wind energy contribution to the electrification of these areas is significantly restricted due to imposed electrical grid limitations. In this context, the current work examines the economic viability of a wind-based PHS system (wind-hydro solution) which provides the local electrical grid of an Aegean Sea island, Lesbos, with guaranteed energy amounts during the peak load demand periods. Based on the maximization of the project’s net present value, the optimum system configuration is proposed while many other feasible solutions are revealed. According to the results obtained the implementation of this project demonstrates excellent technical and economic performance, while at the same time renewable energy sources (RES) contribution is doubled reaching almost 20% of the Lesbos island electrical energy consumption.
M. Kapsali; J.K. Kaldellis. Combining hydro and variable wind power generation by means of pumped-storage under economically viable terms. Applied Energy 2010, 87, 3475 -3485.
AMA StyleM. Kapsali, J.K. Kaldellis. Combining hydro and variable wind power generation by means of pumped-storage under economically viable terms. Applied Energy. 2010; 87 (11):3475-3485.
Chicago/Turabian StyleM. Kapsali; J.K. Kaldellis. 2010. "Combining hydro and variable wind power generation by means of pumped-storage under economically viable terms." Applied Energy 87, no. 11: 3475-3485.
The vast growth of the mobile telecommunication (T/C) sector during the recent years has led to the extension of the respective networks even to the most remote areas. Many of these areas, however, often lack electricity grid supply and as a result installation of energy autonomous T/C stations, usually based on diesel-oil electricity generation, is essential. On the other hand, technological developments and considerable procurement cost reduction of photovoltaics (PVs) encourage also the use of PV stand-alone configurations, as an alternative energy solution for the operation of these remote T/C stations. Instead of using PV-battery configurations alone, contribution of a diesel engine in terms of moderate fuel consumption may downsize the system and improve its economic performance. In this context, an optimum sizing methodology currently developed is used to determine the dimensions of such an autonomous hybrid system, based on the criterion of minimum initial cost. The developed methodology is accordingly applied to a representative Greek area of high solar potential under different scenarios of fuel consumption and panels’ tilt angle. From the results obtained, the proposed hybrid power station appears to be one of the most attractive energy solutions for the support of remote T/C stations, providing increased levels of reliability and presenting low maintenance needs.
J.K. Kaldellis. Optimum hybrid photovoltaic-based solution for remote telecommunication stations. Renewable Energy 2010, 35, 2307 -2315.
AMA StyleJ.K. Kaldellis. Optimum hybrid photovoltaic-based solution for remote telecommunication stations. Renewable Energy. 2010; 35 (10):2307-2315.
Chicago/Turabian StyleJ.K. Kaldellis. 2010. "Optimum hybrid photovoltaic-based solution for remote telecommunication stations." Renewable Energy 35, no. 10: 2307-2315.
The exploitation of solar energy by autonomous, photovoltaic (PV) based systems offers the opportunity for satisfying the electrification needs of numerous remote consumers worldwide in an environmentally friendly way. On the other hand, the sustainable character of these systems is strongly questioned by the energy intensity of processes involved in the various life cycle (LC) stages of the system components. Although there are several studies concerned with the estimation of the energy pay-back period (EPBP) for grid-connected systems, the same is not valid for stand-alone configurations. In this context, an integrated methodology is currently developed in order to estimate the EPBP of PV-battery (PV-Bat) configurations ensuring 100% energy autonomy. The main scope of the proposed analysis is to determine the optimum size of a corresponding system, comprised of multi-crystalline (mc-Si) PV modules and lead-acid (PbA) batteries, based on the criterion of minimum embodied energy, i.e. minimum EPBP. For this purpose, a representative case study examined considers the electrification needs of a typical remote consumer on the Island of Rhodes, Greece. According to the results obtained, the autonomous energy character of the system is reflected by the comparatively higher EPBP in comparison with the corresponding grid-connected option, nevertheless the PV-Bat configurations analyzed clearly constitute sustainable energy solutions. Finally, in order to increase the reliability of the calculation results, a sensitivity analysis is carried out, based on the variation of the input energy content data.
J.K. Kaldellis; D. Zafirakis; E. Kondili. Energy pay-back period analysis of stand-alone photovoltaic systems. Renewable Energy 2010, 35, 1444 -1454.
AMA StyleJ.K. Kaldellis, D. Zafirakis, E. Kondili. Energy pay-back period analysis of stand-alone photovoltaic systems. Renewable Energy. 2010; 35 (7):1444-1454.
Chicago/Turabian StyleJ.K. Kaldellis; D. Zafirakis; E. Kondili. 2010. "Energy pay-back period analysis of stand-alone photovoltaic systems." Renewable Energy 35, no. 7: 1444-1454.
The entirety of Aegean Sea Islands, including Crete, is characterized during the last decade by a considerable annual increase of the electrical power demand exceeding the 5% in annual basis. This continuous amplifying electricity consumption is hardly fulfilled by several outmoded internal combustion engines usually at a very high operational cost. On the other hand most of the islands possess high wind potential that may substantially contribute in order to meet the corresponding load demand. However, in this case some wind energy absorption problems related with the collaboration between wind parks and the local electricity production system cannot be neglected. In this context, the present study is devoted to realistically estimating the maximum wind energy absorption in autonomous electrical island networks. For this purpose a new reliable and integrated numerical algorithm is developed, using the available information of the corresponding electricity generation system, in order to calculate the maximum acceptable wind power contribution in the system, under the normal restrictions that the system manager imposes. The proposed algorithm is successfully compared with existing historical data as well as with the results of a recent investigation based almost exclusively on the existing wind parks energy production.
J.K. Kaldellis; Kosmas Kavadias; A.E. Filios. A new computational algorithm for the calculation of maximum wind energy penetration in autonomous electrical generation systems. Applied Energy 2009, 86, 1011 -1023.
AMA StyleJ.K. Kaldellis, Kosmas Kavadias, A.E. Filios. A new computational algorithm for the calculation of maximum wind energy penetration in autonomous electrical generation systems. Applied Energy. 2009; 86 (7-8):1011-1023.
Chicago/Turabian StyleJ.K. Kaldellis; Kosmas Kavadias; A.E. Filios. 2009. "A new computational algorithm for the calculation of maximum wind energy penetration in autonomous electrical generation systems." Applied Energy 86, no. 7-8: 1011-1023.
The progress met in the world market of photovoltaics underlines the maturity of investments realized, guarantees the reliability of the technology utilized and designates the variety of applications in covering the energy demands of both stand-alone and grid connected consumers. Concerning stand-alone systems, the incorporation of photovoltaic systems in water pumping applications is thought to be one of the most popular and ideal uses of solar energy exploitation, especially under the common allegation of coincidence between insolation and water demand. In this study, an attempt to investigate the opportunities of a PV powered water pumping system able to meet additional – apart from the water pump – electricity loads, results in the development of an optimum sizing methodology which is accordingly validated by experimental measurements. From the results obtained, it becomes clear that a properly designed PV-pumping configuration of 610 Wp is capable of covering both the electricity (max 2 kWh/day) and the water (max 400 L/h) management demands of a large variety of remote consumers.
J.K. Kaldellis; G.C. Spyropoulos; K.A. Kavadias; I.P. Koronaki. Experimental validation of autonomous PV-based water pumping system optimum sizing. Renewable Energy 2009, 34, 1106 -1113.
AMA StyleJ.K. Kaldellis, G.C. Spyropoulos, K.A. Kavadias, I.P. Koronaki. Experimental validation of autonomous PV-based water pumping system optimum sizing. Renewable Energy. 2009; 34 (4):1106-1113.
Chicago/Turabian StyleJ.K. Kaldellis; G.C. Spyropoulos; K.A. Kavadias; I.P. Koronaki. 2009. "Experimental validation of autonomous PV-based water pumping system optimum sizing." Renewable Energy 34, no. 4: 1106-1113.
The oil-dependent electricity generation situation met in the Aegean Archipelago Islands is in great deal determined by increased rates of fuel consumption and analogous electricity production costs, this being also the case for other island autonomous electrical networks worldwide. Meanwhile, the contribution of renewable energy sources (RES) to the constant increase recorded in both the Aegean islands’ annual electricity generation and the corresponding peak load demand is very limited. To compensate the unfavorable situation encountered, the implementation of energy storage systems (ESS) that can both utilize the excess/rejected energy produced from RES plants and improve the operation of existing thermal power units is recommended. In the present study, a techno-economic comparison of various RES-ESS configurations supported by the supplementary or back-up use of existing thermal units is undertaken. From the results obtained, the shift of direction from the existing oil-dependent status to a RES-based alternative in collaboration with certain storage technologies entails – apart from the clear environmental benefits – financial advantages as well.
J.K. Kaldellis; D. Zafirakis; Kosmas Kavadias. Techno-economic comparison of energy storage systems for island autonomous electrical networks. Renewable and Sustainable Energy Reviews 2009, 13, 378 -392.
AMA StyleJ.K. Kaldellis, D. Zafirakis, Kosmas Kavadias. Techno-economic comparison of energy storage systems for island autonomous electrical networks. Renewable and Sustainable Energy Reviews. 2009; 13 (2):378-392.
Chicago/Turabian StyleJ.K. Kaldellis; D. Zafirakis; Kosmas Kavadias. 2009. "Techno-economic comparison of energy storage systems for island autonomous electrical networks." Renewable and Sustainable Energy Reviews 13, no. 2: 378-392.
One of the main factors affecting public acceptance of wind parks is their visual impact. Very often this problem can be solved by taking into account certain methods and techniques. This paper reviews the most common methods (such as Quechee analysis, the Spanish method, the method of visual limits); as example is presented the evaluation of the visual impact of a wind park in Chania, Crete. Besides, the outcomes are combined with the psychometric testing of the residents by the use of questionnaires and with the values of the Spanish method. The results of the study prove that the quantification of the potential visual impact could minimize this, apparently, main reason that affects public acceptance.
Theocharis Tsoutsos; Androniki Tsouchlaraki; Manolis Tsiropoulos; John Kaldellis. Visual Impact Evaluation Methods of Wind Parks: Application for a Greek Island. Wind Engineering 2009, 33, 83 -91.
AMA StyleTheocharis Tsoutsos, Androniki Tsouchlaraki, Manolis Tsiropoulos, John Kaldellis. Visual Impact Evaluation Methods of Wind Parks: Application for a Greek Island. Wind Engineering. 2009; 33 (1):83-91.
Chicago/Turabian StyleTheocharis Tsoutsos; Androniki Tsouchlaraki; Manolis Tsiropoulos; John Kaldellis. 2009. "Visual Impact Evaluation Methods of Wind Parks: Application for a Greek Island." Wind Engineering 33, no. 1: 83-91.
According to long-term wind speed measurements the Aegean Archipelago possesses excellent wind potential, hence properly designed wind energy applications can substantially contribute to fulfill the energy requirements of the island societies. On top of this, in most islands the electricity production cost is extremely high, while significant insufficient power supply problems are often encountered, especially during the summer. Unfortunately, the stochastic behaviour of the wind and the important fluctuations of daily and seasonal electricity load pose a strict penetration limit for the contribution of wind energy in the corresponding load demand. The application of this limit is necessary in order to avoid hazardous electricity grid fluctuations and to protect the existing thermal power units from operating near or below their technical minima. In this context, the main target of the proposed study is to present an integrated methodology able to estimate the maximum wind energy penetration in autonomous electrical grids on the basis of the available wind potential existing in the Aegean Archipelago area. For this purpose a large number of representative wind potential types have been investigated and interesting conclusions have been derived.
J.K. Kaldellis. The wind potential impact on the maximum wind energy penetration in autonomous electrical grids. Renewable Energy 2008, 33, 1665 -1677.
AMA StyleJ.K. Kaldellis. The wind potential impact on the maximum wind energy penetration in autonomous electrical grids. Renewable Energy. 2008; 33 (7):1665-1677.
Chicago/Turabian StyleJ.K. Kaldellis. 2008. "The wind potential impact on the maximum wind energy penetration in autonomous electrical grids." Renewable Energy 33, no. 7: 1665-1677.
Hydropower is a proven technology for electricity generation, contributing with almost 20% to the fulfilment of the planet electricity demand. Hydropower is also renewable because it draws its essential energy from the sun and particularly from the hydrological cycle. Greece and more precisely the west and north part of the mainland possesses significant hydropower potential that is up to now partially exploited. In the present survey, one investigates the existing situation concerning the applications of hydropower plants in Greece, while the results obtained are compared with the corresponding international and European situation. Subsequently, emphasis is laid on estimating the electricity-generation utilization degree of the existing large hydropower stations, using 25-year long official data. The results obtained underline the fact that the electricity generation is not a priority for the national water management policy and most Greek hydropower stations are used mainly to meet the corresponding peak load demand. On the other hand, increased interest to create numerous new small hydropower plants throughout Greece has been expressed during the last 5 years. According to the information gathered and analyzed, one may state that the available local hydropower potential is quite promising and can substantially contribute to the accomplishment of the national-EU target to cover the 21% of the corresponding electricity consumption from renewable resources. For this purpose one should first define an approved and rational water resources management plan and secondly support the increased utilization of large and small hydropower plants for electricity generation. In this case, properly designed hydropower plants should lead to considerable profits, contributing also in the country's independency from imported oil and accomplishing the Kyoto protocol obligations.
J.K. Kaldellis. Critical evaluation of the hydropower applications in Greece. Renewable and Sustainable Energy Reviews 2008, 12, 218 -234.
AMA StyleJ.K. Kaldellis. Critical evaluation of the hydropower applications in Greece. Renewable and Sustainable Energy Reviews. 2008; 12 (1):218-234.
Chicago/Turabian StyleJ.K. Kaldellis. 2008. "Critical evaluation of the hydropower applications in Greece." Renewable and Sustainable Energy Reviews 12, no. 1: 218-234.
The high wind and solar potential along with the extremely high electricity production cost met in the majority of Greek Aegean islands comprising autonomous electrical networks, imply the urgency for new renewable energy sources (RES) investments. To by-pass the electrical grid stability constraints arising from an extensive RES utilization, the adaptation of an appropriate energy storage system (ESS) is essential. In the present analysis, the cost effect of introducing selected storage technologies in a large variety of autonomous electrical grids so as to ensure higher levels of RES penetration, in particular wind and solar, is examined in detail. A systematic parametrical analysis concerning the effect of the ESSs’ main parameters on the economic behavior of the entire installation is also included. According to the results obtained, a properly sized RES-based electricity generation station in collaboration with the appropriate energy storage equipment is a promising solution for the energy demand problems of numerous autonomous electrical networks existing worldwide, at the same time suggesting a clean energy generation alternative and contributing to the diminution of the important environmental problems resulting from the operation of thermal power stations.
J.K. Kaldellis; D. Zafirakis. Optimum energy storage techniques for the improvement of renewable energy sources-based electricity generation economic efficiency. Energy 2007, 32, 2295 -2305.
AMA StyleJ.K. Kaldellis, D. Zafirakis. Optimum energy storage techniques for the improvement of renewable energy sources-based electricity generation economic efficiency. Energy. 2007; 32 (12):2295-2305.
Chicago/Turabian StyleJ.K. Kaldellis; D. Zafirakis. 2007. "Optimum energy storage techniques for the improvement of renewable energy sources-based electricity generation economic efficiency." Energy 32, no. 12: 2295-2305.
Hydropower is the most widely used renewable energy source worldwide, contributing almost with 18.5% to the fulfillment of the planet electricity generation. However, most locations in Europe appropriate for the installation of large hydro power stations have already been exploited. Furthermore, there is a significant local communities’ opposition towards new large power stations; hence, small hydro power stations remain one of the most attractive opportunities for further utilization of the available hydro potential. Greece and more precisely the country's mainland possesses a significant hydro-power potential which is up to now only partially exploited. In parallel, a large number of private investors have officially expressed their interest in creating small hydro power stations throughout the country, encouraged by the significant Greek State subsidy opportunities for renewable energy applications. However, up to now a relatively small number of projects have been realized, mainly due to decision-making problems, like the administrative bureaucracy, the absence of a rational national water resources management plan and the over-sizing of the proposed installations. Certainly, if the above problems are suitably treated, small hydro-power plants can be proved considerably profitable investments, contributing also remarkably to the national electricity balance and replacing heavy polluting lignite and imported oil. In the context of the above interesting issues, the present study reviews in detail the existing situation of small hydropower plants in Greece and investigates their future prospects as far as the energy, economic and environmental contribution are concerned.
J.K. Kaldellis. The contribution of small hydro power stations to the electricity generation in Greece: Technical and economic considerations. Energy Policy 2007, 35, 2187 -2196.
AMA StyleJ.K. Kaldellis. The contribution of small hydro power stations to the electricity generation in Greece: Technical and economic considerations. Energy Policy. 2007; 35 (4):2187-2196.
Chicago/Turabian StyleJ.K. Kaldellis. 2007. "The contribution of small hydro power stations to the electricity generation in Greece: Technical and economic considerations." Energy Policy 35, no. 4: 2187-2196.