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Stochastic power generation is the new reality in power system management. Voltage Control mechanisms based on physical assets of the power system are deemed inadequate and are not guaranteed to lead the energy transformation in a way that ensures system security as well as cost-effective operation. Many countries that recently attained deregulated Balancing Market environments are in need of regulatory provisions and rigorous extension of electricity market mechanisms. On 1 November 2020, the Greek Electricity Market commenced operations conforming to the European Target Model. Apart from the innate difficulties a transformation such as this contains, more challenges occur as Greece is bound by European law to design market-based incentive mechanisms to remunerate Ancillary Services provided to the power system. This paper aims to examine some of the technical and regulatory aspects linked with—future—Transmission System Operator (TSO) and Distribution System Operator (DSO) cooperation in overcoming local transmission system problems concerning Voltage regulation. The interaction between localized Voltage Control Market (VCM) and the Balancing Market, the incorporation and competition of Distributed Energy Resources (DER) and Transmission Energy Resources (TER) within the VCM along with the TSO - DSO procedures and products standardization are the focus points of the present research paper. [ABSTRACT FROM AUTHOR]

Coffee consumption is a daily habit for the majority of people worldwide, resulting in consistently large amounts of residue. Spent coffee ground (SCG) is the residue obtained during the brewing process. It represents an abundant source of energy biomass, or raw material for added value products but it is still largely unexploited. This residue may find several applications, such as in polymers/composites precursors, solid/liquid biofuels, biofertilizers, and so forth. The aim of the present paper was the pilot production of pellets by mixing SCG and other residual biomass feedstock. Coffee residues were mixed at different ratios (0, 10, 30, 50, 70, 90 wt%) together with: (i) forestry residues; (ii) sawmill residues; (iii) urban prunings; (iv) maize residues; (v) peach prunings; and (vi) miscanthus. Samples of each fuel mixture were analyzed at the Solid Fuels Laboratory of CPERI/CERTH (Chemical Process and Energy Resources Institute/Centre for Research and Technology Hellas) in Greece by applying established standards. The results of the analyses show that the mixing of biomass residues with coffee could result in competitive solid biofuels. More specifically, pellets with up to 10% coffee residues, mixed with sawmill residues, complied with the class A2 limits set by the international standard ISO 17225‐2 for wood pellets, and pellets with up to 30% coffee residues complied with the class B limits for wood pellets for commercial/residential applications. Urban prunings mixed with 10 wt% coffee residues are within the limits set for class B wood pellets. [ABSTRACT FROM AUTHOR]

In recent times, the power sector has become a focal point of extensive scientific interest, driven by a convergence of factors, such as mounting global concerns surrounding climate change, the persistent increase in electricity prices within the wholesale energy market, and the surge in investments catalyzed by technological advancements across diverse sectors. These evolving challenges have necessitated the emergence of new imperatives aimed at effectively managing energy resources, ensuring grid stability, bolstering reliability, and making informed decisions. One area that has garnered particular attention is the accurate prediction of end-user electricity load, which has emerged as a critical facet in the pursuit of efficient energy management. To tackle this challenge, machine and deep learning models have emerged as popular and promising approaches, owing to their having remarkable effectiveness in handling complex time series data. In this paper, the development of an algorithmic model that leverages an automated process to provide highly accurate predictions of electricity load, specifically tailored for the island of Thira in Greece, is introduced. Through the implementation of an automated application, an array of deep learning forecasting models were meticulously crafted, encompassing the Multilayer Perceptron, Long Short-Term Memory (LSTM), One Dimensional Convolutional Neural Network (CNN-1D), hybrid CNN–LSTM, Temporal Convolutional Network (TCN), and an innovative hybrid model called the Convolutional LSTM Encoder–Decoder. Through evaluation of prediction accuracy, satisfactory performance across all the models considered was observed, with the proposed hybrid model showcasing the highest level of accuracy. These findings underscore the profound significance of employing deep learning techniques for precise forecasting of electricity demand, thereby offering valuable insights with which to tackle the multifaceted challenges encountered within the power sector. By adopting advanced forecasting methodologies, the electricity sector moves towards greater efficiency, resilience and sustainability. [ABSTRACT FROM AUTHOR]

Reducing the carbon emissions from hotels on non-interconnected islands (NII) is essential in the context of a low carbon future for the Mediterranean region. Maritime tourism is the major source of income for Greece and many other countries in the region, as well as hot-temperate and tropical regions worldwide. Like many NIIs, Rhodes attracts a high influx of tourists every summer, doubling the island's energy demand and, given the high proportion of fossil fuels in the Rhodian energy supply, increasing carbon emissions. Using the theoretical framework 'FINE', this paper presents the optimisation of a medium-sized hotel's energy system with the aim of reducing both cost and carbon emissions. By introducing a Photovoltaic (PV) net metering system, it was found that the carbon emissions associated with an NII hotel's energy system could be reduced by 31% at an optimised cost. It is suggested that large-scale deployment of PV or alternative renewable energy sources (RES) in NII hotels could significantly reduce carbon emissions associated with the accommodation sector in Greece and help mitigate climate change. [ABSTRACT FROM AUTHOR]

Food waste is one of the biggest global challenges. Thinking and acting for closed-loop cycles for energy and resources recovery is pivotal for meeting the Sustainable Development Goal 12.3 (SDG 12.3) by 2030. In this paper, the multifaceted problem of food waste and Greece's national policy of circular economy is briefly given. Greece produces the highest annual per capita food waste output (142 kg) in Europe, indicating that the problem is rather large for the country. The solution to the problem inextricably linked to the implementation of the food waste hierarchy, was investigated through a survey integrating the possibility of energy recovery. The tailored questionnaire sent via e-mails and social media with the goal of identifying a snapshot of Greek citizens' conceptions and practices regarding the management of their household food waste, and their familiarity with circular economy concepts. Results have shown that most respondents are aware of the problem's existence, however, without considering it as important, according to 1565 responses gathered and analyzed using the IBM SPSS Statistics 27.0 program. Greek individuals are eager to recycle their food waste without expecting anything in return, but the majority seek recommendations on how to do it. [ABSTRACT FROM AUTHOR]

The idea of the past gestures at an individual or collective's knowledge of events which occurred before the present. Given this spacious conceptual fitting, the past can appear to be a vaguely theorized knowledge space. But, what makes the past? Is it existent only to be manipulated by culture? Or is it a resource which can be located? This essay seeks to explore what the past is in a world rendered in a new materialist spirit. New materialisms challenge scholars to discard the divide between socially construction and materiality. Through the concept of "resource materialities," a genealogy will be constructed which links Science Technology Studies, the subfield STS of the Underground, and media theory together. Based on experience participant observing an archeological dig in Arkadia, Greece, this essay will then proceed to take seriously that the past is not a limitless symbolic resource by investigating two underground resources from which the past can be derived: ancient ceramic fragments and lignite coal deposits. The resulting account of the making of ceramic fragments as a knowledge resource and lignite as an energy resource intends to provide a description of the choreography required to produce these resources. Ultimately, this account provides evidence in support of the concept of "resource materialities." In the critical space following, this paper will discuss problems with the relationality of resources and recommend action. Lastly, this essay concludes by exploring the consequences of this conceptualization of past making. [ABSTRACT FROM AUTHOR]

Purpose - The aim of this paper is to discuss the impact of energy pricing on the implementation of low energy design principles in buildings. Design/methodology/approach - The problem of rising air-conditioning loads is not simply a matter of availability of power-plants, but also one of the limited time periods over which demand peaks occur. The relationship between the feasibility of technical solutions and pricing policies of electricity is examined by means of a Greek case study, which is representative for Southern Europe. Findings - The paper finds that in conventional air-conditioning systems the impact of the peak cooling demand on the building's capital expenditure is low, compared to the operational expenses over the buildings' life cycle. In that sense the latter's reduction lies in the interest of the building's user, rather than the investor, if, however, changes in the pricing policies were to be adopted, annual operational expenses would more than double, making energy saving measures far more attractive. Such a scenario would reflect the Californian experience of 2000. However, it is misleading to think only of covering the demand, which is a product of the building's characteristics. Passive cooling techniques are very efficient in reducing the building's cooling load. The challenge lies in the integration of such techniques and solar cooling technologies, resulting thus in feasible solutions. Practical implications - The evaluation of energy conservation techniques should be considered under the criterion of embodying the actual marginal operational cost of a utility to its rates, when providing peak loads. Originality/value - The paper rejects the false dilemma of passive vs active energy conservation approaches, and demonstrates that on the long run the ‘business as usual’ way of keeping electricity rates fairly flat is not only impracticable, but also destructive for energy conservation as such. [ABSTRACT FROM AUTHOR]

Climate change is expected to significantly affect countries in Southern Europe and the Mediterranean Basin, causing higher-than-average temperature increases, considerable reductions in rainfall and water runoff, and extreme events such as heatwaves. These pose severe threats to local energy systems, requiring a reliable and quantitative risk analysis. A methodological approach is thus proposed which covers both energy supply and demand, utilizing the latest climate projections under different greenhouse gas emissions scenarios and an appropriate scale for each energy form. For energy supply technologies, risks are assessed through statistical regression models and/or mathematical equations correlating climatic parameters with energy productivity. To analyze climate risks for energy demand, bottom–up models were developed, integrating both behavioral and policy aspects which are often considered in a very limited way. The results show that climate change will mainly affect electricity generation from hydroelectric and thermal power plants, with variations depending on the plants' locations and uncertainties associated with precipitation and runoff changes. The climate risks for solar and wind energy were found to be low. Energy consumption will also be affected, but the range of risks depends on the ambition and the effectiveness of measures for upgrading the thermal performance of buildings and the intensity of climate change. [ABSTRACT FROM AUTHOR]

The ongoing economic recession that hit Greece in 2009 has considerably influenced the use of domestic heating sources, as households struggle to reduce energy consumption and the respective costs. With global energy demand and the heating oil prices being rather volatile, but not in extremis during the last five years, alternative heating systems with the respective resources are being considered by consumers, in order to cut down heating expenses. At the same time, these alternatives are not always the greener or the most sustainable ones. The current paper presents and analyses the impacts of the recession on the consumers’ behaviour regarding space heating. A field survey was carried out, by means of interviews with questionnaires, in Northern Greece, an area where there is an increased energy demand for heating and hence an intensive need for efficient solutions. The questionnaire was structured in an appropriate way in order to collect the available data, not only to identify the significant variables but also to capture any minor details that could be helpful in achieving our goal: gain reliable information about the energy consumption and the respective cost of heating at an annual base as well as their interconnection. The variables employed in the survey include among others: the building type, construction year, surface, main heating system, alternative heating systems (fireplace, AC unit, electric heater and stove), operating hours, saving measures, energy consumption and annual income. Any potential correlation between the aforementioned parameters will be explored while a mathematical description of their relation will be further attempted. The results of the survey carried out during 2011 and 2012 are presented and the most noteworthy conclusions are highlighted. The initial outcome proves that there is a certain trend of shrinkage of the households’ budget spent for domestic heating purposes as a consequence of the inhabitants’ income reduction and the dramatic tax increase on energy. [ABSTRACT FROM AUTHOR]

PHPS is a mature energy storage technology, leading to more efficient energy management and further integration of Renewable Energy Sources (RES). This paper investigates the implementation of such a system at Kastraki, Greece, combined with a second upstream reservoir with a total capacity of 10 hm3 and evaluates its efficiency. The position and the geometric characteristics of the second reservoir are determined with ArcGIS. When excess of energy exists, water is pumped from Kastraki reservoir and stored in the upper one. Otherwise, the stored water is used for energy production. The simulation is performed for 40 years with a monthly time step. Furthermore, another simulation for a typical day in July is conducted, when water and energy needs are increased. The system is evaluated in terms of covering the water supply and energy needs, as well as in terms of efficient energy management. Several results can be obtained, as follows: i) the reliability of the PHPS system for the coverage of monthly water supply and irrigation needs is 82.84 %. ii) The coverage of water supply needs for a typical day in July is 99.99 %. iii) The average monthly coverage of energy needs amounts to 83.86 %. [ABSTRACT FROM AUTHOR]

When hearing about solar energy, most people think about heating their buildings, but only a few are aware of its cooling capacity. Depending of the available amount of radiation, a solar system can stand alone, or have an additional energy source to cover the peak loads. But for times when neither heating, nor cooling are needed, the solar energy may be stored for different periods (from several hours to half a year). After showing the initial status and most recent developments of solar heating and cooling systems, together with possibilities of energy storage for large systems, this paper presents both theoretical and practical approach of a prototype system developed in Greece, by CRES, within HIGH COMBI European project. [ABSTRACT FROM AUTHOR]

Amidst a global discourse on energy resources, it is imperative to provide decision makers with a comprehensive overview of energy consumption (EC) associated with various projects, particularly wastewater treatment plants (WWTPs). Ensuring compliance with stringent effluent quality criteria in the treatment of municipal wastewater necessitates a substantial EC, representing a predominant factor contributing to the operational expenses incurred by WWTP. Machine learning (ML) techniques can contribute to the estimation of the WWTPs' EC, which requires efficient and accurate data. This article uses data from several municipal WWTP projects in Greece, which are examined in order to produce EC estimation models. Data were first statistically analyzed, according to the context of project attributes and the context of EC, and correlation analysis identified the appropriate predictive project variables. Then, the attribute selection function in Waikato Environment for Knowledge Analysis 3.8.4 (WEKA 3.8.4) software emphasized the most effective subset of variables. The extracted variables from the combination of the correlation analysis and the WEKA attribute function were used as input neurons for the construction of neural network (NN) models, in the Fast Artificial Neural Network Tool 1.2 (FANN Tool 1.2). The optimum NN model resulted in a mean squared error (MSE) of 8.99899 × 10−5 and was based on treatment capacity, flow rate, influent load, and served population as its inputs. Notably, the research highlights the potential generalizability of these models in Greece and beyond the Greek context, offering valuable tools for stakeholders to inform decision making, allocate resources efficiently, and improve energy-efficient designs, resulting in cost savings and sustainability benefits. [ABSTRACT FROM AUTHOR]

A detailed review of wave energy resource assessment and the state-of-the-art of deployed wave energy converters (WECs) in real environmental conditions in the Mediterranean Sea have been analysed in this study. The installed power of the several deployed WECs in the Mediterranean Sea varies between 3–2500 kW. Ten project cases of deployed WECs in the basin are presented, with their analysis of the essential features. Five different types of WEC have already been tested under real environmental conditions in Italy, Greece, Israel and Gibraltar, with Italy being the Mediterranean country with the most deployed WECs. The main questions of the relevant studies were the ongoing trends, the examination of WECs in combination with other renewable sources, the utilising of WECs for desalination, and the prospects of wave energy in the Mediterranean islands and ports. This paper is the first comprehensive study that overviews the recent significant developments in the wave energy sector in the Mediterranean countries. The research concludes that the advances of the wave energy sector in the Mediterranean Sea are significant. However, in order to commercialise WECs and wave energy exploitation to become profitable, more development is necessary. [ABSTRACT FROM AUTHOR]

This paper presents the results of a thorough planning investigation carried out by the Transmission System Operator (TSO) and the Distribution Network Operator (DNO) in Greece in order to study the interconnections of the Aegean Islands with the mainland power system. The feasibility of interconnecting islands is based on the need for a reliable power supply to isolated and autonomous islands, reducing the operating costs of the power generation system through the withdrawal of high-cost oil-fired generating units, and the further ability to increase renewable energy source (RES) penetration in the country's energy mix, according to directions imposed by the National Energy and Climate Plan. Among the alternative topologies and interconnection technologies considered, the final selection of the interconnection scheme selected for inclusion in the development plans of TSO and DNO was based on their detailed comparative evaluation, considering financial and other technical criteria. [ABSTRACT FROM AUTHOR]

The disadvantages of fossil fuels and their impact on the environment have made the transition to renewable energy sources essential to cover our energy needs. However, different energy resources have a different impact on energy poverty conditions in the world, an issue that is important to examine and properly address. This study examines the impact that fossil fuels final energy consumption in households per capita and renewables and biofuels final energy consumption in households per capita have on energy poverty conditions in Europe, using panel data from 28 European countries for the time period 2004–2019 and static and dynamic regression models, while also performing various econometric tests. The findings indicate that GDP per capita and fossil fuels are linked to an inverse relationship to energy poverty conditions. Renewables and biofuels are also linked to an inverse relationship to the inability to keep homes adequately warm and the presence of leaks, damp, or rot in the dwelling, but they could be considered a driver of arrears on utility bills. In addition, a comparative analysis between Sweden, Germany, and Greece and their conditions on energy poverty and energy transition was conducted, highlighting the differences existing between the three European countries. The findings of the research can be useful for governments and policy makers to develop strategies that promote energy transition while protecting energy consumers. [ABSTRACT FROM AUTHOR]

Need for food and energy challenge humanity. Producing biofuels from energy crops leads to the dilemma: “energy crops for biofuel or for food?” This paper aims to answer this dilemma through the SWOT analysis, for the first time for Greece. Results of the first alternative show strengths including creation of direct and indirect jobs (Biofuel production industry), diversity of energy supply, and positive contribution of the greenhouse effect. Weaknesses include environmental impact, and dependence on land availability (additional need of arable land other than that required to grow food). Energy and climate change priority on policy agenda, EU directives promoting the use of biofuels, and economic competitiveness with fossil fuels, could create the external environment to promote bioenergy production. Conversely, results of the second option show strengths including food security, and non-risk of deforestation in order to find new land. Weaknesses include failure to increase employment opportunities by not creation of indirect jobs, and non exploitation of marginal lands. Respective external environmental factors include solution to food crisis, use of second generation biofuels, and development of new and non-edible varieties. Dependence on fossil fuels and failure to comply with the world agenda regarding climate change, constitute threats for this option. [ABSTRACT FROM AUTHOR]

This article examines current energy-related disputes in the Eastern Mediterranean. It does so by situating them in the context of the Middle East's broader geopolitical landscape and by showing how global powers' interests and involvement have become contingent on the international and regional political environments. The latter augmented the intensity of the contestation and helped move identifiable and tangible factors, such as Exclusive Economic Zones, into the imaginative realms of geopolitics. They also provided the concerned actors with opportunities to balance out their adversaries and, by implication, diminished their willingness to compromise. Although the global powers' interest in Eastern Mediterranean energy resources is limited, the European Union does have interests in these reserves and related aspects. The fact that the monetisation of these resources is highly dependent on the EU market provides the EU with an immense amount of "buyer power" to stabilise the region and potentially balance the fears of both Greece and Turkey. [ABSTRACT FROM AUTHOR]

The continuous process of marketization of employment relations in a variety of European countries has raised questions about the power of collective social actors and their legitimizing role in policy-making. The article examines the responses of employers' associations to institutional changes towards marketization in the context of the Greek economic crisis. The analysis exposes the hidden fractures between and within the peak-level employers' associations and unveils a variation in their strategic responses towards institutional changes. To explain this variation, the article advances a power-based explanation and argues that the institutional changes altered the associations' interest representation and power resources, which, in turn, redefined their role and identities in the employment relations system. [ABSTRACT FROM AUTHOR]

Abstract: In the present paper a Linear Programming (LP) methodology for the city of Athens, Attica region is implemented trying to identify the energy supply levels based on the energy use, aiming to determine the optimal way for the energy needs to be covered. The final aim was to find the best solution/s to meet the (metropolitan) city''s energy needs using Renewable Energy Sources (RES) and additionally implement a techno-economic analysis through a developed tool, in order to find which RES should participate in the city''s energy system examining different scenarios focusing not only on the projects'' economical success but also on minimizing the cost for the society. [Copyright &y& Elsevier]

Abstract: This paper is founded on a statistical wind data analysis for two interconnected wind farms in Greece. Specifically, after the acquisition of a representative set of climatology data by two meteorological masts installed in two different mountainous regions, an annual power output prediction is carried out in order to estimate the performance and viability of the selected wind turbines in the parks. Two alternative power output simulation models are used; one empirical and one computational, the results of which are examined in a comparative manner. Furthermore, a wake losses’ estimation is performed via the application of two different wake models, while a simple noise emission impact analysis is implemented. The study ends with a brief financial assessment of the two wind energy projects. The main outcome of the energy calculations is that the empirical numerical tool underestimates the total annual energy production of the two wind farms as well as their capacity factors. The wake models’ comparative overview indicates a low percentage of wake losses for both the wind parks, which ensures the maximum power yield achievement. Finally, the results of the noise emission analysis prove that the turbines’ predicted noise signals fall within the limits of recent regulation protocols. [Copyright &y& Elsevier]

Abstract: In the recent years, the debate on the necessity of pumped storage systems in the Greek power supply system has started. In the current decade, the Greek power system will gradually try higher RES penetration, mainly due to wind energy and photovoltaics integration. Variability of wind and PV generation and the current structure of the Greek power system introduce technical constraints, which should be taken into consideration in the forthcoming large scale RES integration. This paper examines the ability of the Greek power system to absorb renewable power and the necessity of pumped storage systems. The feasibility of pumped storage systems is discussed in three different scenarios of wind–photovoltaics integration. Results show that for the gradual increase of variable output RES, pumped storage systems are required, but the feasibility of pumped storage systems is not proved in the intermediate scenarios of RES integration. [Copyright &y& Elsevier]

Abstract: This paper deals with the causal relationship analysis between Gross Domestic Product, Energy Intensity and CO2 emissions in Greece from 1977 to 2007, by means of Johansen cointegration tests and Granger-causality tests based on a multivariate Vector Error Correction Modeling. Results indicate that there is a set of uni-directional and bi-directional causalities among the selected time series. We performed a model Variance Decomposition Analysis using Choleski technique and we provided a comparison with other studies. The findings of the study have significant policy implications for countries like Greece as the decoupling of CO2 emissions and economic growth seems quite unlikely. [Copyright &y& Elsevier]

Abstract: The most important constraint toward the successful implementation of the energy efficiency investments in Greece remains the absence of appropriate and competitive financial schemes. Energy efficiency improvements seems to be one of the areas that JESSICA instrument should focus on in the case of Greece, considering that energy efficiency constitutes a major component of sustainable urban development. The scope of this paper is to present, in an updating way, an analysis of energy efficiency investments’ environment in Greece as well as to examine the potential role of the JESSICA instruments, aiming to the supporting of the real implementation of energy efficiency investments in Greece. In addition, a rigid methodological note is presented for the analysis as well as evaluation of the JESSICA instruments for energy efficiency projects in Greece. [ABSTRACT FROM AUTHOR]

Abstract: Photovoltaic (PV) power systems are becoming one of the most developing investment areas in the field of Renewable Energy Sources (RES). A statement of the status quo of PV power systems in Greece, and their contribution towards the improvement of power system reliability, is the scope of the present paper. Siting and installation of PV power systems is performed according to a recent Greek law, along with environmental and geographical constraints. Meteorological data are computed, formulated and imported to appropriate software in order to simulate the PV units and generate their power output. Data for unserved loads, resulting from load shedding during peak hours, are compared to the above estimated power production. Assuming that a proportion of the eventually unsupplied power could be provided by the accessed power generation of the PV units, the reliability of both transmission and distribution system is improved. The impact on the transmission system is shown by an improvement of LOLP and LOEP indices, whereas peak shaving for the Interconnected Greek Transmission System (IGTS) is also illustrated. For the distribution system the impact is quantified using the distribution system reliability indices SAIDI, SAIFI, and CAIDI. Finally, the resulting improvement is also expressed in financial terms. [Copyright &y& Elsevier]

Abstract: Energy consumption in buildings vary significantly, depending on factors as the use of the building, the construction type, maintenance, existing heating, cooling and lighting systems and other types of services. Hotel buildings have high energy consumption rate, as a result of their unique operational characteristics. Energy consumption in hotels is among the highest in the non-residential building sector in absolute values. Available specific information on the energy characteristics, thermal performance, energy losses, electric loads, and comfort conditions play significant role for the sustainable development of hotel''s systems. These data can also be used to identify whether there is space for improvement in new or existing hotels by comparing them against predicted or actual building energy performance. The aim of the present paper is to analyze the energy and exergy utilization in four hotels in Rethimno, Crete (Southern Greece) and in Kassandra, Halkidiki (Northern Greece). [Copyright &y& Elsevier]

Abstract: The favorable climate conditions of the island of Crete and the recent legislation for utilization of renewable energy sources provide a substantial incentive for installation of photovoltaic power plants. In this paper, the grid connected photovoltaic park of C. Rokas SA in Sitia, Crete, is presented, and its performance is evaluated. The photovoltaic park has a peak power of 171.36kWp and has been in operation since 2002. The park is suitably monitored during 1 year, and the performance ratio and the various power losses (temperature, soiling, internal, network, power electronics, grid availability and interconnection) are calculated. The PV park supplied 229MWh to the grid during 2007, ranging from 335.48 to 869.68kWh. The final yield (Y F) ranged from 1.96 to 5.07h/d, and the performance ratio (PR) ranged from 58 to 73%, giving an annual PR of 67.36%. [Copyright &y& Elsevier]

Abstract: Most medium and small islands of the Aegean Archipelagos face serious infrastructure problems, strongly related with the limited electrical energy available at extremely high cost. On the other hand, the area is characterized by very high wind speeds and abundant solar energy, thus the exploitation of the available renewable energy sources (RES) may significantly contribute to the fulfillment of the local societies energy demand at minimum environmental and macroeconomic cost. However, the stochastic availability of wind energy and the variable availability of solar energy, the daily and seasonal electricity demand fluctuations, as well as the limited local electrical network capacity result in serious restrictions concerning the maximum renewable power penetration. In this context, the present paper investigates the possibility of creating a combined electricity generation facility based on the exploitation of wind or/and solar potential of an area as well as on the utilization of an appropriate energy storage configuration in order to replace the existing thermal power stations with rational investment requirements. For this purpose, the major parameters of the proposed integrated configuration are firstly calculated and its financial viability is accordingly analyzed. One of the main targets of the proposed solution is to maximize the RES exploitation of the area at a minimum electricity generation cost, while special emphasis is given in order to select the most cost-efficient energy storage device available. According to the results obtained the proposed solution is not only financially attractive but also improves the quality of the electricity offered to the local communities, substituting the expensive and heavily polluting existing thermal power stations. [Copyright &y& Elsevier]

Abstract: This paper examines four mutually exclusive scenarios for the expansion of the Greek electricity system developed by official authorities and representing alternative views on meeting electricity demand. The aim is to encompass all positive and negative side-effects characterizing the electricity generation technologies assumed to participate in each scenario and emphasis is given to the particular role of renewable energy sources which represent a major differentiating factor between them. The calculation of economic, technical and environmental performances of the examined scenarios for the year 2010 shows that electricity planning is a complicated task since improvements in one policy target are accompanied by losses in others. In order to resolve this conflict, the scenarios are comparatively evaluated with two decision support techniques, multicriteria decision analysis and cost–benefit analysis, which are capable of broadening the strict boundaries of a financial analysis while avoiding intuitive solutions that are often applied in practice. Following the two completely different evaluation approaches, it is confirmed that the scenario assuming the highest penetration of renewable energy sources is the best compromise configuration for the Greek power generation sector. [Copyright &y& Elsevier]

Lignite has long dominated Greece's electricity system, boosting economic growth and energy security, given the abundant domestic resources. In line with its national and international commitments to climate action and sustainable development, the country is currently facing the urgent need to transform its energy system, overcome its technological lock-ins, and transition to a low-carbon economy. Drawing from the need to secure a sustainable transition that considers the impacts of a lignite phase-out on local economies, this study builds upon the Multi-Level Perspective framework and further focuses on the phase-out of the dominant fossil fuel, rather than solely exploring the phase-in of new technologies. By delving into the landscape that established lignite as the mainstream energy resource in Greece, as well as the factors sustaining its dominance despite niche technologies and innovations challenging the regime, we discuss how the envisaged decarbonization can be socially just and effective across multiple sustainability dimensions. [ABSTRACT FROM AUTHOR]

This editorial is prepared for the Applied Energy Journal as a Virtual Special Issue (VSI) and it overviews the research work presented at the NAXOS 2018 6th International Conference on Sustainable Solid Waste Management, held from 13th to 16th June 2018 in Naxos Island, Greece. The research articles presented in VSI highlight the recent developments in waste valorisation for the recovery of energy, fuels and value-added products. They also cover the primary hurdles and potential solutions moving towards more sustainable society. This editorial not only presents the overall summary of the extended research papers from NAXOS 2018, but also provides an overview of the current trends and developments in the fields of waste management, waste valorization, and energy production systems. The articles published in this VSI cover a wide range of topics, including energy recovery from waste, waste to energy technologies, sustainable energy systems, anaerobic digestion, thermal arc plasma gasification, microalgal-based biorefinery, waste management, modelling of advanced gasification systems, waste valorization, and microbial fuel cell technology. 10 manuscripts, out of total 21 extended mansucripts invited, were accepted for publication in the Applied Energy Journal through peer review process conducted by the expert reviewers in the relevant fields with the aid of the guest editors. [ABSTRACT FROM AUTHOR]

The energy discoveries in the Eastern Mediterranean since the 2000s have placed the long-standing rivalry between Turkey and Cyprus (and by extension Greece) in a new context, bringing also Egypt and Israel into the geopolitical equation. Turkey, on the one hand, has adopted an assertive profile, whereas, on the other hand, two axes of cooperation have been formed, Greece-Cyprus-Egypt and Greece-Cyprus-Israel, convening trilateral summits and signing agreements. In view of that, it is currently upheld that the confluence of energy interests among the actors of the trilateral summits has facilitated a legalisation throughout the Eastern Mediterranean, propelling states towards the development of the energy resources according to the UNCLOS, and the implementation of the international law in the Cyprus problem, as a necessary means of guaranteeing the actors' sovereignty, creating norms, and enhancing security, without targeting any third country. The argument shows how legalisation, as a special form of institutionalisation, and soft law, in particular, nurture regional cooperation and place it under the "protective wings" of international institutions. [ABSTRACT FROM AUTHOR]

• "A Hierarchical Distributed Predictive Control Approach for Microgrids Energy Management". • Optimization of flexible buildings in smart microgrids. • An innovative distributed consensus-based MPC architecture with coordination. • Several experiments in a distributed energy laboratory facility. • Feasibility of realtime optimization proved. This paper addresses the problem of management and coordination of energy resources in a typical microgrid, including smart buildings as flexible loads, energy storages and renewables. The overall goal is to provide a comprehensive and innovative framework to maximize the overall benefit, still accounting for possible requests to change the load profile coming from the grid and leaving every single building or user to balance between servicing those requests and satisfying his own comfort levels. The user involvement in the decision-making process is granted by a management and control solution exploiting an innovative distributed model predictive control approach with coordination. In addition, also a hierarchical structure is proposed, to integrate the distributed MPC user-side with the microgrid control, also implemented with an MPC technique. The proposed overall approach has been implemented and tested in several experiments in the laboratory facility for distributed energy systems (Smart RUE) at NTUA, Athens, Greece. Simulation analysis and results complement the testing, showing the accuracy and the potential of the method, also in the perspective of implementation. [ABSTRACT FROM AUTHOR]

Wind technology is projected to play a key role in mitigating climate change effects and contributing to the reduction of CO2 emissions, but its sustainability critically depends on current and future climate conditions. In this study, the climate change impacts on wind resources and wind energy potential in Greece are assessed, yielding a wealth of information that could be used by stakeholders. A detailed evaluation of future wind characteristics over Greece is carried out using EURO-CORDEX RCA4 model data with a horizontal resolution of ∼12 km, taking into consideration future RCP scenarios for the short term decadal climatology of 2040, which is the expected end-life of installed wind turbines. The RCA4 model demonstrated accurate performance when compared to actual observational data from the HNMS network, thus allowing higher confidence in assessments of future periods. Future projections revealed changes in the mean wind speed of the order of ±5% that did not vary significantly for the different RCP scenarios, although on a monthly basis that variability could reach ±20%. Decadal changes in the mean wind potential were of the order of ±15% for the two RCPs (2.6 and 8.5). Wind gusts exceeding 52 m/s, linked to the wind turbine structural integrity and robust performance, appeared more frequently in RCP 8.5 by about 2–4 times per decade, affecting mostly the South Ionian Sea. The findings also indicate a tendency for calming of the "Etesians" winds over the Aegean Sea in future summers. [ABSTRACT FROM AUTHOR]

The article focuses on the relations between Greece and Israel in the military, economic and energy spheres. It states that the relationship between the two countries was improve by the deterioration of Israel's relations with Turkey and the energy resources discovered in the eastern Mediterranean. It also mentions Greece as center of natural gas exports of Israel and Cyprus to the rest of Europe.

The following scientific research discusses issues, connected to the construction of the Bourgas- Alexandroupolis petrol pipeline, from the point of view of the energy policy of the European Union (EU). The established relations between the EU and Russia lead to a demand for alternative opportunities for the construction of such infrastructure. The Bourgas-Alexandroupolis pipeline is the only infrastructural facility in this region that passes only through the territory of countries that are all members of the EU (Bulgaria and Greece). This is a circumstance that definitely makes petrol deliveries more secure. On the other hand the accomplishment of the project needs many regional ecological problems to have been solved beforehand. That's why the research's author suggests that such major investment projects of international significance are to be approved in advance by the countries from the Black sea area. Such a preliminary decision would be a guarantee for preserving the sustainable development of the Black sea. [ABSTRACT FROM AUTHOR]

The study intends to analyze the issue of European energy security from a historical perspective and also from the point of view of international relations, as well as the geopolitical, geostrategic and geoeconomic role of Turkey in shaping the European energy security complex besides the EU. Emphasizing that Turkey has the role of an "energy hub" between Central Asia-Caucasus and the EU, our research focuses on the special importance of interconnected oil and gas network projects, such as the Baku-Tbilisi-Ceyhan oil pipeline (BTC Pipeline) or the Nabucco gas pipeline and the Turkey-Greece-Italy Interconnector. [ABSTRACT FROM AUTHOR]

As the complexity of electric systems increases, so does the required effort for the monitoring and management of grid operations. To solve grid performance issues, smart grids require the exchange of higher volumes of data, high availability of the telecommunication infrastructure, and very low latency. The fifth generation (5G) mobile network seems to be the most promising technology to support such requirements, allowing utilities to have dedicated virtual slices of network resources to maximize the service availability in case of network congestions. Regarding this evolving scenario, this work presents the Smart5Grid project vision on how 5G can support the energy vertical industry for the fast deployment of innovative digital services. Specifically, this work introduces the concept of network applications (NetApps), a new paradigm of virtualization that are envisioned to facilitate the creation of a new market for information technology (IT), small and medium enterprises (SMEs), and startups. This concept, and the open architecture that facilitates its implementation, is showcased by four real-life 5G-enabled demonstrators: (1) automatic fault detection in a medium voltage (MV) grid in Italy, (2) real-time safety monitoring for operators in high voltage (HV) substations in Spain, (3) remote distributed energy resources (DER) monitoring in Bulgaria, and (4) wide area monitoring in a cross-border scenario between Greece and Bulgaria. [ABSTRACT FROM AUTHOR]

This study presents insights into the determinants of gasoline consumption for transportation based on cross section data for Greece. Given that car ownership decisions and gasoline demand decisions are taken jointly, in the empirical analysis, we employ the two-step Heckman approach. Quantile regression analysis is used to investigate disparities in behaviour among different levels of gasoline consumption. The empirical results report that demographic and economic characteristics specify the consumer's choices with respect to gasoline consumption. An energy conservation framework can improve upon the situation by facing consumers as socio-economic subgroups with different transportation needs and different lifestyle aspects. [ABSTRACT FROM AUTHOR]

In autonomous islands, the wind penetration is restricted due to technical reasons related with the safe operation of the electrical systems. The combined use of wind power with pumped storage (WPS) systems is considered as a means to exploit the abundant wind potential, increase the wind installed capacity and substitute conventional peak supply. An approach for the simulation of the autonomous electrical systems is proposed and applied in three islands. The simulation is based on the non-dynamic analysis of the electrical system, in order to calculate the energy contribution of the different power units. The aim is to analyse the prospects of WPS systems to decrease the electrical system's cost. The results show that the integration of WPS in autonomous islands may decrease the system's electricity production cost. [ABSTRACT FROM AUTHOR]

This study uses an energy flow approach to investigate the ecological sustainability of Greek agriculture. The approach is based on the analysis of ratios of energy output and energy input over a long period of time. Structural changes in land use in Greek agriculture were observed over the period 1961-98. There was an increasing trend in consumption of energy input in Greek agriculture throughout the period 1961 to 1998 as a result of diffusion of capital intensive technology. High growth in the production of energy output of cereals and vegetables was observed during the same period. The total energy output flow had a sharp increasing trend during 1961 to 1991, thereafter it declined slightly until 1998. The ratio analysis showed that the Greek agricultural system is ecologically sustainable as the energy output exceeded the amount of conventional energy required to produce it. [ABSTRACT FROM AUTHOR]

One way to perceive the electricity market is as a network of actors connected through transactions and monetary flows. By exploring the monetary flows in the electricity market, one adopts a holistic view which can provide insights on the interactions between different components of the benefits and costs, as well as on the possible conflicts or alliances between the involved actors of the system. The importance of such an analysis becomes even more evident when considering if the system's state would change due to either the effectuation of a policy measure or a shift in the external drivers of the system. Additionally, by identifying conditions of conflicting interests between the involved actors, one can devise a roadmap of least-resistance for a policy measure to attain its goals. Our work is based on the premise that understanding and quantifying the monetary flows in the electricity market can contribute to the efficiency assessment of policy interventions in the market. We present a structured analytical framework and the results of a quantitative analysis, based on available public domain data, for the identification of the main drivers and interactions that governed the major monetary flows in the Greek wholesale electricity market, from 2009 to 2013 and the ex-post assessment of the market impact of the feed-in-tariffs scheme that was in place during this period. [ABSTRACT FROM AUTHOR]