Exergy as an indicator for enhancing evaluation of environmental management performance in the hospitality industryPublished: 01 October 2018 by Elsevier BV in Journal of Cleaner Production
The importance of investigating both energy and exergy flows for assessing the environmental profile of buildings has long been acknowledged. Nevertheless, although an ample number of standalone case studies have performed energy analyses in the hospitality industry, empirical studies focusing on exergy are scarce. Extending this line of research, the present study aims to exemplify the conduct of exergy analyses alongside energy ones in optimising environmental management intelligence and improving decision making processes in hospitality accommodation. In doing so, hotels located in international tourism destinations, where tourism has a significant economic impact on the respective countries’ Gross Domestic Product (GDP), participated in the study. Energy data from two hotels situated in the Dominican Republic and, from two hotel units located in Greece was collected and analysed in a comparative manner. Findings revealed that energy flows and energy efficiency alone are not sufficient for a comprehensive assessment of hotels’ energy profiles. Thus, it is suggested that corresponding exergy flows and efficiency rates should also be estimated along with the energy ones. This study infers that location and hotel star rating classification do not seem to be key parameters in assessing lodgings’ energy quality profiles, which suggests the need for further research. The practical implications for hotel managers are also discussed.
The decomposition of CO2 emissions from energy use in Greece before and during the economic crisis and their decoupling ...Published: 01 September 2017 by Elsevier BV in Renewable and Sustainable Energy Reviews
Electrifying transportation is a promising approach to alleviate climate change issues arising from increased emissions. This study examines a system for the production of hydrogen using renewable energy sources as well as its use in buses. The electricity requirements for the production of hydrogen through the electrolysis of water, are covered by renewable energy sources. Fuel cells are being used to utilize hydrogen to power the bus. Exergy analysis for the system is carried out. Based on a steady-state model of the processes, exergy efficiencies are calculated for all subsystems. The subsystems with the highest proportion of irreversibility are identified and compared. It is shown that PV panel has exergetic efficiency of 12.74%, wind turbine of 45%, electrolysis of 67%, and fuel cells of 40%.
Lignite is by far the most used fuel in Greece for the production of electricity as there are large reserves in the country. The high emissions of global warming gases have led to the need for the adaptation of measures and initiatives to reduce emissions in the Greek energy system for the period up to 2030. It is imperative that an environmental policy and measures are implemented to limit CO2 emissions towards the Kyoto targets. The objective of this work is to analyze the environmental impacts associated with the atmospheric emissions and other wastes that are produced during the extraction, transportation, and use of lignite for electricity production in Greece using the methodology of life cycle assessment. The results presented here indicate that the most significant emission's reduction can be made from technology substitution. The introduction of advanced fossil fuel technologies can also lead to improvements in life-cycle GHG emissions. NOx, SO2, and PM emissions from the lignite life cycle, contributing to the respiratory effects impact category (21.1–28.3%), have a bigger impact than the climate change (10–32.7%) and acidification/eutrophication effects (2.17–3.82%). As per Greece's National Renewable Energy Policy the penetration of renewable energy sources in country's energy mix is investigated. © 2016 American Institute of Chemical Engineers Environ Prog, 2016
The transportation sector accounts for approximately one-fifth of global primary energy use and one quarter of all energy related carbon dioxide emissions, with nearly half of those emissions originating from passenger vehicles. In order to reduce significantly the use of fossil fuels in urban mobility, whilst improving air quality and increasing the accessibility and attractiveness of urban areas, it is necessary to increase the use of non-conventionally fuelled vehicles for passenger and freight transport in urban areas. The introduction of electric vehicles (EVs) is a promising option, so as to achieve decarbonisation objectives, energy security, improved urban air quality and to increase energy efficiency. However, there are a number of challenges for the large-scale deployment of EV both on global and European level. These, in particular, are the high cost of the battery, lack of a standardised recharging infrastructure, relatively low range of battery electric vehicles or lack of interesting value proposition for consumers. A few studies have attempted to calculate the costs and benefits of EVs, but none consider the cost and benefits of EVs at a level of detail comparable to what has been performed for other vehicle technologies. This study constructs the Total Cost of Ownership (TCO) of EVs, based on real data from the auto-industry, in order to assess the costs and benefits as well as the potentiality of electro-mobility deployment in urban areas.
Spatial Inequalities and Wind Farm Development in the Dodecanese Islands—Legislative Framework and Planning: A ReviewPublished: 16 July 2016 by MDPI in Environments
Islands present sustainable energy growth challenges due to a number of reasons such as remoteness, limited energy resources, vulnerability to external events and strong dependence on international trade agreements. In particular, the Dodecanese Islands of the Aegean Sea cover their electricity needs mostly on the basis of autonomous conventional stations, consuming significant quantities of imported oil annually. Renewable energy sources (RES) penetration increase addresses the global requirements towards a carbon neutral environment, and wind farms (WFs) are among the most well-known green electricity-production alternatives. The study explores wind power installation potential of the Dodecanese Islands and the storage or interconnection options, based on the national and European legislative framework and the international scientific literature. The major finding is that, due to the high wind potential of the area, the National policy and targets focus on the installation of great RES power at Greek islands. Hence, private interests, who are willing to carry out the electrical interconnection of islands to the mainland, serve the same objective. Both scientific and business proposals overcome the local wind power installation capacity and neglect local specifics and needs.
Life Cycle Assessment of first generation energy crops in arid isolated island states: The case of CyprusPublished: 01 April 2016 by Elsevier BV in Sustainable Energy Technologies and Assessments
The need to tackle climate change has pushed the cultivation of energy crops for the production of biofuels to the top of the global agenda. While biofuels produced from energy crops are useful for the reduction of greenhouse gases (GHGs), energy crops per se constitute a farming system that contributes to GHG emissions. The agricultural sector, energy crops included, accounted for an estimated emission of 6.1 Pg CO2 equivalents per year in 2005. The main goal of this study is the development of a consistent methodological approach to quantify the environmental impact of first generation energy crops under the conditions of arid isolated island states, by utilising Life Cycle Assessment (LCA). Comprehensive data regarding the cultivation of maize, sweet sorghum, winter wheat, sugar-beets, potato and winter barley in Cyprus are analysed with the aim to quantify their environmental impact. The study was based on primary data retrieved from pilot studies of energy crops conducted by the Agricultural Research Institute (ARI) in Cyprus. The total environmental impact of the examined crop systems for the production of 1 MJ of crop product was calculated using the CML 2001 methodology and the GaBi software. A comparison of the obtained results with the typical GHG emissions reported in the Renewable Energy Directive (RED) and other studies was carried out.The environmental impact of the investigated crop systems is presented by means of six impact categories: global warming potential (GWP 100 years), acidification potential (AP), eutrophication potential (EP), ozone depletion potential (ODP) and abiotic depletion potential (ADP-fossils). Barley, potato, and wheat crop presented the highest impact. Lower GHG emissions were obtained for wheat and maize crop systems compared to the reported emissions in the Renewable Energy Directive (RED).
Highlights•The implementation of the environmental issue to the exergy-based methods is discussed.•Exergoenvironmental analysis for the compression refrigeration machines is applied.•The effect of the selected eco-indicators to the results is evaluated.•The component-related environmental impact is negligible compared with the environmental impact of fuel. AbstractAn exergoenvironmental analysis is conducted at the component level of a system and identifies (a) the relative contribution of each component to the environmental impact associated with the entire system, and (b) options for reducing the environmental impact associated with the overall system. In an exergoenvironmental analysis a one-dimensional characterization indicator is obtained using a Life Cycle Assessment (LCA). An index (a single number) describes the overall environmental impact associated with system components and exergy carriers. It should be mentioned that the evaluation of environmental impacts would always be subjective to some degree. The paper discusses the effect of the indicator used in an exergoenvironmental analysis on the conclusions obtained from the analysis using a compression refrigeration machine as an example. The results demonstrate that the contribution of the component-related environmental impact can be neglected in the exergoenvironmental evaluation, and that only the environmental impact associated with the exergy destruction should be considered in the analysis. For the case study reported here, the conclusions extracted from the exergoenvironmental evaluation are independent of the employed environmental indicator.
Integration of the environmental management aspect in the optimization of the design and planning of energy systemsPublished: 01 November 2015 by Elsevier BV in Journal of Cleaner Production
Nowadays, the intensive use of natural resources in order to satisfy the increasing energy demand suggests a threat to the implementation of the principles of sustainable development. The present study attempts to approach thermodynamically the depletion of natural resources in the methodological framework and the principles of life cycle assessment (LCA).
Smart energy regions are defined as regions that offer maximal quality of living to their inhabitants with a minimal consumption of energy by intelligently joining of infrastructure (energy, mobility, transport, communication, etc.) on different hierarchical levels (building, district, city). The development of insular energy systems into smart energy regions, due to their special character, is presented with some challenges. The focus of this article is on presenting the potential of insular energy systems transforming into smart energy regions. Insular energy systems are defined based on data retrieved from Energy Information Administration (EIA) and classified according to their size and the nature of their isolation. In terms of this study, two novel indexes are introduced: the necessity index, which quantifies the need, and the ability index, which represents the capability of an insular energy system to develop into a smart one. These indexes are defined for those insular systems that are considered potentially upgradable. The analysis revealed that the main prerequisites to achieve the development of insular energy systems into smart ones are the reduction of GHG emissions, the introduction of political obligation toward promoting environmentally friendly policies, and the increase of RES utilization for energy production.
Buildings contribute almost half of the world's carbon dioxide (CO2) emissions. Energy and water consumption are some of the largest and fastest growing pressures on the global environment. The use of energy is mainly attributed to the heating and cooling of buildings. The type of materials used in the construction of buildings plays a significant role in the life-cycle emissions of each dwelling. Changing the material use in the construction of an existing building and adding insulation could have a major impact on energy use and the environment of the building in its entire life cycle. This paper investigates the amount of exergy savings and the decrease in CO2 emissions resulting from the refurbishing of an existing building in Ljubljana. This study results from the growing awareness that in the choice of building materials, the designer must consider not only the requirements of the owner and occupier of the building, but also the resulting energy savings, the resource base and the effects of the manufacturing and processing of building materials on the environment. The exergy efficiency of the material use is calculated and the environmental impact assessment of energy and material use is accounted for.
Low-enthalpy geothermal resources for electricity production: A demand-side management study for intelligent communitiesPublished: 01 November 2013 by Elsevier BV in Energy Policy
Sustainable Development (SD) is a very commonly used phrase in the political agenda of all European countries and in the bussiness agenda of many corporations. SD as it has been defined my the Brundland report, is not a luxury anymore, it has become a necessity for our planet to keep its existence as we know it. It is necessary to apply various policy decision tools in order to reach the required objectives on all the three pillars of sustainable development, i.e. environment, economy, society. Life Cycle Assessment (LCA) is one of those tools necessary to make the right policy decisions concerning the environmental part of sustainable development. Since LCA takes into consideration the whole life cycle of a product, it could also be used not only as a tool but also as a way of thinking, leading to playing a very important role in strategy orientation. The development of new products, the operation of existing processes, the operation of the public and the private sectors, need LCA to reach decisions that will have a minimum or no impacr to the environment. The objective of this work is to show the importance of LCA and its necessity for all policy decisions.
The efficient use of renewable energy sources (RES) is one of the major issues in the modern energy sector. The objective of this work was to examine the potential of wind energy, solar energy (e.g., photovoltaics), and biomass energy sources to meet the current energy use in the island of Lemnos in Greece. An optimization methodology was applied to the energy system of the island, where various RES are abundant and could be exploited to satisfy part of the island's energy needs. An optimization model has been developed having as an objective the satisfaction of Lemnos Island energy needs from RES taking into consideration a multiplicity of criteria such as environmental impacts, energy demand, energy cost, and resources availability. A series of solutions have resulted, based on deterministic model runs, providing decision makers the flexibility to choose the appropriate solution based on the given situation.
Comparative economic and environmental analysis of conventional, hybrid and electric vehicles – the case study of GreecePublished: 01 August 2013 by Elsevier BV in Journal of Cleaner Production
Plug-in hybrid electric vehicles as well as electric vehicles are recognized as one of the most promising avenues to materially reduce automobile contributions to petroleum dependency, air pollution and carbon dioxide emissions. Based on published data from various sources an economic and environmental comparison of a conventional, hybrid and electric vehicle – currently available at the Greek market – is performed. The production and utilization stages of the vehicles are taken into consideration. Three different electricity generation scenarios-high, medium and low carbon – are investigated. According to the comparison hybrid and electric cars exhibit advantages over conventional. In a carbon free electricity generation scenario the environmental benefits of electric cars are significant since 55.2% of the total Greenhouse gas emissions and 61.4% of the total Air Pollution emissions are stemming from conventional car; whereas 6.85% and 5.76% of total air emissions produced are emanating from electric car. It is shown that the environmental impact of electric car use depends on the source of electricity. Furthermore, three scenarios regarding the penetration rate of alternative energy propulsion systems into the Greek market are investigated for the years 2012–2025.
Granitoid rocks belonging to plutons of Greece, covering a wide range of compositions and rock-types, have been studied for their specific activity (Bq/kg) of (238)U and (226)Ra from (238)U radioactive series and (228)Ra and (228)Th from (232)Th radioactive series by using gamma-ray spectroscopy. Results on the radioactive secular equilibrium of both (238)U and (232)Th radioactive series are presented by studying the (226)Ra/(238)U and (228)Ra/(228)Th ratios. The majority of the samples are in radioactive secular equilibrium for (226)Ra/(238)U ± 1σ. However, several samples exhibit (226)Ra/(238)U ratios significantly different from 1. The distortion of the secular equilibrium in the (226)Ra-(238)U isotopic system of those samples has occurred over the last 1 Ma, and can be associated with post-magmatic processes, mainly rock-water interactions. All studied samples have (228)Ra/(228)Th ratios equal to unity ±1σ. Consequently, they can be considered to be in secular equilibrium for the last 40 a.
Exergy analysis and life cycle assessment of solar heating and cooling systems in the building environmentPublished: 01 September 2012 by Elsevier BV in Journal of Cleaner Production
Global carbon dioxide (CO2) emissions reached an all-time high in 2010, rising 45% in the past 20 years. The rise of peoples’ concerns regarding environmental problems such as global warming and waste management problem has led to a movement to convert the current mass-production, mass-consumption, and mass-disposal type economic society into a sustainable society. The Rio Conference on Environment and Development in 1992, and other similar environmental milestone activities and happenings, documented the need for better and more detailed knowledge and information about environmental conditions, trends, and impacts. New thinking and research with regard to indicator frameworks, methodologies, and actual indicators are also needed. The value of the overall indicators depends on the production procedure of each material, and indicates their environmental impact. The use of “exergy indicators” based on the exergy content of materials and the use of the second law of thermodynamics in this work presents the relationship between exergy content and environmental impact.
Integrated solid waste management and energy production - a life cycle assessment approach: the case study of the city o...Published: 01 May 2012 by Elsevier BV in Journal of Cleaner Production
The words “Sustainable Development” are frequently used by very lightly, to the extent that they have lost their meaning. There is a presumption that for any perspective analysis or any development proposal, these two words are the most appropriate. Sustainability has been incorporated in the objectives of many studies. The historical model of industrialized societies in the 19th and 20th centuries served as the central notion of what constitutes development in both the cost-effectiveness and equity perspectives. According to some analysts, this path represents the model for global prosperity. However, a number of growing parallel literatures recognize the importance of diverse development pathways in achieving an environmentally and socio-economically better world. The term sustainable development does not bring forward all aspects of development. A new term that incorporates the wellbeing of all citizens through economic development and the preservation of the environment is needed. A “Worth-living Integrated Development” could be a term that combines economic development, social development and environmental protection. A Worth-living Integrated Development may be achieved only when human societies decide to create necessary presuppositions—at the educational, research, economic, social, political, technical/technological and environmental levels—for a better world, based on the human values of peace, justice, solidarity, political, economic and social democracy and ethics, respect for nature and for the variety of cultures of all human beings.
The main objective of this work is to utilize the existing geothermal potential of the Greek island of Nisyros located in the southeastern part of the Aegean Sea for desalination of seawater. The technology most applicable for the exploitation of geothermal purposes is the multiple effect distillation process (MED). The exploitation of the geothermal hot water sources located in the island combined with an effective desalination technology can eliminate energy consumption from hydrocarbons, minimize the environmental impact and reduce dramatically the cost of fresh water. The determination of the overall environmental impact of the desalination plan by means of a Life Cycle Analysis, and the evaluation of the measure’s economical feasibility by means of Cost-Benefit Analysis and Life Cycle Cost methods will be shown. Exergy Analysis of the process will determine its thermodynamic efficiency. This work is to determine and demonstrate the feasibility of a geothermal-driven power-desalination plant to provide high quality of water in sufficient quantity at affordable costs, while protecting the fragile island environment.
A linear programming approach for the optimal planning of a future energy system. Potential contribution of energy recov...Published: 01 January 2012 by Elsevier BV in Renewable and Sustainable Energy Reviews
In this work, an analysis is being done on the concept of energy and exergy utilization and an application to the residential and industrial sector of Greece. The energy and exergy flows over the period from 1990 to 2004 were taken into consideration. This period was chosen based on the data reliability. The energy and exergy efficiencies are calculated for the residential and industrial sectors and compared to the findings of a previous study concerning the exergy efficiency of the Greek transport sector. The residential energy and exergy efficiencies for the year 2003 were 22.36% and 20.92%, respectively, whereas the industrial energy and exergy efficiencies for the same year were 53.72% and 51.34%, respectively. The analysis of energy and exergy utilization determines the efficiency of the economy as a whole. The results can play an important role in the establishment of efficiency standards of the energy use in various economy sectors. These standards could be utilized by energy policy makers. Research highlights► This work analyzes energy and exergy utilization in the energy sector of Greece by considering the energy and exergy flows for the years of 1990–2004. ► Energy and exergy analyses and hence efficiencies for the residential and industrial sector are then obtained and compared to transport energy and exergy efficiencies. ► The industrial sector appears to be the most energy and exergy efficient one. ► It should be noted that due to non-availability of data concerning the fuel energy consumption of the appliances as well as of industrial processes, a general methodology was employed in order to calculate the energy and exergy efficiencies. ► It may also be concluded that the exergy analysis offers constructive suggestions for the optimization and improvement of the energy utilization effectiveness of the sectors under study.
Application of life cycle assessment and exergy analysis in a combined cycle power plant using natural gas at Lavrion, G...Published: 01 January 2011 by Inderscience Publishers in International Journal of Power and Energy Conversion
The utilization of wind energy has been the outmost energy objective of many countries in the EU in the past two decades. The low value of its reliability factor constitutes the biggest drawback for its use. The instability of wind speeds may lead to over-production of electricity from wind power generators at one time, and lack of production to satisfy demand at others. An energy carrier such as hydrogen would play a significant role in increasing the reliability of wind power generation systems. There are two objectives of this work; the first one is to investigate the possibility that hydrogen could be technically and economically produced by wind energy, according to up-to-now scientific research, in order to increase the wind energy penetration percentage in weak electric systems. A concise description of problems that result from wind integration in the systems of high wind penetration is enterprised, also referring to the existing solution suggestions, one of which is the production of hydrogen. The role of hydrogen in high wind penetration systems is described as well, and finally, a preliminary techno-economical case study of an electrolysis unit installation in an existing wind park in Crete island is also presented. The second objective is to examine and analyse thermodynamically, the efficiency along the hydrogen and electricity production cycle, starting from the kinetic energy of the wind. The change of exergy due to losses at different points is being mapped and mathematically calculated. It is shown that there is a two fold change in exergetic efficiency along both paths. The same case study of the wind farm is taken as a system for examination. All the data used in this work come from Greece, specifically the island of Crete.
The energy use in the building sector for space heating, cooling and water heating, in the European Union Based, reaches the level of on 40% of the total used energy. The building sector is the biggest user of energy, having surpassed the transportation and industry sectors. Additionally, the energy transformation processes and the use of energy are responsible for 94% of the total emissions of CO2, with 45% coming from the building sector. The applicability of solar cooling in Greece was investigated in a medical centre in Igoumenitsa. The use of thermal solar system in the medical centre creates significant environmental benefits in the area of climate change with the reduction of CO2 emissions. The investment cost of such a solar thermal system (70 kW, AB absorption technology and a collector area of 291 m2) reaches the level of 600€/m2 of solar collector area.
The optimal use of renewable energy sources—The case of the new international “Makedonia” airport of Thessaloniki, Greec...Published: 01 August 2010 by Elsevier BV in Renewable and Sustainable Energy Reviews
Energy requirements in Greece have been continuously increasing in the past three decades. The share of renewable energy sources use has not kept up with the increase in energy demand. As a result more and more conventional energy sources are used and in this case lignite which is an indigenous source of energy and natural gas, imported from Russia. This energy picture leads towards a greater environmental impact due to the increase of pollutants to the atmosphere. It has been the objective of the European Union to satisfy 22.1% of its electric energy needs by the year 2010 with renewable energy sources. In the year of 1997 only 13.9% were satisfied with renewable energy. For Greece the corresponding figure was 8.6%. Renewable energy sources could cover a major part, if not all, of Thessaloniki's âMakedoniaâ airport needs, following the promising results of the recent renewable energy sources exploration in the region. The airport âMakedoniaâ is located a few kilometres south of the city of Thessaloniki on the coastline of Thessaloniki's bay. In this work an optimization model has been developed to determine the optimum share of renewable energy sources in various end-uses such as heating, cooling, and lighting. In this model the reliability and environmental parameters were taken into consideration. The renewable energy sources include solar energy, geothermal energy and biomass.
Multicriteria analysis of Renewable Energy Sources (RES) utilisation in waste treatment facilities: the case of Chania p...Published: 01 January 2010 by Inderscience Publishers in International Journal of Environment and Waste Management
Exergy analysis in a wind speed prognostic model as a wind farm sitting selection tool: A case study in Southern GreecePublished: 01 November 2009 by Elsevier BV in Applied Energy
In the present paper, the wind potential of Central Peloponnese in Greece has been studied and the Exergy Analysis methodology was implemented as a wind farm sitting selection tool. The wind speed of the chosen regions of Central Peloponnese was studied and correlated based on the measurements of three specific sites in the wider area using a software based prognostic model using intercomparisons of cross-predictions among these sites. The Exergy Analysis implemented in this innovative wind speed forecasting model is used to identify the actual use of energy from the existing available energy and to evaluate the proposed sites appropriate for wind farm development ending up to an accurate wind map of the area.
Carbon sequestration refers to the provision and safe storage of carbon dioxide that otherwise would be emitted to the atmosphere. The basic idea is the retention, isolation, and final storage of the produced carbon dioxide, utilizing biological, chemical, or mechanical routes. Some methods retain the carbon from the exhaust gas before it is emitted. The retained carbon then can be deposited in underground geological repositories or in the oceans. Additionally, chemical and biological processes can transform carbon into solid products or they can enhance the natural terrestrial cycle. Carbon sequestration can be a useful tool in the minimization of the carbon emissions from fossil fuel combustion and it can be significant in the stabilization of the atmospheric CO2 concentration.
A growing number of regulatory interventions such as the European Union's Extended Polluter Responsibility Policy hold manufacturers accountable for the damage inflicted to the natural environment by their products. However, not all components of an industrial product have an equitable role regarding their overall burden to the environment. In this context, it is of great interest to manufacturers to identify and rank those components with the highest potential value at the end of their useful life, employing an array of economical and environmental criteria. In order to assist manufacturers on their decision-making for the optimal end-of-life alternatives for their products, the “Multicriteria Matrix” methodology has been developed. The methodology relies on multicriteria analysis and takes into consideration the residual value, environmental burden, weight, quantity and ease of disassembly of each component. With the developed methodology only those components that do not have any residual value end up in landfills, while the majority of the components are either reused or recycled. The application of the developed methodology is demonstrated employing a real-world case study; that of an ISDN network terminal. Finally, the paper is concluded by presenting interesting managerial insights that were obtained.