Petrographic Characteristics of the Kardia Lignites (Core KT6A-3), Ptolemais Basin (Greece)

The aim of this study is to provide useful coal-petrographic data, which will further help the characterization, exploitation, and utilization of the Kardia lignite deposit and also initially to access the depositional conditions mainly in terms of water table level and subsidence rate of the fen substrate. Ash contents, as well as the C, H, N, O, and S were determined in nine lignite samples from core KT6A-3. The ash contents (750°C) of the studied lignite seams range among 14–37% (on dry basis). Contents of C, H, N, and O have values between 34–52%, 2.5–4.2%, 0.8–2%, and 21–30.6%, respectively. Sulfur does not exceed 1.2%. Huminite group dominates with values between 84–99 vol%, mmf. All samples display a distinct prevalence in detrohuminite (up to 82 vol%) with attrinite being most abundant. Liptinite and inertinite macerals have low contents, which do not exceed 8% and 12%, respectively. The Kardia lignites are medium to very low-grade coals. They formed in fens under limnotelmatic regime and originated from herbaceous vegetation. During peat deposition, conditions were well moist, intense reducing, and favored increased bacterial activity. The ratio of plant growth and peat accumulation versus rise of water table due to the subsidence rate was not well balanced. The petrographical composition of the Kardia lignites is related either to a long residence time of the organic matter in the acrotelm or to an herbaceous vegetation origin.     

Mineralogical characterization of the intraseam layers of Lofoi lignite deposits in Florina basin (western Makedonia,northwest Greece)

The mineralogical composition of intraseam layers from Lofoi lignite deposits (northwest Greece) is the subject of the present study. The samples were examined by means of X-ray diffraction (XRD), thermo-gravimetric (TG/DTG) and differential thermal analysis (DTA), and Fourier transform infrared (FT-IR) spectrometry. The clay minerals prevail in most samples, with illite-muscovite being the dominant phase, and kaolinite and chlorite being the other major clay components. No smectite was found. Quartz and feldspars, dominate in two cases. The studied materials are characterized as clays to clayey sands, showing significant similarities with the intraseam layers of the adjacent Achlada lignite deposits.     

The potential of district heating using geothermal energy. A case study, Greece

The purpose of this study is to investigate the possibility of using low-enthalpy geothermal energy from the geothermal field of Sousaki in the province of Korinthos, Greece, to cover the thermal needs of the nearby town of Ag. Theodori. The possibility of developing a system of district heating was examined based on a proposed town model. Total thermal demands were calculated on the basis of a model dwelling and prevailing weather conditions in the area. Subsequently, a heat transfer circuit is proposed, including the distribution network, the heat exchanger, the production and reinjection pumps, and the pumping station. Finally, energy indices are presented, such as demand in tons of equivalent oil and CO₂ emissions.     

Chemical patterns of thermal aquifers in the volcanic islands of the Aegean Arc, Greece

Thermal spring waters and associated gases discharging on several volcanic islands and on mainland Greece along the Hellenic Volcanic Arc (HVA) in the south Aegean sea have been investigated. The chemical characteristics of most of the spring waters suggest that the water in their feeding aquifers is largely derived from seawater that enters the hydrological circuits and mixes with local neutral low-salinity bicarbonate waters. There are however discrepancies between the simple theoretical mixing line between local meteoric waters and seawater, and the actual mixing line. This mixing is accompanied by partial Mg and SO₄ precipitation to secondary minerals and by the addition of K, Ca, HCO₃, B, NH₄, and SiO₂ to the solutions as a result of water-rock interaction processes.At Milos and Nisyros, where active hydrothermal systems are present at shallow depth, the silica content of the thermal springs is much higher than that of springs on the other islands and mainland Greece. This suggests higher thermal gradients at depth there, and the ascent of geothermal fluids to the surface along fractures prevalently located in the fumarolic fields within the latest eruptive centers and calderas. The fact that the springs are anomalously enriched in silica only at Milos and Nisyros suggests indirectly that, apart from Santorini island, where steam vents are present at the surface, the fluids from the active high-enthalpy geothermal systems do not rise to the surface anywhere else along the HVA. If present, they are well confined under thick and impermeable covers.     

Renewable energy sources (RES) projects and their barriers on a regional scale: The case study of wind parks in the Dodecanese islands, Greece

The increasing energy challenges faced, in particular, by isolated communities, such as insular communities, call for an integrated, flexible and easy-to-apply methodology aiming at providing a list of renewable energy sources) (RES) projects capable to reduce green house gas (GHG) emissions, satisfy future energy forecasts and reach the objectives of international/national energy directives and obligations, as, for example, the ones set by the Kyoto Protocol by 2010. The EU project EMERGENCE 2010 developed such a methodology that is implemented here in the case study of wind parks in the Dodecanese islands in Greece. The results obtained consist of a final list of financially viable RES wind projects, for which various barriers have been previously identified and assessed. The additional advantages of the proposed methodology is that besides providing as an end result a comprehensive list of RES projects adopted to specific criteria and regional priorities, it also allows space for involving – from early stages – the local community and stakeholders in the decision-making process (participatory planning); in this way, the EMERGENCE 2010 methodology may assist towards the RES promotion and public acceptance, the profitability of RES investments and the regional sustainable development.     

Multi-farm economic analysis of perennial energy crops in Central Greece, taking into account the CAP reform

This study analyses farm level economic impacts of biomass production from perennial crops including Arundo donax L. (arundo), Miscanthus x giganteus (miscanthus), Panicum virgatum L. (switchgrass) and Cynara cardunculus L. (cardoon). Regional biomass supply curves are estimated with a dynamic, multi-farm, mathematical programming model. Micro-economic data for the model are generated from farm surveys covering 52 farms containing a total of 400 parcels, in Central Greece. The study also examines the potential effects of the Common Agricultural Policy reform in 2003 on regional biomass supply. Simulations show that the policy reform toward decoupled subsidies lowers the cost of biomass between 15 and 25 euro per tonne. Switchgrass appears to be the most attractive option, followed by cardoon and miscanthus. Due to high specific machinery cost, arundo is never preferred. Relative to the agricultural policy setting of Agenda 2000, the biomass potential increases more for farms of small economic size and farms with a higher share of cotton.     

Sedimentary facies identification of the Triassic in the Hongqiba region of the Northwest margin of Junggar Basin,West China

This study determined the lithological association and identified sedimentary facies of Triassic in the Hongqiba region through analyzing core samples, wireline log patterns, and seismic facies. The spatial variation of the sedimentary system in the Triassic was then determined based on source supply and hydrodynamic conditions. Results show that the Triassic in the Hongqiba region was dominated by coarse deposits derived from fan delta deposition system, including fan delta plain, fan delta front, and pre-fan delta. Primary microfacies are distributary channel, underwater distributary channel, inter-distributary bay, and distal bar. Climate changing from drought to humidity during the Triassic resulted in widespread lake transgression.     

CO2 emissions in Greece for 1990–2002: A decomposition analysis and comparison of results using the Arithmetic Mean Divisia Index and Logarithmic Mean Divisia Index techniques

This paper deals with the decomposition analysis of energy-related CO₂ emissions in Greece from 1990 to 2002. The Arithmetic Mean Divisia Index (AMDI) and the Logarithmic Mean Divisia Index (LMDI) techniques are applied and changes in CO₂ emissions are decomposed into four factors: income effect, energy intensity effect, fuel share effect and population effect. The period-wise and time series analyses show that the biggest contributor to the rise in CO₂ emissions in Greece is the income effect; on the contrary, the energy intensity effect is mainly responsible for the decrease in CO₂ emissions. A comparison of the results of the two techniques gave an insight in the intricacies of energy decomposition. Finally, conclusions and future areas of research are presented.     

A comparative thermodynamic analysis of Kalina and organic Rankine cycles for hot dry rock: a prospect study in the Gonghe Basin

Hot dry rock is a new type of geothermal resource which has a promising application prospect in China. This paper conducted a comparative research on performance evaluation of two eligible bottoming cycles for a hot dry rock power plant in the Gonghe Basin. Based on the given heat production conditions, a Kalina cycle and three organic Rankine cycles were tested respectively with different ammonia-water mixtures of seven ammonia mass fractions and nine eco-friendly working fluids. The results show that the optimal ammonia mass fraction is 82% for the proposed bottoming Kalina cycle in view of maximum net power output. Thermodynamic analysis suggests that wet fluids should be supercritical while dry fluids should be saturated at the inlet of turbine, respectively. The maximum net power output of the organic Rankine cycle with dry fluids expanding from saturated state is higher than that of the other organic Rankine cycle combinations, and is far higher than the maximum net power output in all tested Kalina cycle cases. Under the given heat production conditions of hot dry rock resource in the Gonghe Basin, the saturated organic Rankine cycle with the dry fluid butane as working fluid generates the largest amount of net power.     

大容量新型热油蒸汽热风一体化炉三维开发设计研究

基于能源合理有效利用的观点，运用数据库管理系统、面向对象的编程技术和三维机械设计及其图像处理技术，对15．7MW大容量新型热油蒸汽热风一体化炉进行了三维开发设计分析与编程热工计算，提升了国内在热油载体加热领域的技术水平。     

北京市漫水河流域山区洪水模拟研究

北京市山丘地区洪水具有汇流快、历时短、破坏强的特点,多发于夏秋季汛期,损失惨重。为此需建立水文预报系统,采用分布式水文模型(EasyDHM)和马斯京根汇流模型演算方法分别进行产、汇流计算,模拟再现漫水河站近几十年内发生的洪水事件。结果发现,率定期参数敏感性分析和优化之后的模型模拟精度有明显提高;验证期模拟洪水发生年份距离模型率定年份越近模拟效果越好,且模拟洪水的洪量模拟效果优于洪峰模拟。     

Bacterial desulphurization of low-rank coal: A case study of Eocene Lignite of Western Rajasthan,India

High sulfur lignite samples collected from Giral mine was subjected to desulfurization using bacteria Burkholderia sp. GR 8–02 isolated from native lignite. A removal of 50.69% of total Sulfur (S_t) has been observed. The reduction in hydrogen and ash content was found up to 2.92% and 14.78%, respectively. In addition, relative carbon (up to 12.81%) and nitrogen (up to 34.52%) has also been increased. An increase in the relative concentration of volatile matter and fixed carbon (up to 19.47% & 3.29%) has been detected. In addition, the desulfurization of high sulfur lignite with Burkholderia sp. GR 8–02 increased the calorific value from 5.24% to 20.74%.     

A model for the development of a power production system in Greece,Part II: Where RES meet EU targets

This paper studies the electricity production system of the Greek Interconnected Electric System using a development model created with the software package WASP-IV. The period of study is from 2009 till 2030. It consists of three scenarios using three different criteria: energy, environmental, and economic. The three scenarios are the Renewable Energy Source (RES), the lignite–RES, and the natural gas–RES. Subsequently, a sensitivity analysis is carried out for annual growth rate of electricity consumption and load demand. It is considered that there are no other energy sources beyond those already in use (lignite, oil, natural gas, biomass, solar, wind, and hydropower), no CO₂ capture policies are implemented, and electricity production from RES meets targets of the European Union in 2020. The present paper completes the study started with the paper “A model for the development of a power production system in Greece, Part I: RES do not meet EU targets”. It is shown that with regard to fossil fuels, the use of natural gas is the best choice. The use of RES, though environmentally friendly, is an expensive solution.     

Planning globally,protesting locally: Patterns in community perceptions towards the installation of wind farms

The evidence is compelling that extended use and production of energy are globally responsible for the serious deterioration of physical environment and climate change. The further penetration of renewable energy sources (RES) emerges as a crucial factor contributing to the mitigation of global warming. Within this framework wind energy is expected to have a leading role for Greece's compliance with the EU environmental targets of 2020. However, the installation of wind parks in specific regions with high wind potential is seriously constrained by the reaction of local communities. Using a survey the present research dissects public acceptance for existing and proposed wind farms in the region of Southern Evia, Greece. Results indicate an overall support for wind energy and confirm the growing inconvenience with NIMBYism, especially in areas with existing wind parks in operation, as a theoretical framework explaining resistance to planned wind energy investments. By contrasting self-reported ex ante- and ex post-perceptions of impacts and benefits we highlight the role of experience in community acceptance of wind energy installations. Our statistical models prescribe the profile of those most probably in favour of existing installations, new installations in other parts of Evia or new installations elsewhere in Greece. Finally, we introduce the ‘Not-In-My-Front-Yard’ (NIMFY) syndrome suggesting that the impact of visibility on public acceptance is far from being a simple concept as it is linked to both a physical landscape context and socio-economic parameters.     

辽东沿海诸河流域庄河水环境容量分析

基于现有水环境容量在流域的应用,构建了控制单元划分—功能区建立—地表水环境容量核算—污染物削减量—污染管控的流域水环境管理体系,以辽东沿海诸河中污染较重的庄河为例进行流域水环境容量的研究.结果 表明,综合考虑行政区划、水文条件、监测断面、污染源分布等水环境功能条件,划分为5个控制单元和3个功能区;将最枯季水文条件下...     

Hotspots,frontiers, and emerging trends of tandem solar cell research: A comprehensive review

A tandem solar cell (TSC) is a kind of special photovoltaic (PV) device with two or further sub-cells stacked in it. On the basis of Web of Science database and CiteSpace software, the literature about TSC research from 2000 to 2019 is reviewed. The top 10 hotspots are deduced (efficiency, performance, film, silicon, design, open circuit voltage, polymer, morphology, oxide, and growth), yielding prominence of the primary roles of devices and materials in PV research. The top 10 research clusters are analyzed (organic compounds, polymer solar cells, perovskite, non-fullerene acceptors, silicon, high frequency-glow discharge, solution process, light trapping, liquid phase epitaxy, and water splitting), revealing the development orientation of TSC research. High co-citation, strong burst citation, and representative frontier literature are highlighted. Five evolution trends/clusters are examined. Organic solar cells are the mainstream of TSC research and are gradually replaced by the emerging trend of non-fullerenes. Perovskite solar cells are a typical emerging trend, which rejuvenates the traditional silicon solar cells. This review provides a visual panorama of TSC research over the past two decades.     

A model for the development of a power production system in Greece,Part I: Where RES do not meet EU targets

This paper studies the electricity production system of the Greek Interconnected Electric Production System using a model created with the software package WASP-IV. The period of study is from 2009 to 2030. It consists of three scenarios using three different criteria: energy, environmental and economic. The three scenarios are the business as usual, the lignite and the natural gas. Subsequently, a sensitivity analysis is carried out for the annual growth rate of electricity consumption and load demand. The paper examines how the three criteria change, when there are no other energy sources beyond those already in use (lignite, oil, natural gas, biomass, solar, wind and hydropower) with no CO₂ capture policies and with the electricity production from Renewable Energy Sources not to reach the targets of the European Union for 2020. In a second paper, three other scenarios examine production with the Renewable Energy Sources to reach the targets of the European Union for 2020.     

柴油机微粒和苯并（a）芘排放特性的研究

本作采用稀释取样法测量和研究了自然吸气、增压和增压中冷高速柴油机的微粒排放特性，同时对一台高速柴油机排气微粒中的苯并（ａ）芘也进行了分析研究。     

Stochastic modeling of coalbed gas content: A case from Harcourt gas field of Bowen Basin,Australia

A new method to build a stochastic model of as-received coalbed gas content was proposed, and the workflow is explained in detail in this paper. First, dry-ash-free gas content model was obtained by combining the trend property and residual property to reflect the main control factor of depth and inherent heterogeneity of coal seams. Second, ash model was converted from logging density model with relative density as an intermediate variable for overcoming the shortage of core data. Third, moisture model was built. Finally, the model of as-received gas content was obtained by a simple arithmetic conversion. This method was applied in Harcourt coalbed gas field of Bowen Basin, Australia, with a satisfactory result.     

A general technoeconomic and environmental procedure for assessment of small-scale cogeneration scheme installations: Application to a local industry operating in Thrace, Greece, using microturbines

The present paper describes a proposed general systematic procedure for small-scale combined heat and power (CHP) exploitation (where “small-scale CHP” refers to CHP installations with electric capacities up to 1 MW). The mentioned systematic procedure is implemented through a developed computer code and may be applied to any such small-scale project in order to assess its suitability based on technoeconomic and environmental considerations. A dynamic database based on small-scale CHP units (available in the world market) and their pertinent technical, economical and environmental features is created and, in conjunction with the developed program, is used for determination of a suitable CHP unit (or system) size and the selection of the associated proper prime mover type for any project of interest. Using well-known economic criteria, the economic analysis is performed, including the sensitivity analysis of the considered project based on the main key system parameters. In terms of the socioeconomic analysis, a carbon tax (CT) scenario is considered, and its effect on the economic behavior of the project is investigated. Last, with respect to environmental considerations, the program calculates, for any such project, the avoided main pollutants and the fuel savings when a CHP system is applied. As a case study, a small textile industry operating in the Eastern Macedonia-Thrace Region of Greece is considered, and its associated (electrical and thermal) data are used as input data to the proposed computer program. In this application, two microturbine units are selected and thoroughly evaluated, and the pertinent simulation results are presented and discussed accordingly.