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The development of clean energy has made the green finance market attractive to investors, but existing studies lack an analysis of the impact of uncertain environmental shocks on the volatility of green finance stocks. This paper focuses on the impact of major events on clean energy stock returns by using a mixed-frequency model. Specifically, to identify asymmetric effects and extreme information spillovers, we construct extreme positive returns/positive returns and extreme negative returns/negative returns, respectively. The in-sample findings suggest that asymmetric effects and extreme shocks contain valid information about future clean energy stock price volatility. The out-of-sample analysis shows that the extended model can successfully predict the volatility of clean energy stock markets. More importantly, the extended model can generate predictive gains from both statistical and economic aspects. This study can provide a reference for implementing and adjusting energy policies, which is important for optimizing the energy structure and developing the green energy industry. • This paper investigates the performance of the extended GARCH-MIDAS model. • Extreme shocks have different effects on the clean energy stock markets volatility. • The model with long and short-term extreme shocks has better predictive power. • The predictability of extreme shocks is robust by several robustness checks. [ABSTRACT FROM AUTHOR]

Hydraulic structures can be a promising place for tidal energy extraction due to the high flow velocities, easy access to the power grid and easy access for maintenance. However, quantification of the impacts of a tidal power plant in a hydraulic structure is not straight forward. In 2015 a pilot plant consisting of an array of five Tocardo tidal turbines was installed in the Eastern Scheldt Storm Surge Barrier in the Netherlands. This pilot was accompanied by monitoring studies to verify that the operation of the plant had no adverse impact on the barrier and its surroundings. This paper presents the assessment of the hydraulic impact of the tidal power plant in the storm surge barrier based on an analysis of water level and current measurements, combined with numerical modeling and followed by an assessment of the environmental impact with emphasis on the effects on the intertidal areas in the estuary. This validation approach by a pilot plant is imperative to understand the interaction between tidal turbines and the hydraulic structure on the local scale. This understanding gives extra credibility to the predictions of the extrapolated large-scale and large array assessments which will always be fully numerical. [ABSTRACT FROM AUTHOR]

The oscillating-water-column (OWC) system is one of the most developed wave energy conversion technologies, and several prototypes have been deployed and tested on the sea. Noise emission is essential to this technology's long-term environmental impact assessment. The power take-off system of an OWC comprises a self-rectifying air turbine that directly drives an electrical generator. The paper compares the noise emission of a biradial turbine with that of a Wells turbine. The noise emission of the biradial turbine was measured at the Instituto Superior Técnico variable-flow test rig, while the Wells turbine data were collected in the literature. Acoustic measurement procedures followed the guidelines of the ISO 3746 Standard. A definition of specific noise level is used to compare the noise emission from geometrically similar air turbines or other air turbines performing the same duty. The results show that the noise levels of the biradial turbine are significantly lower than those of the Wells turbine at off-design conditions for the same pneumatic power. • Methodology for measuring noise emission from air turbines. • Experimental characterisation of the acoustic emission of a biradial turbine. • Use of a specific noise level to compare air turbines. • Comparison of noise emission of a biradial turbine with a Wells turbine. • Wells turbines are significantly noisier than biradial turbines at off-design conditions. [ABSTRACT FROM AUTHOR]

The choice of a power plant in different nations depends on the required resources availability, abundance, and reliability. It is evident that renewable energy generation resources provide a more sustainable solution than the fossil fuels. However, as a complete system, renewable energy generation systems also have some overall environmental impacts on humankind and ecosystems. The main objective of this paper is to addresses the environmental effects caused by different types of renewable energy generation systems through process-based life-cycle impact analysis. A comparative study is carried out among different renewable energy generation technologies which include wind, photovoltaic, biomass, and hydro power. Life-cycle impact analysis has been carried out by Institute of Environmental Sciences (CML), Eco-indicator 99, Cumulative Energy Demand (CED) and Ecopoints 97 approaches. The superiority of this work is creating a comprehensive life-cycle inventory following a reliable global database, assessing the impacts for about 10 midpoint impact categories and three endpoint indicators, and taking account of the fossil-fuel-based energy consumption rate of each plant. The key findings reveal that photovoltaic power plants have the highest environmental impacts in the types of ozone layer depletion, fresh water aquatic ecotoxicity and marine aquatic ecotoxicity, while biomass plants impact on the categories of abiotic depletion, global warming, photochemical oxidation, acidification, and eutrophication. Moreover, the wind power plants have the more significant environmental effect on human toxicity and terrestrial ecotoxicity types. Overall, hydropower plants are found to be much more environment-friendly than other renewable electricity generation systems. [ABSTRACT FROM AUTHOR]

A novel energy index to assess plants capable of producing electricity from a renewable source is introduced in this paper. This index allows to evaluate the bidirectional energy flows on the external power grid, due the electricity exported to the grid from a renewable-based system and the electricity imported from the grid, in comparison to the electricity demand of a building. In this paper, attention is focused on a solar photovoltaic (PV) system satisfying the energy demands of an office building. Electricity from the solar PV system is partly used to operate a ground source heat pump to meet space heating and cooling demands, and partly used for other electrical loads. An energy, economic and environmental impact analysis of the proposed system is also reported. A sensitivity analysis varying the photovoltaic system capacity (2.5–10.0 kW) and the battery storage size (3.2–9.6 kWh) is also carried out. A saving in terms of primary energy and a carbon dioxide emission reduction can be obtained by a renewable-based system compared to a conventional one consisting of a natural gas fuelled boiler for space heating, an electric chiller for space cooling and the national power grid for electricity demand. • Dynamic simulation by means of TRNSYS of a PV-GSHP-based system. • Thermo-economic analysis of PV-GSHP-based system for an office application. • Increase the on-site use of PV generation limits the impact on the electrical grid. • Share of renewables on office building load can reduce national fossil-fuel demand. • Introduction of a novel energy index to assess the impact of renewables in electricity sector. [ABSTRACT FROM AUTHOR]

In view of the climate crisis, the development and the path of growth and expansion of renewable energy systems is an urgent task, but must carried out with great care on environmental compatibility and protection. Renewable energy supply systems that are suitable for grid-bound heat supply, particularly in urban areas in Europe, are geothermal binary plants that provide power as well as power and heat. This paper will present studies whose objective was the assessment of hydrogeothermal power and heat generation in low-enthalpy regions from the environmental standpoint. The German Environment Agency published results of a network of studies conducted between 2008 and 2016 on the analysis of detailed and comprehensive environmental impacts of the geothermal energy generation in Germany and has continuously evaluated these findings. In this article, the results of the Life Cycle Assessment are discussed, taking into account all effects and material flows within the entire life cycle. Based on these balances, differing geothermal systems are compared to each other and to other renewable and fossil energy generation systems in order to assess the ecological advantages and disadvantages of these systems. Taking into account local environmental impacts as well a comprehensive ecologic evaluation of potential environmental and human health impacts becomes possible. The paper presents the results of a) the mass and energy fluxes of the process chain along the life cycle, and b) the local environmental impacts along the life cycle with regard to the environmental indicators of these cases. The focus is on the impact of site and plant parameters. Concluding, it can be summarised that geothermal power and heat generation is a very low-carbon technology and can contribute to a sustainable energy supply. Hydrogeothermal plants show a significantly low surface consumption, and environmental impacts are only locally relevant and technically controllable. Through the development of optimised overall concepts, geothermal based power and heat generation can achieve minimal environmental impacts in all areas. The combined heat and power generation from geothermal resources is by far the most environmentally and climate-friendly energy supply compared to all other regenerative and fossil systems. [ABSTRACT FROM AUTHOR]

After the strategic concept of global energy Internet constructed, it has produced a strong response in the world. In recent years, countries around the world are actively promoting energy transformation and have developed clean energy development goals and plans. This paper constructs a comprehensive evaluation index system for the level of clean energy development by considering policies and regulations, energy supply, environmental impact, energy consumption, technology, economy and so on. At the same time, China, Germany, the United States and other countries are selected as evaluation objects. On the basis of searching, processing and analyzing a large number of data, firstly, the research uses the principal component analysis method to carry out the correlation cluster analysis of the index and then uses the rough set method to assign the weight of the extracted principal components. Finally, the weight of each index in the index system is calculated. The results of the comprehensive evaluation of each country are compared and analyzed, which shows that the weight determination method based on rough set theory and principal component analysis is more reasonable and objective. At the end of the paper, some suggestions are proposed to promote the development of clean energy. [ABSTRACT FROM AUTHOR]

Biogas is the gas produced by the anaerobic degradation of organic matter. In addition to the usual uses in burning, it has widespread applications as a raw material in some industries. The biomass of organic matter decomposition is a good fertilizer for agriculture. Unfortunately, despite such a large potential for reasons such as the cheapness of energy in Iran, the use of this benefical capacity has not been addressed so far. This paper investigates the potential of biogas production from poultry manure sources in Iran and demonstrates the examples of biogas plants in Iran. Also, the information about the capacity of biogas production has been investigated and reported in different provinces in Iran. The results consist of economic analysis as the cost of biogas production, and the environmental analysis as the environmental impact of the biogas production and carbon footprint. Kermanshah, Chaharmahalbakhtiari, Golestan, Bushehr and North Khorasan provinces have the highest capacity for biogas production from poultry manure. The highest cost savings by using the biogas are in Khorasan Razavi and Isfahan provinces and the lowest levels have been found in Ardebil and North Khorasan provinces. • Biogas production potential from poultry's manure resource in Iran is investigated. • Energy, Economics, Exergy, and environmental impacts analyses are performed. • Footprint analysis is performed for monitoring impacts on sustainability. • Share of poultry's manure in natural gas demand of each province is predicted. • Good results related to energy saving, costs, environmental issues are achieved. [ABSTRACT FROM AUTHOR]

Abstract The purpose of this paper is to present an integrated life cycle assessment of the electricity grid of Greece, considering the different power generation technologies currently operating in the country and the interconnected electricity transmission system. The energy and environmental assessment of both the generation and transmission systems is carried out employing SimaPro 7.1 Life Cycle Assessment software. The present work shows that the main, environmentally adverse, impacts (>60%) are associated with the electricity generation sector; in particular, with the system of mainland Greece, which is dominated by centralized fossil-fuelled power plants. Transmission of electricity was found to have 70%–90% lower life cycle impacts compared to generation. Transmission power losses are the most important contributor to GHG emissions, whereas transmission lines infrastructure and transformers are associated with much lower life cycle impacts. Findings concerning the primary energy demand exhibit analogous behaviour. Future electricity supply mixes with high shares of renewables could lead to substantially lower GHG emissions, whilst primary energy demand is expected to increase, due to the electricity intensive construction stage of renewables. Results concerning the contribution of electricity generation and transmission to environmental impacts related to human toxicity, ecosystem quality, resources depletion, etc., are also reported and discussed. Graphical abstract Image 1 Highlights • LCA is used to assess the environmental performance of Greek electricity system. • Power generation stage is the most important contributor to GHG emissions. • Electricity transmission has 70–90% lower life-cycle impacts than generation stage. • Significant sources of GHG emissions and PER are power transmission lines losses. • Future RES electricity generation will reduce GHG emissions but increase PER. [ABSTRACT FROM AUTHOR]

Abstract The feasibility of a tidal plant is assessed by studying the stream velocities, the hydrodynamic impacts and disturbances in the marine environment. However, as these technologies approach a commercial stage, it is important to assess the feasibility of injecting energy into the grid in a cost-effective way. Finding available transmission infrastructure and capacity is now one of the main barriers for renewable energy development. In this paper we assess the power potential of the Chilean Chacao channel and model the power evacuation impacts on the electric grid of the surrounding area in order to assess whether tidal plants in such isolated area are technical and economically feasible. Data obtained from direct measurement and hydrodynamic simulations is used to evaluate the electric power available through one year. The injection of power is simulated using a nested Newton-Raphson power flow solver that gives voltage and power flow changes as the tides evolve considering the characteristics of the grid. We found that a pilot project of 2.4 MW can produce 11.2 GWh per year, injecting in a 23 kV line. The region can integrate 7.4 MW without significant impact. Beyond this capacity, expensive reinforcement along the transmission system is needed. Highlights • A numerical assessment of the power extraction potential of the Chilean Chacao channel is presented. • The model uses data from direct measurements and classic harmonic analysis. • Interconnection alternatives for three tidal farms where designed and analyzed. • The power flow and voltage levels of the grid were assessed with a nested Newton-Raphson algorithm. • The neighboring electric grid can successfully interconnect a 8.4 MW tidal farm. Bigger farms impact significantly the grid. [ABSTRACT FROM AUTHOR]

In the field of renewable energy, reliability analysis techniques combining the operating time of the system with the observation of operational and environmental conditions, are gaining importance over time. In this paper, reliability models are adapted to incorporate monitoring data on operating assets, as well as information on their environmental conditions, in their calculations. To that end, a logical decision tool based on two artificial neural networks models is presented. This tool allows updating assets reliability analysis according to changes in operational and/or environmental conditions. The proposed tool could easily be automated within a supervisory control and data acquisition system, where reference values and corresponding warnings and alarms could be now dynamically generated using the tool. Thanks to this capability, on-line diagnosis and/or potential asset degradation prediction can be certainly improved. Reliability models in the tool presented are developed according to the available amount of failure data and are used for early detection of degradation in energy production due to power inverter and solar trackers functional failures. Another capability of the tool presented in the paper is to assess the economic risk associated with the system under existing conditions and for a certain period of time. This information can then also be used to trigger preventive maintenance activities. [ABSTRACT FROM AUTHOR]

Recognized as one of the most mature renewable energy technologies, wind energy has been developing rapidly in recent years. Many countries have shown interest in utilizing wind power, but they are concerned about the environmental impacts of the wind farms. The continuous growth of the wind energy industry in many parts of the world, especially in some developing countries and ecologically vulnerable regions, necessitates a comprehensive understanding of wind farm induced environmental impacts. The environmental issues caused by wind farms were reviewed in this paper by summarizing existing studies. Available mitigation measures to minimize these adverse environmental impacts were discussed in this document. The intention of this paper is to provide state-of-the-art knowledge about environmental issues associated with wind energy development as well as strategies to mitigate environmental impacts to wind energy planners and developers. [ABSTRACT FROM AUTHOR]

Researchers have shown growing interest in the development of traditional Savonius turbine due to their numerous benefits such as structural simplicity, self-start ability, relatively low operating speed, bi-directional rotational ability and lower environmental impact. However, Savonius turbines exhibits lower efficiency as compared to other similar marine current turbines. This paper proposes a novel design concept for the Savonius turbine. In addition, this work investigates flow and pressure distribution around the buckets of novel rotor with a two-dimensional unsteady numerical model. The proposed marine current turbine with novel design is named as Reza Turbine. Numerical model employed the Dynamic Mesh Method (DMM) for modelling mesh movement around the blades of rotor for different position with respect to computational domain. Developed numerical model solves the unsteady Reynolds averaged Navier-Stokes equations by using SIMPLE algorithm. In addition, we conducted an experiment in a low speed wind tunnel to obtain important performance parameters namely torque, power and performance for the proposed turbine. A set of flow speed were used as inlet boundary condition for both numerical and experimental model. A comparison between numerical and experimental results shows that the SST k-ω turbulence model gives satisfactory results for the developed novel turbine. The developed ReT is showed 52% improvement in efficiency as compared conventional Savonious turbine. Since the peak of power coefficient obtained was 0.321 for ReT, while 0.21 was reported for conventional Savonius turbine. [ABSTRACT FROM AUTHOR]

Low global warming potential R1234ze series refrigerants have been widely accepted as the working fluids for high temperature heat pump system in industrial applications. To improve the system performance of a single source R1234ze(Z) heat pump system with waste heat recovery, a hybrid source heat pump system combined with a CO 2 transcritical heat pump cycle and a R1234ze(Z) subcritical heat pump cycle is proposed in this paper. To compare the system performance of proposed hybrid source heat pump and single source heat pump systems, thermal characteristic is investigated for each system. Exergy analysis and economic analysis are also conducted to compare the system efficiencies of hybrid and single source heat pump system. The study indicates that total power consumption and heating capacities of the proposed system increase with CO 2 discharge pressure increasing. There also exists an optimal CO 2 discharge pressure for hybrid source heat pump system to achieve the best system COP. The system exergy efficiency increases with CO 2 discharge pressure increasing before it reaches to a relative stable level. Compared with the single source heat pump, both the system COP and exergy efficiency are improved by 24.8% and 27.2% at 100 °C condensing temperature. [ABSTRACT FROM AUTHOR]

A distributed energy resource (DER) system is a multi-input and multi-output energy system consisting of small-scale technologies, which provide electricity and thermal energy close to end-users. In recent years, DER systems have attracted much interest as a promising opportunity with substantial economic and environmental benefits. To reduce energy costs and environmental impact of DER systems, daily operation scheduling is crucial, and presents significant challenges even more under energy demand and supply uncertainty in presence of renewables. The contribution of this paper is to provide a stochastic programming model for the optimal operation scheduling of a DER system with multiple energy devices including renewables, considering economic and environmental aspects. To model uncertain parameters of supply and demand side, 24-h scenarios are generated by using roulette wheel mechanism and Monte Carlo simulation method. A stochastic multi-objective linear programming problem is formulated to find the optimized operation strategies of the DER system to reduce the expected energy costs and CO 2 emissions, while satisfying the time-varying user demand. By minimizing a weighted sum of the total energy cost and CO 2 emissions, the problem is solved by using branch-and-cut. Numerical results show that the Pareto frontier provides good trade-off solutions for DER system operators based on economic and environmental priorities. The total daily energy cost and CO 2 emissions under a stochastic approach result to be lower than those under a deterministic one. Moreover, the operation method provided is found to be efficient in reducing significantly energy costs and CO 2 emissions of the DER system, as compared with conventional energy supply systems and combined heat and power systems. In addition, a sensitivity analysis is also carried out to investigate the impact of renewables penetration on the economic and environmental performances of the DER system. [ABSTRACT FROM AUTHOR]

Electricity generated using photovoltaic system can only be commercial if the photovoltaic modules operate reliably for 20–25 years under field conditions. Understanding the performance degradation of photovoltaic modules is critical for optimizing its financial viability. Performance degradation of photovoltaic modules is due to multiple factors such as installation site and module technologies. In order to gain insight on performance degradation of crystalline silicon PV technology in harsh environment, a degradation effects study of c-Si photovoltaic modules in desert environment was carried. The main contribution of this paper is focused on the evaluation of c-Si PV modules performance that operated in extreme environmental conditions. This evaluation usually consists of I-V curve field measurements and visual inspections. [ABSTRACT FROM AUTHOR]

Large Wind Parks (WPs) are an essential priority, mainly in non-residential districts. Especially the offshore WPs, in areas with valuable energy potential, without legislation prohibits and without causing disturbance to the nearby community, could release enormous land for other uses (culture, recreation areas, tourism, etc.). The aim of this paper is to present a methodology for the sustainable siting of an offshore WP based on legal limitations, with a particular respect of ecological and economic resources using as example the island of Crete. It will also be considered the visual, acoustic and aesthetic disturbance of the coastal area residents and visitors and integrate them into the context. One of the essential issues that make the region unique is the undersea relief, which makes difficult the numerous and large-scale intervention, because some areas are strictly protected by the EU. Three steps have been followed: (i) exception of unsuitable areas (geological restrictions, visual and acoustical disturb and safety and of course due to environmental conditions); (ii) evaluation of environmental impacts on birdlife, Special Protection Areas and Sites of Community Importance; (iii) assessment of wind potential and needs of electricity in the regional unit of Chania, in the Western Crete. [ABSTRACT FROM AUTHOR]

Abstract: Energy from waste (EfW) has been identified as a source of ‘green electricity’ and has been used as a way of reducing greenhouse gas (GHG) emissions. Nevertheless, selecting an EfW strategy for municipal solid waste management is a challenging task not least because of the uncertainty involved in quantifying the potential economic and environmental impacts. This paper analyses five alternatives for managing the municipal solid waste of Sydney for their ‘green electricity’ and GHG savings potential under conditions of uncertainty. The impact of paper recycling on the ranking of alternatives was investigated, too. Our analysis shows that maximizing EfW generation potential does not result in greater GHG saving. A combination of food and green waste composting, recycling of metals, paper, glass and plastics while only landfilling waste fractions that are not recyclable may result in the best GHG savings. Furthermore, recycling of paper does not always achieve the best outcome; anaerobic digestion or composting may yield better results from an environmental and energy generation perspective. [Copyright &y& Elsevier]

Nowadays the biggest challenge for most organizations is a real and substantial application of sustainability through the measurement and comparability of results in order to satisfy the principles of sustainability of all the stakeholders. Definitively, it is necessary to pursue sustainability through the measurements of specific indicators and control the variables that influence the state of the economic, social and environmental issues. The aim of this paper is to contribute to the development of a comprehensive, yet practical and reliable tool for a systematic sustainability assessment , based on the Life Cycle Assessment (LCA) and the Analytic Hierarchy Process (AHP) to support decision makers in complex decision problems in the field of environmental sustainability. The results are applied to a novel compressed air energy storage system proposed as a suitable technology for the energy storage in a small scale stand-alone renewable energy power plant (photovoltaic power plant) that is designed to satisfy the energy demand of a radio base station for mobile telecommunications. The outcome is a dynamic analysis and iterative integrated sustainability assessment of corporate performance. [ABSTRACT FROM AUTHOR]

This paper applies a life cycle approach to evaluate for the first time the environmental impacts of renewable electricity in Turkey. There are 305 power plants utilising hydro, wind and geothermal resources, all of which are considered in the study. The results indicate that the impacts from large reservoir hydropower are lower than for the small reservoir (by 45%–72%) and run-of-river hydropower (by 74%–84%). The exceptions are the global warming potential (GWP) and summer smog which are two times and 45% higher for large than small reservoir, respectively. Onshore wind is the worst option overall, with nine out of 11 impacts higher than for hydropower and geothermal. However, its GWP is 9 times and 11% lower than for geothermal and large reservoir, respectively. Acidification from geothermal is 281 times higher than for wind power. Geothermal is the best option for six impacts. Large reservoir has the lowest depletion of elements and fossil resources as well as acidification. Small reservoir and run-of-river plants are the best and geothermal the worst options for the GWP. The majority of the annual impacts from the renewable electricity mix are from hydropower with the exception of acidification which is largely from geothermal electricity. [ABSTRACT FROM AUTHOR]

Sustainability trends for buildings require new construction systems to foster energy efficiency and environmentally friendly buildings. Green roofs are interesting construction systems because they provide both aesthetic and environmental benefits. This paper continues a long-term research in order to evaluate and improve the thermal behaviour and sustainability of extensive green roofs. Simultaneously this research provides experimental data for specific Mediterranean continental climate conditions. The experiment consists in evaluating the energy consumption and thermal behaviour of three identical house-like cubicles located in Puigverd de Lleida (Spain), where the only difference is the roof construction system. The roof consists of a conventional flat roof with insulation in the reference case, while in the other two cubicles the insulation layer has been replaced by a 9 cm depth extensive green roof (comparing recycled rubber crumbs and pozzolana as drainage layer materials). The electrical energy consumption of a heat pump system was measured for each cubicle during 2012 and part of 2013. Both extensive green roof cubicles show less energy consumption (16.7% and 2.2%, respectively) than the reference one during warm periods, whereas both extensive green roof systems present a higher energy consumption (6.1% and 11.1%, respectively) compared to the reference cubicle during heating periods. [ABSTRACT FROM AUTHOR]

Energy consumption in buildings accounts for up to 34% of total energy demand in developed countries. Thermal energy storage (TES) through phase change materials (PCM) is considered as a promising solution for this energetic problem in buildings. The material used in this paper is an own-developed shape stabilized PCM with a polymeric matrix and 12% paraffin PCM, and it includes a waste from the recycling steel process known as electrical arc furnace dust (EAFD), which provides acoustic insulation performance capability. This dense sheet material was installed and experimentally tested. Ambient temperature, humidity, and wall temperatures were measured and the thermal behaviour and acoustic properties were registered. Finally, because of the nature of the waste used, a leaching test was also carried out. The thermal profiles show that the inclusion of PCM decreases the indoor ambient temperature up to 3 °C; the acoustic measurements performed in situ demonstrate that the new dense sheet material is able to acoustically insulate up to 4 dB more than the reference cubicle; and the leaching test results show that the material developed incorporating PCM and EAFD must be considered a non-hazardous material. [ABSTRACT FROM AUTHOR]

The transition piece of a fixed offshore wind turbine is a reinforced part of the support structure that is connected to the wind turbine tower. These structural elements present unique features and are critical components of offshore wind turbines; designed to resist strong bending moments, shear forces and axial loads coming from cyclic environmental loads, such as wind and wave loads, acting during their complete design life of 20 years. Well designed and manufactured transition pieces with optimized ultimate and fatigue capacities, contribute to the structural soundness and reliability of offshore wind turbines. In this paper we investigate the benefits of integrating structural topology optimization in the design process of these elements, specially compared to classical design processes that are strongly based in experience and trial-and-error heuristic procedures. We first develop a solution for a 5 MW reference wind turbine with a jacket support using the classical design process and then apply structural topology optimization techniques to the same design problem. After verification of both solutions, it was found that the optimized solution is lighter and presents hot spots with lower stresses that extend its fatigue life significantly; demonstrating that an integrated design cycle that includes topology optimization can be very effective, speeding up the total design cycle and increasing the reliability of the final product. [ABSTRACT FROM AUTHOR]

The paper presents the process of choice of electricity generation technologies, which has been solved using a case of Lithuania's power sector and such multiple criteria mathematical methods as AHP (Analytic Hierarchy Process) and ARAS (Additive Ratio Assessment method). Having considered the impact of environment, a set of evaluation criteria was compiled for electricity generation technologies. Analysis of qualitative and quantitative criteria helped to rate the electricity generation technologies considering their economic, technological, environmental social and political aspects and rank them in order of priority. The derived results show that in case of Lithuania it is viable to consider further development of the nuclear power generation capacity. Among the electricity generation technologies related to renewable energy sources a clear priority is assigned to biomass technologies. Sensitivity analysis performed by applying multi criteria method ARAS, has confirmed this result. [ABSTRACT FROM AUTHOR]

The future energy system in community level should be more ‘smart’ to secure reliability, enhance market service, minimize environmental impact, reduce costs and improve the use of renewable energy source (RES). Therefore, this paper proposes an energy integration system – smart hybrid renewable energy for communities (SHREC). It considers both thermal (heating and cooling) and electricity market in a large community level and highlight the interactions between them through utilizing RES, combined heat and power (CHP) and energy storages. A planning model based on CHP modelling is developed for the SHREC system. A linear programming (LP) algorithm is developed to optimize the SHREC system in a weekly period and the results are compared with an existing energy optimization software. We also demonstrate the model in a sample SHREC system during three typical weeks with cold, warm and mid-season weather in the year 2011. The results indicate that the developed modelling and optimization method is more efficient and flexible for the smart hybrid renewable energy systems. [ABSTRACT FROM AUTHOR]

The two main processing methods for crop residue in Northeast China are stove burning for house heating and open burning as a waste product. Neither method is appropriate, as large amounts of pollutants released. This paper, therefore, proposes biomass boilers as a source for rural district heating. In a rural area in Northeast China, the PM 2.5 dispersions by the aforementioned three methods were simulated using the AERMOD model and the environmental impacts were assessed. The results show that the maximum peak concentration (MPC) is 1248 μg/m 3 for stove burning and 90,602 μg/m 3 for open burning; the general average concentration (GAC) is 345 μg/m 3 for stove burning and 1897 μg/m 3 for open burning. These concentration levels greatly exceed the thresholds established by China, the USA, and the WHO. However, the MPC for biomass boilers is only 2.76 μg/m 3 , a 99.78% and 99.99% decrease from the stove burning and open burning methods, respectively. The GAC for biomass boilers is 1.3 μg/m 3 , a decrease of 99.62% and 99.93%, respectively. Meteorological characteristics greatly influence the dispersion patterns of pollutants. In summary, replacing household heating stoves with biomass boilers is a bio-energy utilization method worth implementing widely to substantially improve the local atmospheric environment. [ABSTRACT FROM AUTHOR]

Small hydropower projects (SHPs), though generally considered more environmentally benign and socially acceptable as compared to large projects, yet their overall sustainability is under suspicion in the Himalayan regions. Almost all SHPs in this region are being developed as run of the river mode which generally causes less/no submergence and quite less displacement of people as compared to large reservoir based hydropower production mode. However, in the absence of proper planning and monitoring mechanism, these projects are causing implacable tunnelling of hills, choking of streams, conversion of streams into dry ditches and long term socio-environmental impacts. This paper presents a SHP development study from hydro rich Beas river basin of Himachal Pradesh, a state nestled in western Himalayan region of India. In depth field studies, focus group discussions with the project affected people and interaction with project proponents of five SHPs in this region suggest that sustainability issues with respect to SHPs are not small vis-a-vis size of their installed capacity. There is an urgent need to take steps to include SHPs having an installed capacity of above 10 MW into the ambit of environment clearance process which is absent in many countries of the world at present. [ABSTRACT FROM AUTHOR]

This paper seeks to analyse the differences between environmental impact assessment software tools by examining the results that they give when applied to a multi-megawatt wind turbine. Seven different life cycle impact assessment software tools are compared: CML 2001, Eco-indicator 99, Ecopoints 97, EDIP, EPS 2000, IMPACT2002 and TRACI. In Acidification and Eutrophication two groups are found: one includes the results provided by CML, Ecopoints 97, EDIP, EPS and TRACI and the other those of Eco-indicator 99 and Impact2002. In Abiotic Depletion all the results are similar except those of the EPS method, which gives negative figures. Likewise in Ozone Layer Depletion the results provided by Ecopoints 97 differ from the rest. In Human Toxicity and Ecotoxicity markedly different results are obtained by each of the LCIAs studied. In some categories major differences are found between the results provided by the 7 LCIAs examined. Which of the impact assessment software tools currently available in LCA software is chosen is therefore a critical issue. The results provided by the different software tools are not always similar, and this needs to be realised and taken into account when using the resulting data in decision-making processes. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this paper is to analyze the role of renewable energy technologies (RETs) such as biogas, improved cooking stoves (ICSs), micro hydro (MH) and solar power (SP) in helping rural communities in Nepal to adapt to climate change. The analysis considers the energy efficiency of different RETs as well as their socio-economic and environmental impacts. The efficient use of biomass in new technology, such as biogas and ICSs for cooking, has increased energy security and reduced the negative effects of traditional biomass usage. MH and SP systems are replacing candles and kerosene lamps, and are the most promising RET models for electricity generation in rural Nepal. The improved illumination from these technologies also produces better education, health, environments, and social harmony in rural communities. This study uses the Long-range Energy Alternatives Planning model (LEAP) model to develop a plan for long-term RETs use in Nepal, and specifically focuses on household energy use in rural areas. It assesses the role of biogas and ICSs in rural communities and climate change adaptation in Nepal, along with the potential role of MH and SP technologies. According to the LEAP analysis, the planned implementation of MH for 20-year long-term will result in the reduction of 2.553 million tons of CO2 emissions. Similarly SP, biogas, and ICSs will result in a reduction in CO2 emissions of 5.214 million tons, 35.880 million tons, and 7.452 million tons, respectively. [Copyright &y& Elsevier]

Abstract: The integration of wind power in power systems results in a reduction in greenhouse gas emissions. Thus, it has a positive environmental impact. However, the operation of these power systems becomes increasingly complex, owing mainly to random behaviour of the wind. In the case of island power systems, this problem is even more difficult. The traditional solution is to use diesel generators as an alternative power supply. For a wind-only power supply, an energy storage system is required. If the topography of the island makes possible the use of pumped storage hydropower plants, this is, nowadays, the most suitable energy storage system. This paper presents a novel method of Pelton turbine operation with no water flow, as a way to provide fast power injection in the case of an abrupt wind power decrease, or a wind-generator trip. This operation mode allows maximizing wind power penetration in a reliable and efficient way. This method has been validated by computer simulations, and will be tested during the commissioning of a combined wind-pumped storage power plant in an autonomous power system, on a small island. [Copyright &y& Elsevier]

Abstract: This paper considers life cycle environmental sustainability of solar water heating systems in regions with low solar irradiation, such as the UK. The results suggest that flat plate collectors have slightly lower environmental impacts than evacuated tube designs. Reducing the current energy losses of 65%–45% would reduce the impacts by around 35%. Compared to a gas boiler, solar thermal systems are a better option for only five out of 11 environmental impacts considered, with global warming and depletion of fossil resources being lower by 88% and 83%, respectively. Other impacts such as human and eco-toxicity are up to 85% higher. The solar systems score better relative to electrical water heating for eight out of 11 impacts. They are also environmentally more sustainable than heat pumps for seven categories. However, their potential is hampered because they need a back-up heating system, typically gas boiler. For this reason as well as due to a lack of suitable locations and poor efficiency, the potential of solar thermal systems to contribute to a more sustainable domestic energy supply in the UK is limited. [Copyright &y& Elsevier]

Abstract: This paper presents an investigation of the impacts of a Severn Barrage on the hydro-environment of the Bristol Channel and Severn Estuary using the Environmental Fluid Dynamics Code (EFDC) model with a recently developed Barrage module (EFDC_B). Details are given of a barrage module being implemented into the EFDC model to represent the various hydraulic structures, such as turbines and sluice gates, as deployed along the barrage line. Several cases, both with and without the barrage, have been simulated to investigate the potential changes on the peak water levels, minimum water depths and peak tidal currents arising from a barrage. The impacts of a barrage on the salinity concentration distribution have also been simulated in both 2D and 3D modes. The predicted results showed that the maximum water levels could be significantly reduced, especially downstream of the barrage and for much of the region in the Severn Estuary and that the minimum water depths would be changed so much that there would be 80.5 km2 loss of intertidal habitats due to the sitting of a barrage across the estuary. Likewise, the peak tidal currents would be considerably reduced, and by as much as a half in the middle of the main channel. The predicted salinity concentrations results indicated that at high water, the salinity concentrations would be reduced by 1–2 ppt downstream and upstream of the barrage and salinity concentrations in the region near Beachley would be reduced by up to 5 ppt, and that at low water, salinity concentrations would be reduced by 0.5–1 ppt in the middle of the Bristol Channel and by typically 0.5 ppt and 1 ppt downstream and upstream of the barrage, respectively. The predicted results also indicated that salinity concentrations downstream and upstream of the barrage would be under a stable state with slight oscillations all the time due to the effects of the barrage. A comparison between the salinity concentration distributions predicted by the 2D and 3D models indicated that the two models produced similar salinity distributions, especially in the Severn Estuary and in the region between the middle of the Bristol Channel and the seaward open boundary. [Copyright &y& Elsevier]

Abstract: Renewable energy sources and especially solar energy may be the answer to the increasing demand for energy, leading to the reduction of fossil fuel consumption and its associated negative environmental impact. An attractive solution to this problem could be the combination of renewable and conventional energy sources technologies such as the integrated solar combined cycle power plants (ISCCP). In this paper the operation of a 50 MW ISCCP with natural gas and parabolic trough solar collectors was simulated using TRNSYS software. The proposed power plant performance, fuel consumption and solar contribution were analyzed through six different simulation scenarios for different collector area. Two different modes of operation, namely power boost and fuel saving, were considered. Also, an economic analysis shows the optimal contribution rate of solar field taking into consideration the results of various simulation scenarios. [Copyright &y& Elsevier]

Abstract: Small-scale hydro or micro-hydro power has been increasingly used as an alternative energy source, especially in remote areas where other power sources are not viable. In the larger hydro projects potential energy of the water is converted to electrical power, whereas such small-scale hydro power systems utilize kinetic energy of the flow. These systems can be installed in small rivers or streams with little or no discernible environmental effects. Usually, these systems do not require a huge infrastructure like dam or major water diversions, rather use water wheels with least environmental impacts. This paper presents a report on how flow can be accelerated through convergent nozzles for run-of-river turbines in open flow channels. An existing canal in Pakistan has been used for the analysis based on its easily accessible data. The analytical and computational work presented here converts kinetic energy of water flow to electric power. [Copyright &y& Elsevier]

Abstract: Among the research activities that aim at reducing energy consumption in buildings and their impact on the environment is an experimental set-up that has several house-shaped cubicles constructed in Puigverd de Lleida (Spain). Assessing the environmental impact through studying the manufacturing, operational and disposal phases of these cubicles have been done in previous research. The objective of this paper is to investigate the use of esters as PCM in order to estimate its environmental impact in building envelopes in comparison to the use of paraffin or salt hydrates through a theoretical study. The evaluation of the environmental impact of this type of PCM material is conducted using Life Cycle Assessment (LCA) based on the Eco-indicator 99 method. It is found that the impact of ester used as PCM presents slightly better results than the case of using salt hydrates during the manufacturing impact. On the other hand, the use of salt hydrates or ester as PCM in the cubicles results in an impact reduction of 9% and 10.5% respectively, compared to the case of using paraffin. [Copyright &y& Elsevier]

Abstract: Tidal energy has the potential to play a key role in meeting renewable energy targets set out by the United Kingdom (UK) government and devolved administrations. Attention has been drawn to this resource as a number of locations with high tidal current velocity have recently been leased by the Crown Estate for commercial development. Although tides are periodic and predictable, there are times when the current velocity is too low for any power generation. However, it has been proposed that a portfolio of diverse sites located around the UK will deliver a firm aggregate output due to the relative phasing of the tidal signal around the coast. This paper analyses whether firm tidal power is feasible with ‘first generation’ tidal current generators suitable for relatively shallow water, high velocity sites. This is achieved through development of realistic scenarios of tidal current energy industry development. These scenarios incorporate constraints relating to assessment of the economically harvestable resource, tidal technology potential and the practical limits to energy extraction dictated by environmental response and spatial availability of resource. The final scenario is capable of generating 17 TWh/year with an effective installed capacity of 7.8 GW, at an average capacity factor of 29.9% from 7 major locations. However, it is concluded that there is insufficient diversity between sites suitable for first generation tidal current energy schemes for a portfolio approach to deliver firm power generation. [Copyright &y& Elsevier]

Abstract: Energy decisions play an essential role in reducing greenhouse gas (GHG) emissions in the transportation sector. Biogas is a renewable energy source and can be used as an energy source for gas-operated cars or for electric cars. This paper compares different ways to use biogas, which is produced on a medium scale anaerobic digestion plants, as an energy source for transportation. The research is conducted from an economic and environmental point of view, and the option to deliver upgraded biogas via a natural gas grid is taken into account. Different processes for the use of biogas for transportation purposes are compared using life cycle assessment (LCA) methods in the Finnish operational environment. It seems that the most economical way is to use biogas in gas-operated cars due to the high price of methane for vehicle fuel use. A new feed-in tariff for electricity produced with biogas will, however, have highly positive economic effects on electricity production from biogas. From the environmental point of view, the highest CO2 reductions are gained when biogas is used in gas-operated cars or in CHP plants for power and heat production. During the transition stage, it might be reasonable to use biogas in gas-operated cars and most importantly in heavy vehicles to reduce GHG and local pollutants rapidly. If biogas production is located near a natural gas grid, the biogas can be delivered effectively via the natural gas grid. The use of biogas in gas-operated cars is an effective way to reduce carbon dioxide significantly in the transportation sector. [Copyright &y& Elsevier]

Abstract: Wind energy development is booming worldwide with Germany and the United States being forerunners in installed capacity. Based on a review of relevant laws and regulations, policy, siting, and permitting documents, academic literature, and expert interviews, the paper compares the permit and environmental impact assessment (IA) policies and regulations pertaining to wind energy projects in both countries. The focus is on the potential of IAs in supporting an environmentally conscious development of wind power generation. This includes the analysis of IA regulations on the project level, strategic level impact assessment and planning processes, opportunities for public involvement and transparency of processes, and the clarity and predictability of the IA provisions. The findings suggest certain variations between both countries'' permit and IA processes for wind energy projects and further research needs, inter alia on the actual effects of strategic assessment of wind development on subsequent permitting. [Copyright &y& Elsevier]

Abstract: Understanding the effect of marine energy development on the underwater noise levels in a proposed installation area forms a crucial part of any Environmental Impact Assessment. This paper uses boat-based hydrophone survey data taken from an area subject to tidal currents up to 3 m s−1 and determines how the background noise levels change with tidal flow and flow direction. It was found that a more meaningful expression of background noise was gained by reference to “Power level” as measured by the Root Mean Square of the spectrum. Hydrophone measurements were taken during low season (with respect to other maritime activity) and in high season over the entire tidal cycle. Background noise levels ranged between 72 and 108 dB re 1 μPaRMS with higher sound pressure levels occurring at frequencies below 100 Hz. Background noise levels increased with increasing tidal flow and were higher on ebb tides than flood tides. [Copyright &y& Elsevier]

Abstract: The choice of which type of electrical power generation technology to adopt is driven by a number of factors including: cost of generated electricity; responsiveness of generating plant to demand; security of supply/resource availability; environmental impact; and execution risk. Within these, tidal energy is unique as a renewable technology since it has the capability of providing predictable, firm power contributing to security of supply. This predictability gives tidal energy additional value in a future electricity market. Especially one where stochastic renewable technologies contribute to a sizable component of the power supplied; and where reserve capacity is required to maintain supply during periods of non-availability. In the shorter term, in order for tidal energy to gain commercial acceptance, tidal technologies under development need to produce electricity at a competitive price. This paper examines the drivers influencing electricity pricing; current tidal energy developments, aimed at reducing capital costs; and bench-mark these against offshore wind. [Copyright &y& Elsevier]

Abstract: In promoting renewable energy options, the environmental problem of GHG emissions should not be replaced with other environmental problems. Large-scale renewable infrastructure projects in particular – from offshore wind farms to concentrated solar towers to hydropower installations – need to be accompanied by adequate environmental and social impact assessments. For policies, plans and programmes around renewable energy investments, strategic environmental assessments should be applied. Such assessments will increasingly need to consider the changing nature of supporting ecosystem services and the need for climate adaptation. Financing institutions should promote appropriate safeguards, supported by capacity building activities from international organizations, including IRENA, in order to unleash the full sustainable potential of renewable energy options. This paper explores the experiences of applying impact assessment tools and processes to renewable investments and highlights some of the key aspects which should be taken into consideration when pursuing a renewable energy future. [Copyright &y& Elsevier]

Abstract: The present work compares the environmental impact of three different thermal energy storage (TES) systems for solar power plants. A Life Cycle Assessment (LCA) for these systems is developed: sensible heat storage both in solid (high temperature concrete) and liquid (molten salts) thermal storage media, and latent heat storage which uses phase change material (PCM). The aim of this paper is to analyze if the energy savings related to the stored energy of the different systems are enough to balance the environmental impact produced during the manufacturing and operation phase of each storage system. Some hypothetical scenarios are studied using LCA methodology to point out the differences between each TES system. The system based on solid media, due to his simplicity, shows the lowest environmental impact per kWh stored of all three systems compared. In addition, the liquid media (molten salts) shows the highest impact per kWh stored because it needs more material and complex equipment. [Copyright &y& Elsevier]

Abstract: This paper attempts an integrated environmental assessment of certain crops, their products and by-products, which are promoted in Greece, as potential raw materials for liquid biofuel and low carbon energy production. The analysis is based on the experimental results of a Greek state funded research project (Hi-Bred fuels), which investigated the integrated management of energy crops for both biofuel and energy production. Four crops, some new for Greek agriculture and other indigenous, namely rapeseed, soya, sunflower and cotton, were cultivated under “real farming” conditions, keeping detailed data of all important aspects affecting their environmental profile. The main industrial processes employed in Greece for extracting, processing and esterifying vegetable oil from the oleiferous seeds were also identified and studied in detail. The data collected during the various production steps were introduced in Global Emission Model for Integrated Systems (GEMIS) software in order to create production cycle models of both non-esterified (straight vegetable oil) and esterified (biodiesel) biofuel models. Dedicated experiments were performed on a diesel passenger car in order to investigate the applicability of the final products. Results indicate that sunflower has the optimal environmental characteristics with respect to biofuel production with potential GHG savings of 58–71% depending on the end product. Rapeseed followed with GHG savings potential of 48%–62%, soyabean oil (47%–60%) and cottonseed oil (35%–47%). For the different products, and production steps, the results of the analysis for energy, CO2 equivalent emissions and other pollutant emissions are presented. Results concerning energy crops adaptability in Greek climate conditions and their product yields were quite promising, with the exception of the watering demands, which in some cases were not sustainable (GHG savings below 35%). Vehicle application results indicate that on a low level concentration (up to 10%v/v) all biofuels may be employed without important effects on vehicle emissions. Finally it is concluded that the use of residual waste biomass is a key aspect for achieving sustainable and environmentally efficient biofuels. [Copyright &y& Elsevier]

Abstract: As the demand for renewable energy increases, it becomes important to critically examine the environmental impacts of renewable energy production. Often, the approach has been trial and error in renewable energy with respect to its impact on the environment. Hydrokinetic Energy Extraction (HEE) has been seen as a potentially “benign” form of renewable hydropower. This paper provides a benchmark for initial measurement of HEE environmental impacts, since negative outcomes have been present with previously assumed “benign” renewable hydropower. A Gorlov system was used to represent a HEE system. Life Cycle Assessment (LCA) was utilized to compare the environmental impacts of HEE with small hydropower, coal, natural gas and nuclear power. Environmental Protection Agency (EPA) criteria air emissions were quantified and compared over the life cycle of the systems. Life cycle air emissions were used in combination with TRACI to compare the systems. The Gorlov system was found to have the lowest life cycle impact with a system lifetime comparison, and did compare closely with small hydropower. [Copyright &y& Elsevier]

Abstract: This paper presents the results of a study conducted at a rural (island) community to understand the role of PV hybrid system installed on an island. Until 2004, most islanders had installed diesel generators in their homes to generate electricity, which was directly supplied to appliances or stored in the batteries for later use. A field survey was carried out to study the user satisfaction of the PV hybrid system in the island community. The attitude of islanders to the PV hybrid system was mostly positive. The islanders can use more electricity, the supply of which can meet the demand. A comparison of pollutions before and after installation of the PV hybrid system was made along with the interviews with the users. The data show that the users are highly satisfied with the PV hybrid system which can reduce environmental impact, especially air and noise pollutions. New opportunities as a result of access to electric service include studying and reading at night that were not possible earlier. All the islanders use the PV hybrid system and more importantly, no one found that the system made their life worse as compared to the earlier state of affairs. [Copyright &y& Elsevier]

Abstract: Malaysia is heavily dependent on fossil fuel for electricity generation. With the rapidly diminishing of its fuel reserve and the increasingly negative effects of fossil fuels to the environment, the government has begun to utilise bio-fuel and solar radiation for electricity generation. However, the potential of harnessing other renewable sources, particular ocean energy, in Malaysia has not been fully realised. Therefore, studies were carried out to identify the potential of harnessing ocean energy for electricity generation. The Princeton Ocean Model was used to create a three-dimensional numerical ocean model for Malaysia which was calibrated against measurement by a means of adjoint data assimilation approach. A set of reliable tidal speed and tidal elevation data was therefore generated to determine the types of tides available in Malaysia, the potential areas of installing marine current turbines (MCTs), the total amount of electricity to be generated by MCT, the economical viability and the environmental benefits of using MCT in Malaysia. This paper presents the findings on the studies, encompassing the technical, economical and environmental aspects of installing MCT in Malaysia. The results are critical to policy makers and the potential investors on tidal energy in Malaysia for decision making. It may also help the neighboring countries to realize the possible potential of their ocean energy for electricity generation. [Copyright &y& Elsevier]

Abstract: The availability and reliability of wind power depend a great deal on current and future climate conditions, which may vary in light of possible global climate change (GCC). Long-term energy planning, however, does not normally take possible future GCC into consideration, which may turn out to be a risky exercise. In the case of Brazil, the untapped wind power potential is known to be impressive, provided that climate conditions remain the same over time. The focus of this study is to analyze some possible impacts of GCC on the wind power potential of Brazil, by simulating wind conditions associated with the IPCC A2 and B2 Scenarios. Results based on the HadCM3 general circulation model and the analysis of the country''s wind database indicate that the wind power potential in Brazil would not be jeopardized in the future due to possible new climate conditions. On the contrary, improved wind conditions are expected, particularly in the Northeast coast of the country. Therefore, investments in wind power generation can be an interesting way to expand renewable energy production in Brazil. However, given the large uncertainties associated with GCC models and scenarios, the findings of this paper should be viewed as a possibility rather than as a projection. [Copyright &y& Elsevier]

Abstract: This paper describes the study of the impact of energy absorption by wave farms on the nearshore wave climate and, in special, the influence of the incident wave conditions and the number and position of the wave farms, on the nearshore wave characteristics is studied and discussed. The study was applied to the maritime zone at the West coast off Portugal, namely in front of São Pedro de Moel, where it is foreseen the deployment of offshore wave energy prototypes and farms between the 30m and 90m bathymetric lines, with an area of 320Km2. In this study the REFDIF model was adapted in order to model the energy extraction by wave farms. Three different sinusoidal incident wave conditions were considered. Five different wave farm configurations, varying the position of the wave farm, its number and the width of the navigation channels at each wave farm were analysed. The results for each configuration in terms of the change of the wave characteristics (wave height and wave direction) at the nearshore are presented, compared and discussed for three representative wave conditions. [Copyright &y& Elsevier]

Abstract: The need to decrease the consumption of materials and energy and to promote the use of renewable resources, such as biofuels, stress the importance of evaluating the performance of engines based on the second law of thermodynamics. This paper suggests the use of exergy analysis (as an environmental assessment tool to account wastes and determine the exergy efficiency) combined with gas emissions analysis to optimize the performance of a compression ignition (CI) engine using biofuels such as cottonseed and palm oils, pure or blended with diesel for different engine loads. The results show that the combination of exergy and gas emissions analyses is a very effective tool for evaluating the optimal loads that can be supplied by CI engines. Taking into account technical constraints of engines, a tradeoff zone of engine loads (60% and 70% of the maximum load) was established between the gas emissions (NO and CO2) and the exergy efficiency for optimal performance of the CI engine. [Copyright &y& Elsevier]

Abstract: The use of renewable forms of energy is important throughout the world, not just in countries where there are concerns over the availability of fossil fuels. In order to develop and promote suitable energy policies for the future it is necessary to gain an understanding of stakeholder views in all countries, including those with substantial fossil fuel reserves. The volume of construction work in the Gulf Cooperation Council (GCC) countries has recently been at unprecedented levels, with a huge environmental impact from construction and also from potential future energy demands. The aim of this paper is to assess the potential to exploit use of a particular, but valuable, renewable energy option: building-integrated photovoltaics (BIPV) in those countries. Such exploitation could offset, at least in some part, the future environmental burdens. A large-scale survey, followed by a number of in-depth interviews, has been undertaken in order to examine the use of BIPV. Empirical research findings are presented, and then analysed in order to determine the current viability of a large-scale expansion of BIPV in the GCC region. The research indicates that the main factors hindering expansion are high costs and the negative public perception of BIPV in the countries concerned. Proposals are therefore provided to assist the development of suitable policies and the wider introduction of viable BIPV in the GCC markets. [Copyright &y& Elsevier]