General sustainability indicator of renewable energy system based on grey relational analysis

This research answers the question of how to measure the sustainability of a renewable energy systems (RESs) as a physical parameter. Renewable energy is considered as a solution for mitigating the energy crisis, climate change and environmental pollution; however, an important problem of its application is that it is very difficult to evaluate the sustainability of RESs. This study develops a general sustainability indicator which is a tool to evaluate sustainability of RESs precisely and comprehensively. Based on the Triple Bottom Line approach, 11 Basic Sustainability Indicators with different dimensions and various units are selected from environmental, economic and social sustainability assessment criteria. In order to deal with the uncertainties in the definition and the assessment of sustainability, the grey regression analysis method is employed to quantify the basic indicators and to aggregate them into the general indicator. In addition, for explaining application of the general indicator, the cases of four RESs in hot‐arid Australia are presented. In the case study, the grey indicator is used to assess the sustainability of four systems with different combinations of grid, solar photovoltaic and wind renewable energy. The final results are compared with the general indicator based on fuzzy sets theory developed in previous studies. It is found that for the case of Australian system, the grey sustainability indicator has a good linear correlation to the fuzzy indicator results. The grey indicator is an effective way to assess the sustainability of RESs and provides a good tool for designers, users, decision makers and researchers. Copyright © 2013 John Wiley & Sons, Ltd.     

Prioritizing sustainable electricity production technologies: MCDM approach

Economic, technological, social, and political developments stressed the need for shifts in energy-mix. Therefore it is important to provide a rationale for sustainable decision making in energy policy. The aim of this paper is to develop the multi-criteria decision support framework for choosing the most sustainable electricity production technologies. Given selection of sustainable energy sources involves many conflicting criteria, multi-criteria decision methods MULTIMOORA and TOPSIS were employed for the analysis. The indicator system covering different approaches of sustainability was established. The analysis proved that the future energy policy should be oriented towards the sustainable energy technologies, namely water and solar thermal ones. It is the proposed multi-criteria assessment framework that can constitute a basis for further sub-regional optimization of sustainable energy policy.     

Eating energy—Identifying possibilities for reduced energy use in the future food supply system

This paper explores the possibilities for reducing future energy use for eating to a sustainable level. A backcasting approach is used to generate an image of the future where energy use for eating is 60% lower in 2050 than in 2000. The currently known potential to reduce energy use in the food supply system for producing, transporting, storing, cooking and eating food is explored and described in terms of a number of distinct changes that are numbered consecutively and presented in both a quantitative and qualitative way. Sweden is used as the case and all data regarding energy use apply for Swedish conditions. An exercise like this illustrates the possible outcome of taking sustainability seriously. If sustainability is to be achieved, some images of the future are needed so that potential targets can be identified. This paper does not present forecasts, but illustrates the kind of changes needed in order to achieve sustainable energy use in the food system.     

Renewable energy technologies for the Indian power sector: mitigation potential and operational strategies

The future economic development trajectory for India is likely to result in rapid and accelerated growth in energy demand, with attendant shortages and problems. Due to the predominance of fossil fuels in the generation mix, there are large negative environmental externalities caused by electricity generation. The power sector alone has a 40 percent contribution to the total carbon emissions. In this context, it is imperative to develop and promote alternative energy sources that can lead to sustainability of the energy–environment system. There are opportunities for renewable energy technologies under the new climate change regime as they meet the two basic conditions to be eligible for assistance under UNFCCC mechanisms: they contribute to global sustainability through GHG mitigation; and, they conform to national priorities by leading to the development of local capacities and infrastructure. This increases the importance of electricity generation from renewables. Considerable experience and capabilities exist in the country on renewable electricity technologies. But a number of techno–economic, market-related, and institutional barriers impede technology development and penetration. Although at present the contribution of renewable electricity is small, the capabilities promise the flexibility for responding to emerging economic, socio–environmental and sustainable development needs. This paper discusses the renewable and carbon market linkages and assesses mitigation potential of power sector renewable energy technologies under global environmental intervention scenarios for GHG emissions reduction. An overall energy system framework is used for assessing the future role of renewable energy in the power sector under baseline and different mitigation scenarios over a time frame of 35 years, between 2000 to 2035. The methodology uses an integrated bottom-up modelling framework. Looking into past performance trends and likely future developments, analysis results are compared with officially set targets for renewable energy. The paper also assesses the CDM investment potential for power sector renewables. It outlines specific policy interventions for overcoming the barriers and enhancing deployment of renewables for the future.     

Towards a sustainable hydrogen economy: A multi-criteria sustainability appraisal of competing hydrogen futures

The ‘hydrogen economy’ has the potential to provide a sustainable and secure energy system, and there is a wide and growing literature promoting and exploring different possible hydrogen futures. However, despite broad agreement that hydrogen could make a significant contribution to energy policy goals, the literature exhibits strong disagreements about the form that a future hydrogen economy should take. Visions of the future select, combine and reconfigure individual hydrogen generation, storage, transport and end-use technologies into more or less mutually compatible energy and transportation systems, which embody deeply contested and conflicting views of sustainability.

This paper describes the application of a novel foresight methodology, which combined participatory scenario development, using a backcasting approach, with an expert-stakeholder multi-criteria mapping (MCM) process, in order to provide an integrated, transparent assessment of the environmental, social and economic sustainability of six possible future hydrogen energy systems for the UK. The findings suggest that: hydrogen has the potential to deliver substantial sustainability benefits over the status quo, or, business as usual, futures, but that hydrogen is not automatically a sustainable option; carbon emissions are the single most important dimension of sustainability, but that issues other than carbon and cost need to be considered if hydrogen is truly to deliver greater sustainability. Furthermore, there was significant disagreement about which visions were considered more or less sustainable. These findings reflect two important sources of divergence in the final sustainability rankings: uncertainties and contested views of sustainability.     

Building a sustainable organizational energy evaluation system in the Asia Pacific

In the face of climate change and with the vision for the future of humanity represented by the Sustainability Development Goals, sustainability has become associated with the major and rapid transformation of global systems and the resilience of transformed systems to adapt over time. This dynamic view of transformation has implications for both the design of transformational energy initiatives and their evaluation. As there is an urgent need to evaluate the scale, scope, nature, and sufficiency of transformation toward planetary sustainability, a framework (model) is proposed to determine the most effective energy evaluation capacity building strategies for achieving various individual and group level outcomes, most effective strategies for certain types of participants, and design of different strategies to maximize their impact in a sustainable way. Furthermore, a new energy evaluation organization is identified, which is expected to lead us into this new era.     

Sustainability and future alternatives of biogas-linked agrosystem (BLAS) in China: An emergy synthesis

The biogas-linked agriculture has experienced a rapid development in recent years in rural China, which serves both as part of the country's developmental strategies of cleaner energy and an important reaction to sustainable agriculture call. This paper provides an overview of the economic and environmental performance of biogas-linked agrosystem (BLAS) in China by focusing on efficiency, emission mitigation effect and sustainability. An emergy synthesis combing emergy accounting and emergetic ternary diagram are utilized to evaluate the overall BLAS and its four subsystems (i.e., planting subsystem, breeding subsystem, aquaculture subsystem and biogas subsystem) in terms of current status and future development. Our findings indicate that despite a high energy transformity at system scale and a great dependence on economic input, BLAS advantages itself with high biogas production efficiency and significant emission mitigation effect. Furthermore, the sustainability zone analysis shows that the overall BLAS, planting and aquaculture subsystems maintain medium-term sustainability under all policy scenarios, despite the fact that breeding and biogas subsystems stay in an unsustainable situation due to their relatively severe environmental load. Among all the studied future options, continual biogas construction and effective technological revolution instead of expanding investment in traditional agriculture are preferable routes to further improve the system performance. Last but not least, emissions mitigation, energy efficiency and system sustainability are unveiled to be positively correlated within BLAS, which entitles it a promising energy alternative to enhance biogas energy utilization in the local agriculture in face of today's energy crisis.     

Sustainability assessment of cogeneration sector development in Croatia

The effective and rational energy generation and supply is one of the main presumptions of sustainable development. Combined heat and power production, or co-generation, has clear environmental advantages by increasing energy efficiency and decreasing carbon emissions. However, higher investment cost and more complicated design and maintenance sometimes-present disadvantages from the economical viability point of view. As in the case of most of economies in transition in Central and Eastern Europe, Croatia has a strong but not very efficient co-generation sector, delivering 12% of the final energy consumption. District heating systems in the country's capital Zagreb and in city of Osijek represent the large share of the overall co-generation capacity. Besides district heating, co-generation in industry sector is also relatively well developed. The paper presents an attempt to assess the sustainability of Croatian co-generation sector future development. The sustainability assessment requires multi-criteria assessment of specific scenarios to be taken into consideration. In this respect three scenarios of Croatian co-generation sector future development are taken into consideration and for each of them environmental, social and economic sustainability indicators are defined and calculated. The assessment of complex relationships between environmental, social and economic aspects of the system is based on the multi-criteria decision-making procedure. The sustainability assessment is based on the General Sustainability Index rating for different cases reflecting different criteria and their priority. The method of sustainability assessment is applied to the Croatian co-generation sector contributing to the evaluation of different strategies and definition of a foundation for policy related to the sustainable future cogeneration sector development.     

An analytical method for the measurement of energy system sustainability in urban areas

Assessing the sustainability of urban energy systems and forecasting their development are important topics that have been the focus of recent research. In this paper, an approach for the measurement the sustainability of an urban energy system is introduced. The approach is based on prediction of the future energy needs within the consuming sectors of a city by specification of energy system development scenarios and validation of the scenarios by a multi-criteria decision method. Prediction of energy needs for the area of the city using the simulation model, model for analysis of the energy demands (MAED) is done. Finish the last level of aggregation, using the method of multi-criteria analysis, is getting the General Index of Sustainability (GIS), which shows a measure of the validity or viability, or quality of the investigated scenarios. In this way, the mathematical and graphical made a synthesis of all the indicators that are relevant to sustainable development. The accuracy in determining the mean of the GIS is checked by calculating the standard deviation. Also, a measure of reliability of the preference when watching a few consecutive scenarios was performed. The defined scenarios take into account the utilization of different energy sources, the exploitation of existing energy plants and infrastructure, and the building of new plants. The sustainability criteria are described by a unique set of economic, social and ecological indicators. The new approach was used to forecast the development of sustainable energy system in Belgrade, Serbia.     

区域级综合能源系统多能耦合优化研究

综合能源系统是未来能源消费方式的重要发展方向,按照不同能源品味的高低进行综合互补利用,以取得最合理的能源利用效果和经济环保效益显得至关重要。从功能模块、子系统、区域级综合能源系统三个层级进行模型构建,在合理配置多种功能模块的基础上进行各子系统和综合能源系统的能量平衡计算,建立能耗目标、经济目标、环保目标三种单一目标以及由此任意组合得到的多目标评价指标,制定多能耦合优化策略,实现综合能源系统设计中的方案配置优化。     

Renewable energy for sustainable electrical energy system in India

Present trends of electrical energy supply and demand are not sustainable because of the huge gap between demand and supply in foreseeable future in India. The path towards sustainability is exploitation of energy conservation and aggressive use of renewable energy systems. Potential of renewable energy technologies that can be effectively harnessed would depend on future technology developments and breakthrough in cost reduction. This requires adequate policy guidelines and interventions in the Indian power sector. Detailed MARKAL simulations, for power sector in India, show that full exploitation of energy conservation potential and an aggressive implementation of renewable energy technologies lead to sustainable development. Coal and other fossil fuel (gas and oil) allocations stagnated after the year 2015 and remain constant up to 2040. After the year 2040, the requirement for coal and gas goes down and carbon emissions decrease steeply. By the year 2045, 25% electrical energy can be supplied by renewable energy and the CO₂ emissions can be reduced by 72% as compared to the base case scenario.     

Going beyond energy intensity to understand the energy metabolism of nations: The case of Argentina

The link between energy consumption and economic growth has been widely studied in the economic literature. Understanding this relationship is important from both an environmental and a socio-economic point of view, as energy consumption is crucial to economic activity and human environmental impact. This relevance is even higher for developing countries, since energy consumption per unit of output varies through the phases of development, increasing from an agricultural stage to an industrial one and then decreasing for certain service based economies.In the Argentinean case, the relevance of energy consumption to economic development seems to be particularly important. While energy intensity seems to exhibit a U-Shaped curve from 1990 to 2003 decreasing slightly after that year, total energy consumption increases along the period of analysis. Why does this happen? How can we relate this result with the sustainability debate? All these questions are very important due to Argentinean hydrocarbons dependence and due to the recent reduction in oil and natural gas reserves, which can lead to a lack of security of supply.In this paper we study Argentinean energy consumption pattern for the period 1990–2007, to discuss current and future energy and economic sustainability. To this purpose, we developed a conventional analysis, studying energy intensity, and a non conventional analysis, using the Multi-Scale Integrated Analysis of Societal and Ecosystem Metabolism (MuSIASEM) accounting methodology. Both methodologies show that the development process followed by Argentina has not been good enough to assure sustainability in the long term. Instead of improving energy use, energy intensity has increased. The current composition of its energy mix, and the recent economic crisis in Argentina, as well as its development path, are some of the possible explanations.     

A new perspective in optimum sizing of hybrid renewable energy systems: Consideration of component performance degradation issue

The ever increasing demand for energy and the concerns on the environmental sustainability issue all around the world lead to more interest in alternative sources for energy production. However, as the current costs of the alternative sources such as solar, wind energy conversion systems etc. are relatively higher as compared to the conventional means of energy production, an optimum sizing approach is quite necessary in order to avoid over-sizing of such systems without lowering the reliability of load demand supply in all possible conditions including the variability of meteorological conditions or the changing power demand of load. There are many research papers available in the literature dealing with this optimum sizing issue. Even the mentioned papers significantly contribute to the wider penetration of such sources, none of them consider the power output degradation of alternative energy sources due to aging during their pre-defined operating life time. Besides, there are a few studies utilizing detailed dynamic models of energy sources apart from first-degree linear equations based models that may fall short in presenting the exact dynamics of the related system. Thus, an “observe and focus” algorithm based optimization of a hybrid alternative energy system considering the power output degradation and detailed models of each hybrid system component is performed in this study. Related details presented within the paper can provide a new perspective in optimum sizing of such hybrid systems and may further be considered in future updates of famous sizing software programs commercially or freely available in websites of several laboratories or universities.     

Sustainability improvement in combined electricity and freshwater generation systems via biomass: A comparative emergy analysis and multi-objective optimization

For energy systems, sustainability is a major concern that must be carefully considered when designed and established. Emergy analysis is an effective technique to scrutinize the sustainability of these systems. On the other hand, water shortage is seen to become a big problem in the close future; however, this problem can be effectively alleviated by combined electricity/water production plants, where waste heat is recovered to generate freshwater. This study applies emergy analysis to evaluate and improve the sustainability, renewability, environmental impacts, and economic aspect of such a plant, in which a multi-stage desalination (MSF) system is employed to recover the waste heat from a gas turbine (GT). The plant is fueled by biomass/natural gas (system I), natural gas (system II), and biomass (system III), and the above-mentioned features are compared for the different fuel types. To estimate chemical equilibrium state inside the gasifier, Lagrange's method of undetermined multipliers is applied. Also, considering exergy efficiency and emergy sustainability index as objective functions, biomass/natural gas-fueled system is optimized by adopting a multi-objective optimization approach based on the non-dominated sorting genetic algorithm II (NSGA II). To predict the optimized points' behavior, the Pareto optimal frontier of the system is utilized. The results reveal that using biomass as inlet fuel remarkably improves the sustainability index and reduces environmental impacts. The optimization results show that as sustainability index increases, exergy efficiency decreases. Also, the two optimized points of the system are found to have exergy efficiencies of 20.14% and 25.09% and sustainability indices of 24.67% and 13.60%.     

Key strategies of hydrogen energy systems for sustainability

Here we conduct a parametric study to investigate the effects of hydrogen energy utilization on the global stability and sustainability. In this regard, in order to derive the hydrogen energy based sustainability ratio, the green energy based sustainability ratio, as developed earlier, is modified to come up with a new parameter, namely “hydrogen energy utilization ratio through non-fossil fuels”. We take actual historical data from key sources to determine the role of hydrogen energy for sustainability and make some future projections as the road map for hydrogen economy. In addition, an illustrative example on the hydrogen energy based sustainability ratio is presented by considering green energy sources such as solar, wind, hydro and nuclear to make hydrogen economy more environmentally benign and sustainable. It is found that hydrogen energy based global stability and sustainability ratios increase with the rise of hydrogen energy utilization ratio. The best results for hydrogen energy based sustainability ratio are obtained for the highest hydrogen energy impact ratios between 73.33% and 100%. In case of 10% of hydrogen energy utilization ratio, hydrogen based sustainability ratios for year 2010 are, respectively, determined to be 0.21%, 0.23%, 0.25%, 0.27% and 0.29% in 2.92% of hydrogen based global stability ratio by depending on the hydrogen energy impact ratios (=73.33%$=73.33\%$, 80%, 86.67%, 93.33% and 100%). In case of 20% of hydrogen energy utilization ratio, the hydrogen energy based sustainability ratios are found to be 1.09%, 1.19%, 1.28%, 1.38% and 1.48% in 7.41%, respectively. The results are really encouraging in a way that hydrogen economy appears to be one of the most significant players for better sustainability.     

Energy conservation policy and environment for a clean and sustainable energy future

One of the most serious difficulties facing humanity is the need for a sustainable future. Maintaining nonrenewable energy resources for future generations is a main purpose of sustainability. However, for sustainable future, produced and consumed energy should support human development all social, economic and environmental dimensions. Problems related with environment and energy shortages have put all circles to the task of actively promoting education in energy conservation. Therefore, many countries have started to identify their responsibility for decreasing the unfavorable effect of high energy use on the environment. The primary contribution of this paper will be to ensure energy conservation policy advices to decrease climate change without effecting economic growth for a clean and sustainable energy future.     

Shaping a sustainable energy future for India: Management challenges

Most of the studies on the Indian energy sector focus on the possible future scenarios of Indian energy system development without considering the management dimension to the problem—how to ensure a smooth transition to reach the desired future state. The purpose of this paper is to highlight some sector management concerns to a sustainable energy future in the country. The paper follows a deductive approach and reviews the present status and possible future energy outlooks from the existing literature. This is followed by a strategy outline to achieve long-term energy sustainability. Management challenges on the way to such a sustainable future are finally presented. The paper finds that the aspiration of becoming an economic powerhouse and the need to eradicate poverty will necessarily mean an increase in energy consumption unless a decoupling of energy and GDP growth is achieved. Consequently, the energy future of the country is eminently unsustainable. A strategy focussing on demand reduction, enhanced access, use of local resources and better management practices is proposed here. However, a sustainable path faces a number of challenges from the management and policy perspectives.     

Generating renewable energy from oil palm biomass in Malaysia: The Feed-in Tariff policy framework

The renewable energy (RE) industry in Malaysia began in 2001 in the context of the growing concern about future depletion of conventional fuels and the global environmental concerns about greenhouse gas emissions. The Small Renewable Energy Programme (SREP) is a tool that was first designed to drive the development of the industry based on the abundance of oil palm biomass reserves and other identified renewable energy resources. Due to the slow uptake of this scheme, a new system, the Feed-in Tariff (FiT) was introduced in 2011 to stimulate the industry. By considering the deficiencies of the previous scheme, this paper examines the sustainability of the FiT policy framework in steering the future expansion of small-scale biomass renewable energy businesses in Malaysia. Resulting from the evaluation of the current policy settings and a market based appraisal, this work outlines strategies for enhancing the scheme and suggests future studies aimed at improving the flaws in the present system.     

Governing low-carbon energy transitions in sustainable ways: Potential synergies and conflicts between climate and environmental policy objectives

Climate change is a central sustainability concern, but is often treated separately from other policy areas in environmental governance. In this article we study how low-carbon energy transitions might be governed in line with broader sustainability goals. We identify conflicts and synergies between low-carbon strategies and the attainment of longer-term environmental objectives by examining the Swedish environmental quality objectives as a governance arrangement. Our analysis indicates that low-carbon strategies might be compatible with preserving other aspects of ecological sustainability. However, this requires relevant flanking policies and measures for non-climate objectives, e.g. systems that control the expansion of biomass and ensure the use of sustainable methods. For such a governance system to be credible and capable, it needs to be flexible in terms of adapting to specific and changing contexts, and reflexive enough to factor in new knowledge on requirements for sustainable development and potentially changing values of future generations.     

Harmonising methodological choices in life cycle assessment of hydrogen: A focus on acidification and renewable hydrogen

The environmental sustainability of hydrogen energy systems is often evaluated through Life Cycle Assessment (LCA). In particular, environmental suitability is usually determined by comparing the life-cycle indicators calculated for a specific hydrogen energy system with those of a reference system (e.g., conventional hydrogen from steam methane reforming, SMR-H₂). In this respect, harmonisation protocols for comparative LCA of hydrogen energy systems have recently been developed in order to avoid misleading conclusions in terms of carbon footprints and cumulative energy demand. This article expands the scope of these harmonisation initiatives by addressing a new life-cycle indicator: acidification. A robust protocol for harmonising the acidification potential of hydrogen energy systems is developed and applied to both SMR-H₂ and a sample of case studies of renewable hydrogen. According to the results, unlike other energy systems, there is no correlation between acidification and carbon footprint in the case of hydrogen energy systems, which prevents the estimation of harmonised acidification results from available harmonised carbon footprints. Nevertheless, an initial library of harmonised life-cycle indicators of renewable hydrogen is now made available.