In an age of rapid technological advancement, the increasing need for energy and its related services to satisfy economic and social development has become a critical concern of national governments worldwide. This has triggered researchers to work on metrics for tracking and tracing energy sustainability in order to provide monitoring mechanisms for policy makers. In this regard, multicriteria decision-making (MCDM) methods are becoming more popular to deal with the multidimensional and complex nature of sustainability. We have proposed an extended and revised version of the grey relational analysis (GRA) method, which is integrated with the fuzzy analytic hierarchy process (AHP), to develop a new composite index for comparing the overall energy sustainability performances of 35 OECD member countries. Our case study revealed the performances of selected countries by providing their strengths and weaknesses based on determined criteria as well as the level of change in performances with different criteria weights. The proposed GRA model can be used in different applications of sustainability due to its flexible nature, which provides benefits from goal-oriented extensions in order to adequately capture different aspects of sustainability.

Sustainable development becomes more and more important in recent years, since bold actions are necessary to ensure the needs of future generations. Using renewable sources for producing energy plays an important role to achieve sustainable development. Major global issues like depletion of sources and environmental concerns triggers the rapid development of these clean energy production systems. This paper focuses on the current status and future potentials of different renewable energy sources by considering various quantitative and qualitative factors that may affect the capabilities and significance of renewable energy systems such as the potential for power generation, availability issues, carbon dioxide emissions, capital costs, land requirements and social impacts. Furthermore, some of those factors are used for making comparisons between different technologies and systems, which are also discussed in the paper. The results and discussions reveal that these systems provide promising opportunities for people to access cheap, reliable and clean energy in the future, which is one of the key elements to sustain healthy ecosystems and human life. The recommendations and conclusions presented here will be beneficial to engineers, researchers, city planners and energy policy makers.

Sustainable cities become more popular in recent years, due to increasing amount of people who demand to live in communities which are environmentally, socially and economically resilient. Especially, in a world, where natural sources are at the edge of depletion and the threat of greenhouse gas emissions becomes undeniable, setting sustainability goals for communities plays a vital role. Providing cheap, accessible, clean and reliable energy for the inhabitants of cities by using renewable sources is the key to create sustainable communities. This paper focuses on roof-top integrated photovoltaic systems which are installed and operated by end-users to meet the needs of power in cities. A case study is conducted in Istanbul to make financial assessments in order to find out whether it is worth for investing such technologies. The results and discussions reveal that despite environmental benefits, the payback period of such systems is too high for an investor, which leads to the fact that additional incentives must be provided by the Turkish government. ÖzÇevresel, sosyal ve ekonomik açıdan esnekliği olan topluluklar içinde yaşamak isteyen nüfus gün geçtikçe artmakta ve bu sebeple sürdürülebilir şehirler son zamanlarda daha popüler olmaktadır. Özellikle, doğal kaynakların tükenme sınırında olduğu ve sera gazı salınımının inkâr edilemez bir tehdit haline dönüştüğü yerlerde, topluluklar için sürdürülebilirlik hedefleri oluşturulması hayati