a b s t r a c t Homogeneous acid catalysts received wide acceptability because of their fast reaction rates. However, postproduction costs incurred from aqueous quenching, wastewater and loss of catalysts led to the search for alternatives. Until recently, heterogeneous base catalyzed-biodiesel production also gained the atten- tion of most researchers. This was because the process minimized the problems of homogeneous catalysis in terms of catalyst regeneration and recycling in continuous processes. However, despite these advances, the ultimate aim of producing biodiesel at affordable cost is yet to be realized. Further, the process requires refined feedstocks which account for as high as 88% of the final production costs. Thus, the focus of many research efforts is towards the rational design and development of solid acid catalysts aimed at reduc- ing biodiesel production costs. Therefore, this study reviewed current literature on the activities and advantages of solid acid catalysts used in biodiesel production. It discussed in details how the prepara- tion method and prevailing reaction conditions affect the catalytic activity of the catalyst. The review concluded by suggesting way forward from the traditional trial-and-error method to a rational means of determining catalytic activities.

Activity of solid acid catalysts for biodiesel production: A critical review

Need for renewable energy education and training at all levels is globally recognized. During the last three decades a large number of countries across the globe have initiated academic programmes on renewable energy technologies and related aspects. A review of published literature on renewable energy education initiatives across the globe, challenges faced, and potential approaches towards efficient and effective solutions are presented in the paper.

Renewable energy education: A global status review

A bird's eye view of Ghana's renewable energy sector environment: A Multi-Criteria Decision-Making approach

Socioeconomic and demographic factors that influence publics' awareness on the different forms of renewable energy sources

This paper concerns with the emerging power system stability issues, classification, and research prospects under a high share of renewables and power electronics. The decades-old traditional power system is undergoing a fast transition with two most prominent features: 1) high-penetration of renewable power generators, utilizing intermittent renewable sources such as wind and solar, and 2) high-penetration of power electronic devices in the generation e.g., wind turbine converters and solar power inverters, transmission e.g., flexible ac or dc transmission system converters, and distribution/utilization systems e.g., electric vehicle and microgrid. The development of modern power systems with dual high-penetrations, i.e., high-penetrations of renewables and power electronic devices, influences the power system dynamics significantly and causes new stability issues. This paper first overviews equipment-level features and system-level stability challenges introduced under the dual high-penetration scenario of the modern power system. Next, the impacts of emerging stability challenges on various aspects of the classical stability issues and classifications are highlighted. Under this context, this paper discusses the validity and limitations of the existing classical and extended power system stability classifications proposed by different IEEE/Cigre Working Groups. Furthermore, a new power system stability classification framework is proposed, which not only maintains the inherent logic of the classical classification but also provides wide coverage and future adaptability of the emerging stability issues. Finally, various classification-oriented research prospects in the power system stability domain are highlighted.

Power system stability issues, classifications and research prospects in the context of high-penetration of renewables and power electronics

Challenges of renewable energy penetration on power system flexibility: A survey

The levels of awareness about the renewable energy sources of university students in Turkey

Unlike traditional grid, the smart grid increases the efficient use of available energy with dynamic pricing, real-time control, and self-healing. It is an innovative modern grid structure that enables bi-directional communication of instantaneous data from all parts of the energy generation, transmission, distribution, and end-users. One fundamental component of the smart-grid is the more efficient transmission of electricity. Overhead power lines need to be dynamically monitored and scaled for efficient electrical energy transmission. In this study, we investigated dynamic line rating and its devices for smart grid infrastructure.

Towards to smart grid: Dynamic line rating

The important parts of a transformer, such as the core, windings, and insulation materials, are in the oil-filled tank. It is difficult to detect faults in these materials in a closed area. Dissolved Gas Analysis (DGA)-based fault diagnosis methods predict a fault that may occur in the transformer and take the necessary precautions before the fault grows. Although these fault diagnosis methods have an accuracy of over 95%, their validity is controversial since limited data are used in the studies. The success rates and reliability of fault diagnosis methods in transformers, one of the most important pieces of power systems equipment, should be increased. In this study, a hybrid fault diagnosis system is designed using DGA-based methods and Fuzzy Logic. A mathematical approach and support vector machines (SVMs) were used as decision-making methods in the hybrid fault diagnosis systems. The results of tests performed with 317 real fault data sets relating to transformers showed accuracy of 95.58% using a mathematical approach and 96.23% using SVMs.

/pdf/hybrid-condition-monitoring-system-for-power-transformer-1s6x39bj.pdf

Hybrid Condition Monitoring System for Power Transformer Fault Diagnosis

The increasing consumption of energy and the greenhouse-gas emissions are challenges in the transport and building sectors. Compared to the other transportation types public railway transport systems are the most energy efficient regarding carbon footprint. Modern urban railway public transport systems have the significant advantages of large passenger capacity, punctuality, safety, going green in the urban environment and reducing carbon footprint, is a scientific consensus. However, the energy demand for railways are increasing in proportion to passenger load, require implementing innovative solutions for optimizing the energy consumption and reducing carbon emission. Leadership in Energy and Environmental Design (LEED) is a building rating system used worldwide. The credit categories of the LEED consist of seven different topics from the Energy and Atmosphere to Materials and Resources. In this study, the LEED certification application to railway station and facilities will be discussed mainly energy efficiency criteria.

/pdf/green-building-certification-of-urban-public-railway-sle8pufo2d.pdf

Secil Varbak Nese

Papers

Challenges of renewable energy penetration on power system flexibility: A survey

The levels of awareness about the renewable energy sources of university students in Turkey

Towards to smart grid: Dynamic line rating

Hybrid Condition Monitoring System for Power Transformer Fault Diagnosis

Green building certification of urban public railway transport systems for sustainable cities