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Abstract: Energy is indispensible in modern society and is one of the most important components of socio-economic development. Nepal is one of the least developed countries with more than 80% of its population residing in rural communities. Per capita energy usage – often viewed as a key index of the development – in the country is far less than the global average per capita energy usage. The energy sector is dominated by the traditional energy sources such as fuel woods, crop residues and animal dung mainly for domestic usage contributing to about 86% of the national energy consumption. Currently 40% of the population has access to electricity, and the rural electrification accounts for only 29%. The majority of rural populations are meeting their energy needs by burning biomass in traditional stoves which has several environmental and public health issues. Nearly all fossil-derived fuels consumed in the country are imported in a refined form, and the perpetual increase in petroleum imports has adversely impacted the existing fragile economy of the country. Despite a huge potential in harnessing various renewable energy resources such as hydropower, solar power, wind energy and biofuels/bioenergy, these resources have not been sustainably captured due to geographical, technical, political and economical reasons. This paper presents a brief account of Nepal''s renewable energy resources and the current status of various renewable energy technologies (RETs) such as micro-hydro, solar power, wind energy, biofuel/bioenergy, improved cook stoves, and improved water mill. It also highlights the opportunities and barriers for the development of RETs. Finally this paper presents some recommendations for the promotion, development and implementation of RETs in the country. [Copyright &y& Elsevier]

Abstract: The most important renewable sources are hydropower, biomass, geothermal, solar and wind. Turkey''s geographical location has several advantages for extensive use of most of these renewable energy sources. In recently, electricity has demand increased significantly; it is the fastest growing end-use of energy. Therefore, technical, economic and environmental benefits of hydroelectric power make it an important contributor to the future world energy mix. In the world, particularly in the developing countries renewable energy resources appear to be one of the most efficient and effective solutions for sustainable energy development in Turkey. Turkey''s geographical location has several advantages for extensive use of most of the renewable energy sources. This paper deals with policies to meet increasing energy and electricity demand for sustainable energy development in Turkey. Turkey has a total gross hydropower potential of 433GWh/year, but only 125GWh/year of the total hydroelectric potential of Turkey can be economically used. [Copyright &y& Elsevier]

[Display omitted] • Detailed assessment of Organic Rankine Cycles is presented. • Mixture working fluids achieves higher thermodynamic efficiency. • Biomass and solar energy are still rarely adopted as ORC's heat resources. • USA and Europe have major share in ORC systems. • Studies for reducing the levelized cost of electricity is needed to be carried out. This paper presents state-of-the-art review on organic Rankine cycle (ORC) by assessing the working fluids, thermal resources, cooling utilities, and commercial status with future aspects. It is found that the mixture working fluids achieve higher thermodynamic efficiency. However, the difficulty in obtaining the optimum composition and components limits their applications. The thermal resources with different temperature ranges and cooling utilities are then assessed to investigate their effects on the thermodynamic performance of ORC. The low-temperature ORC utilizing waste heat and geothermal heat is dominant, while biomass and solar energy are still rarely adopted as ORC's heat resources. From the commercial perspective, the USA and Europe are the leaders in conversion of low-grade waste heat into useful power using ORC. Furthermore, the main challenges of ORC are: (a) selection of appropriate working fluid with suitable expander, and (b) reducing the specific cost of the small-scale ORC system to compete with the renewable energy. Finally, several future research directions are identified such as: (1) overall performance of the ORC system including its thermodynamic efficiency, stability and safety needs to be investigated with experimental studies; (2) a general methodology should be developed for the selection of working fluids; (3) studies for reducing the net present cost and levelized cost of electricity with techno-economic optimization are needed to be carried out. This study benchmarks the recent progress on ORC technology and presents an insight into the scientific problems that need to be explored to nexus low-grade heat to power in the future. [ABSTRACT FROM AUTHOR]