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The paper presents some aspects concerning the production and storage of hydrogen as a power resource. The concept of using hydrogen as a renewable energy source in order to balance the power supply system has to be explained to the students who study Power Engineering at the University of Petrosani as it is an issue of great interest nowadays. Hydrogen generation and storage were studied in laboratory classes with the help of the Renewable Energy Education Set - Horizon, Fuel Cell Technologies. The educational kit can be used to experiment the production of hydrogen with an electrolyzer module supplied by a photovoltaic panel. Using a fuel cell to generate electricity, we powered a LED module, a small fan or a module with a small wheel engine. So, students can see the stages of producing hydrogen and further, electricity. [ABSTRACT FROM AUTHOR]

Abstract: Nowadays renewable sources are being used as clean sources to generate electricity and to reduce the dependency on fossil fuels. The uses of renewable sources are being increased in electricity generation and contributed to reduce the greenhouse gas emission. The function of any electrical power system is to connect everyone sufficiently, clean electric power anywhere and anytime of the country. This can be achieved through a modern power system by integrating electrical energy from clean renewable sources into the nation''s electric grid to enhance reliability, efficiency and security of the power system. The paper on the status of review the driving force of the generation of renewable energy and proposing electrical energy generation from renewable sources to be ensured at least 20% of total energy of Australia. This paper has been studied the existing electricity generation capacity of Australia from renewable and non-renewable sources. Optimal electricity generation from renewable sources has been examined. The environmental impact of electricity generation from renewable sources has been considered. Under this paper the yearly average wind data of past 20 years and above for some meteorological stations of Australia have been used. The prospective electricity generation from wind turbines and solar photovoltaic panels has been proposed in the paper that will increase electrical energy of the power grid of Australia. It was estimated the capital cost of prospective electricity generation farms from wind and solar PV sources. [Copyright &y& Elsevier]

Abstract: This paper presents a power production system for the isolated insular power system of the islands Karpathos and Kasos. Karpathos and Kasos are two small islands, located in the South-East Aegean Sea (Dodecanese complex) that are not connected to the main power distribution network. Energy production is based exclusively on an autonomous thermal power plant and a small wind park, installed on the island of Karpathos. The maximum annual power demand has been estimated to exceed 12MW by 2014. The mean specific annual energy production cost from the existing system has been calculated at 0.249€/kWh in 2008. The proposed system aims at the maximisation of wind energy penetration and the minimisation of imported fossil fuel use for the production of electricity. The proposed system consists of a wind park and a pumped storage system (PSS). The introduced power system aims to guarantee power production for certain hours per day. A thorough sitting of the system is accomplished. Three different sites for the PSS installation are examined before the optimum is selected. The available wind potential of the islands was evaluated using a wind mast installed within the frame of the examined project’s feasibility study. The annual mean wind velocity at the wind park’s installation site was measured to be higher than 11.5m/s. The introduced system’s set-up, and operation & maintenance cost parameters have been estimated. The dimensioning of the system aims mainly at optimising the project’s economic indexes, following the existing legislative framework. The annual guaranteed energy production has also been maximised. An economic sensitivity analysis is performed. It is estimated that the proposed project can exhibit attractive economic indexes, regardless of the availability of a subsidy, on the condition that the selling price of energy should be configured at 0.3552€/kWh and the selling price of guaranteed power should be 127€/kWyear. Under the above mentioned prerequisites, the project payback period is estimated at 5–6years. The present paper proves the economic feasibility of small scale wind powered pumped storage systems, not taking into account the undoubted environmental benefits. [Copyright &y& Elsevier]

Abstract: This paper presents a review of reliability models and methods for estimating renewable energy resources influence on electrical generation availability. These models and methods may be used to evaluate the impacts on the distribution systems reliability of distributed generation integration, especially when they are based on renewable energy sources. For such, the paper presents the main characteristics of renewable resources models that have been developed for wind, small hydro, solar and biomass, and presents the main methods for reliability evaluation of distribution systems with such resources integrated. These evaluation methods may be based on analytical techniques, Monte Carlo simulation or hybrid approaches. The impact of distributed generation on the reliability of electric distribution systems depends mainly on the operational mode and the energy source in which it is based. The most uncertain case is related to generation based on renewable energy of intermittent nature where the generation availability depends on the availability of the energy source and the availability of the generating unit. [Copyright &y& Elsevier]

Abstract: During 2010 and 2011, China had been the largest producer of wind turbines in the world for two consecutive years. How China can transform from being the largest producer to being the strongest producer of wind turbines is currently a great concern in the industry. The purpose of this paper is to discuss this issue from the perspective of the international competitiveness of China''s wind turbine manufacturing industry. Firstly, the paper establishes a model for evaluating the international competitiveness of wind turbine manufacturing industry, which consists of five first-level indexes and 10 second-level indexes. Then, the paper uses these indexes to evaluate the international competitiveness of six leading wind turbine companies in the world—Vestas (Denmark), Gamesa (Germany), GE Wind (the USA), Nordex (Spain), Suzlon (India) and Sinovel (China). The result shows that the international competitiveness of the Chinese wind turbine company, Sinovel, ranked the fifth, lagging behind Vestas, Gamesa, GE Wind and Suzlon. Finally, the paper makes in-depth analysis on the major factors that hamper the international competitiveness of China''s wind turbine manufacturing industry and provides implications for future development of the industry. [Copyright &y& Elsevier]

Solar ponds have been widely utilised in providing low grade heat needed for industrial processes and for heating applications <100 °C. In this paper, a small scale passive electric power generation unit was devised for generating electricity from the heat available in the solar pond. The power generation unit proposed operates without the use of a pump and involves no moving parts. The design of the power generation unit was finalised after performing a comprehensive theoretical study on the possible geometrical arrangements. The power generation unit was fabricated and tested experimentally. The power generation unit consists of 120 commercially available thermoelectric cells accommodated in the outer and inner layers of this dual layer power generation unit. The power generation unit had produced a maximum power of 40.8 W under the condition of T h = 99 °C. Under the normal operation of solar pond, the lower convective zone will have a temperature that lies within in the range of 40 °C –80 °C. Thus, maximum output in the range of 19.5 W–27.4 W is more realistic for the system proposed with the heat to electric conversion efficiency ranges between 0.37%–0.68%. [ABSTRACT FROM AUTHOR]

Power system networks are the largest and most complex systems ever devised by human being. The networks are associated with huge amount of investments where the success of the sector heavily depends on appropriate planning and management. Spatial analysis technologies play very important role in planning, monitoring, and managing of the network by comprehensively considering social, environmental, and economic issues. Spatial analysis, the heart of geographic information systems (GIS) provide an integrated platform for proper management and planning of power systems. The major role of GIS technology includes: (i) developing spatial model for power generating stations, transmission networks, and distribution substations; (ii) determining suitable locations for power generation and distribution stations, and optimal routing of transmission networks; and (iii) integrating renewable energy resources with the planning and management system. Parallel to GIS, global positioning systems (GPS) has introduced new dimensions in spatial research because of its increasing availability with reduced price. The integration of GPS in data measurement techniques made a paradigm shift in (i) monitoring of the power system network with time synchronized data and (ii) finding fault locations as well as taking corrective actions with better accuracy. This paper investigates the evolutionary role of GIS and GPS technologies in different components of power system networks. These technologies are expected to provide a smart and promising platform for integrating virtually all the relevant information and systems required to develop and maintain a sustainable power system networks at local, national, regional, and global levels. [ABSTRACT FROM AUTHOR]

Biogas is one of the most promising renewable energy fuel sources obtained from various organic matters and used for energy requirements. This work is focused on the usage of biogas in power production. The main aim of this study was to evaluate the different factors that affect the power production during anaerobic digestion. This study examines the usage of Organic Fraction Municipal Solid Waste (OF-MSW), wastewater sludge, and co-digestion of both OF-MSW and wastewater sludge for power production. The digestions are performed under mesophilic conditions at an optimum temperature of 36°C. The maximum power produced is 128 kW when using OF-MSW alone and 48.9 kW for co-digestion (50% OF-MSW + 50% wastewater sludge) and 35.5 kW for wastewater sludge. The paper also focuses on various factors such as pH, temperature, and nitrogen concentration and its influence on power production. [ABSTRACT FROM PUBLISHER]

As numerous generation side assets, such as the generating units and the plant equipments, in the Smart Grid system have already aged, well planned maintenance and operational scheduling is needed to maintain their expected longevity. Forced outages and short-notice/temporary maintenance of thermal units should also be considered as likely events. Backup energy sources are required to replace the generating units during the maintenance period. Using conventional storage devices for this purpose is feasible, but costly. Electric vehicles and plug-in hybrid electric vehicles, with vehicle-to-grid capability, referred to as “gridable vehicles”, are a useful choice as storage devices for the same. Second life batteries, disassembled from gridable vehicles after passing their automotive life, are another candidate for this purpose from the economic perspective. A system model that aggregates gridable vehicles and second life batteries together in an intelligent way to provide such backup energy can reduce significant storage costs. Such a system model is presented in this paper for a Smart Grid environment. Our simulation results suggest that using gridable vehicles and second life batteries together can save up to 70% of conventional storage energy costs and recover capital costs for the second life batteries in only 1.5 years. [ABSTRACT FROM AUTHOR]

Stabilization at concentrations consistent with keeping global warming below 2 °C above the pre-industrial level will require drastic cuts in Greenhouse Gas (GHG) emissions during the first half of the century; net negative emissions approaching 2100 are required in the vast majority of current emission scenarios. For negative emissions, the focus has been on bioenergy with carbon capture and storage (BECCS), where carbon-neutral bioenergy would be combined with additional carbon capture thus yielding emissions lower than zero. Different BECCS technologies are considered around the world and one option that deserves special attention applies CCS to ethanol production. It is currently possible to eliminate 27.7 million tonnes (Mt) of CO 2 emissions per year through capture and storage of CO 2 released during fermentation, which is part of sugar cane-based ethanol production in Brazil. Thus, BECCS could reduce the country’s emissions from energy production by roughly 5%. Such emissions are additional to those due to the substitution of biomass-based electricity for fossil-fueled power plants. This paper assesses the potential and cost effectiveness of negative emissions in the joint production system of ethanol and electricity based on sugar cane, bagasse, and other residues in Brazil. An important benefit is that CO 2 can be captured twice along the proposed BECCS supply chain (once during fermentation and once during electricity generation). This study only considers BECCS from fermentation because capturing such CO 2 is straightforward, thus potentially representing a cost-effective mitigation option for Brazil compared to other alternatives. The assessment shows that fuel prices would increase by less than 3.5% due to the adoption of BECCS from fermentation, while increasing investors’ revenues are sufficient to compensate for the investment required. With appropriate government subsidies, or by sharing BECCS costs between all car fuels and all electricity supplied by hydro and bioelectricity, the increment in ethanol and electricity prices could be less than 1% for the final consumer. Meanwhile it would supply 77.3% of all cars’ fuel (private cars) and 17.9% of all electricity in Brazil. [ABSTRACT FROM AUTHOR]

Micro polygeneration utilizing renewable energy is a suitable approach to reduce energy consumption and carbon emission by offering high-efficiency performance, offsetting the need for centrally-generated grid electricity and avoiding transmission/distribution losses associated with it. This paper investigates the energy and environmental potential of a renewable trigeneration system in a residential application under Incheon (Korea) and Ottawa (Canada) weather conditions. The trigeneration system consists of a ground-to-air heat exchanger (GAHX), photovoltaic thermal (PVT) panels and an air-to-water heat pump (AWHP). The study is performed by simulations in TRNSYS (Version 17.02) environment. The performance of the trigeneration system is compared to a reference conventional system that utilizes a boiler for space and domestic hot water heating and a chiller for space cooling. Simulation results showed substantial annual primary energy savings from the renewable trigeneration system in comparison to the reference system--45% for Incheon and 42% for Ottawa. The CO2eq emission reduction from the renewable trigeneration system is also significant, standing at 43% for Incheon and 82% for Ottawa. Furthermore, trigeneration systems' capability to generate electricity and thermal energy at the point of use is considered as an attractive option for inclusion in the future smart energy network applications. [ABSTRACT FROM AUTHOR]

The work reported here addresses load matching improvement in Net Zero Energy Buildings (Net-ZEBs). The related relevant literature shows that currently research work is mainly focused on improving the load matching of individual buildings. In this paper the concept of a Cooperative Net Zero Energy Community (CNet-ZEC) is introduced, extending discussion to the enhancement of load matching at a wider community level. Both building and community levels are compared in order to assess the work proposed here, through the analysis of three distinct scenarios where five Net-ZEBs work individually or in community. The results presented here were obtained through a detailed simulation based on 1-min resolution stochastic load profiles and recorded weather data. The results indicate that over the period of a year the CNet-ZEC has the potential to increase the electrical demand covered by onsite electricity generation up to 21% and the on-site generation that is used by the building up to 15%. The following elements are considered by the CNet-ZEC in order to produce those results: (i) demand heterogeneity of the buildings integrating the community; (ii) the higher number of controllable devices; and (iii) the potential higher amount of energy available to satisfy the community demand. [ABSTRACT FROM AUTHOR]

Biomass from agricultural residues, especially lignocellulosic biomass, is not only seen as a sustainable biomass source for the production of electricity, but increasingly as a resource for the production of biogas and second generation biofuel in developing countries. Based on empirical research in an irrigated rice-growing area, Office du Niger, in Mali, this article builds scenarios for the sustainable potential of rice straw. The paper concludes that there is great uncertainty regarding the size of the sustainable resources of rice straw available for energy, but that the most likely scenario estimates a resource of about 120,000 t, which would permit up to three 5 MW el rice straw-fuelled power plants. Based on the findings from the empirical studies, the article further suggests that recently published research on the potential of rice straw in a number of African countries seems first to underestimate the uncertainty of resource assessments, and secondly to overestimate the resources available for energy production, mainly due to optimistic residue-to-product ratios and availability factors. [ABSTRACT FROM AUTHOR]

Policies to assure combatting climate change and realising energy security have stimulated a rapid growth in global installed capacity of renewable energy generation. The expansion of power generation from renewables, though, has so far lagged behind the growth in generation capacity. This indicates missed and relatively cheap opportunities to reduce GHG emissions. This paper sheds light on the mismatch between installed capacity and power generation for the case of wind power. It analyses and compares wind power developments in the four countries that contributed most to the increase in wind power capacity during the last decade: namely, China, the United States, Germany and Spain. We estimate the dynamics of capacity utilisation of wind power installations and identify its drivers. Finally, we identify potential policies to reduce the gap between power capacity and generation, which will contribute to cost-effective reduction of GHG emissions. [ABSTRACT FROM AUTHOR]

Abstract: Electricity generation from renewable sources of energy will be a key part in the development of future strategies for many countries globally. This renewable electricity generation will be hugely important for Ireland, due to its lack of fossil fuel resources. The extremely good wind resource available provides Ireland with the opportunity of generating vast amount of electricity from wind energy. Large-scale wind electricity generation reached 1264 MW installed capacity by January 2010 in Ireland. However, micro scale wind electricity generation has not been very popular in Ireland to-date. The unclear economics of micro wind turbines, under Irish conditions, is considered the biggest obstacle for expanding micro wind turbine installation in Ireland. This paper presents a methodology to accurately evaluate the economic viability of a micro wind turbine on a case-by-case basis. The methodology utilises the software programmes HOMER and Microsoft Excel 2007 for the energy and economic analyses. This paper also presents a realistic economic analysis of a number of micro wind turbines available in Ireland. [Copyright &y& Elsevier]

Abstract: Power production from renewable energy resources is increasing day by day. In the case of Spain, in 2009 it represented 26.9% of installed power and 20.1% of energy production. Wind energy makes the most important contribution to this production. Wind generators are greatly affected by the restrictive operating rules of electricity markets because, as wind is naturally variable, wind generators may have serious difficulties in submitting accurate generation schedules on a day-ahead basis, and in complying with scheduled obligations. Weather forecast systems have errors in their predictions depending on wind speed. Therefore, if wind energy becomes an important actor in the energy production system, these fluctuations could compromise grid stability. In the previous paper in this brief series , the authors showed technical results of the proposed solution, which consists of combining wind energy production with a biomass gasification system and a hydrogen generation system based on these two sources. In the present paper it is shown the economic results of the study, considering the most profitable technical configurations and three possible economic scenarios. [Copyright &y& Elsevier]

Abstract: Despite possessing a very large potential of renewable energy sources, Australia has lagged behind other developed countries in embracing renewable energy. Various programs and policies have been devised and implemented by Australian governments. Nevertheless, the proportion of renewable energy in electricity generation in Australia has not increased significantly. This paper seeks to explain why Australia has difficulties in adopting renewable energy by using the Political Aspect of Innovation (PAI) framework to examine the causes and barriers that have blocked the taking up of renewable energy. The PAI framework is concerned specifically with public innovation policy in Australia and the way it aims to encourage and support investment in new technology development. The paper finally outlines some future suggestions for charting the progression of the Australian energy system toward a transformative sustainable future. [Copyright &y& Elsevier]

Abstract: This paper attempts to review and discuss the status and future prospects of renewable energy in Oman. Renewable energy sources like solar, wind, hydro, geothermal, and biomass have been revised. The electricity shortages and the challenges to overcome the increase in electrical demands for the near future have been discussed. The investigations found that solar, shore-wind and geothermal could play an important role in the future of renewable energy in country. Also, it is found that there is need to investigate the potential of offshore-wind, biomass, and hydro (tide, wave and ocean thermal energy). The appearance and weight of renewable energy in the higher education programs and the Oman commitment toward renewable energy have been discussed. The paper finishes with some conclusions and recommendations. [Copyright &y& Elsevier]

Abstract: Due to the vast growth of development in the infrastructure and investment in energy, the electricity consumption in the GCC countries had increased at a fast rate; 12.4% from 2005 to 2009 (3.15%, annually). This rate is much larger than the world average, which is 2.2% for the same period, or USA (0.5%). In 2005, the average Watt per person in the GCC countries was 1149 which is much higher than the world average (297W per person) or the European Union (700W/person) – but less than USA (1460W/person). The GCC countries need to increase its electrical capacity by 60,000MW, which represents 80% of the current installed capacity, to meet demand in 2015. This means that there is a need to build 50 more gas fired power generator plant turbine (each rated 1400MW). The GCC countries have realized that depending on gas will not be the solution due to shortage of resource or environmental impact, particularly the GHG emissions. Therefore, they thought back of using renewable energy resources – after lifting it over in 1990s. They also thought of diversity in electricity production where nuclear energy comes to the picture. The power capacity in GCC countries is at around 75,000MW, a projected 9.5% growth in annual demand will require more electricity and energy projects; expected to invest USD 200 billion to 250 billion in between 14 and 20 energy projects by 2020. The paper lists the major renewable energy projects (mainly solar and wind) in each of the six GCC countries. The total capacity of these projects exceeds 600MW. Among these projects is the establishment of the first zero emission house (Green house) in the middle east (7kW solar, wind and fuel cell) constructed in Bapco residence town (Awali) in Bahrain and therefore, been highlighted more in this paper. Moreover, nearly all GCC countries are planning to construct PV plants with large capacity. Also, several projects in Building Integrated Photovoltaic and Building Integrated Wind Turbines are established in GCC countries. The projects made in the GCC countries allow researchers and investors to size the cost of kWh from thermal, PV and wind energy more precisely. For example, it was found that the cost of kWh from large grid connected solar thermal plant (20MW) – with cost of USD 72.5 million and energy – is US ¢ 12/kWh (assuming a life time of 40 years and a discount rate of 4%) while, the cost issue of kWh from PV Electricity (in the GCC countries) is ranging from US ¢ 27 (for ground mount) to US ¢ 35 (for roof mount) as it was deduced from two actually installed project PV in UAE – a GCC country member. Meanwhile, the cost of 1kWh from wind electricity in the GCC countries may be from US ¢10 (large turbine ≈2MW at 80m height with good wind speed) to US ¢ 15 (for large turbine ≈2MW at 80m height with modest wind speed) while the cost of kWh from grid connected Wind farm plant (20MW) – with a cost of USD 38.6 million and energy – is US ¢ 6.7/kWh to US ¢ 8.8/kWh, depending on the location of wind farm. This makes it very challengeable for investor, government (Feed-in-Tariff) and citizens because each citizen in GCC countries pays only (US cent 1 for each kWh, for consumption less than 3000kWh, or even nothing for citizens-like in Qatar). [Copyright &y& Elsevier]

Abstract: This paper is concerned with modeling possible future paths for Lebanon’s electricity future and evaluating them. The baseline scenario (BS) reflects the business-as-usual state of affairs and thus describes the most likely evolution of the power sector in the absence of any climate change-related or other policies. Two alternative scenarios are examined in contrast to the BS; the renewable energy scenario (RES) and the natural gas scenario (NGS). Using the Long range Energy Alternatives Planning System (LEAP) software we conduct a full-fledged scenario analysis and examine the technical, economic, and environmental implications of all scenarios. From an economic standpoint as well as from an environmental perspective both alternative scenarios are superior to the baseline. Hence, the results of the simulation show that the alternative scenarios are more environmentally and economically attractive than the BS. They would help Lebanon meet its social, environmental, and economic development goals, while at the same time providing other unquantifiable benefits that are discussed further in the paper. Anticipated barriers to the shift in energy mix from conventional sources to renewable energy sources are also presented and discussed [Copyright &y& Elsevier]

Abstract: CO2 emissions of the electricity supply sector in China account for about half of the total volume in the country. Thus, reducing CO2 emissions in China’s electricity supply sector will contribute significantly to the efforts of greenhouse gas (GHG) control in the country and the rest of the world. This paper introduces the development status of renewable energy and other main CO2 mitigation options in power generation in China and makes a preliminary prediction of the development of renewable energy in the country for future decades. Besides, based on the situation in China, the paper undertakes a comprehensive analysis of CO2 mitigation costs, mitigation potential, and fossil energy conversation capacity of renewable energy and other mitigation options, through which the influence of renewable energy on the mitigation strategy of China is analyzed. [ABSTRACT FROM AUTHOR]

One biomass energy source is rice husk, which is a very promising renewable energy source as it is an indigenous, cheap, and clean source of energy. However, environmental and financial profiles of electricity generation from rice husk must be assessed to ensure reduction in greenhouse gas (GHG) emission and positive cash flow. GHG emission from a rice husk generating system is significantly less than that from fossil fuel power plants. A dual-fuel diesel engine-generator of 800 kW, using a rice husk gasifier, is considered for this analysis. This paper presents a comprehensive analysis of a traditional energy technology in a new perspective. The results of simulation data analysed in terms of pollution through GHG emissions, financial aspects, and suitability of the scheme for underdeveloped villages in economically developing nations are critical contributions of the paper. It also indicates the expected energy generation from the rice husk available in the region. [ABSTRACT FROM AUTHOR]

Abstract: Portugal is a country with an energy system highly dependent on oil and gas imports. Imports of oil and gas accounted for 85% of the country’s requirements in 2005 and 86% in 2006. Meanwhile, the share of renewable energy sources (RES) in the total primary energy consumption was only 14% in 2006. When focusing only on electricity production, the situation is somewhat better. The share of RES in gross electricity production varies between 20% and 35% and is dependent on the hydropower production in wet and dry years. This paper presents, on a national scale, Portugal’s energy system planning and technical solutions for achieving 100% RES electricity production. Planning was based on hourly energy balance and use of H2RES software. The H2RES model provides the ability to integrate various types of storages into energy systems in order to increase penetration of the intermittent renewable energy sources or to achieve a 100% renewable island, region or country. The paper also represents a stepping-stone for studies offering wider possibilities in matching and satisfying electricity supply in Portugal with potential renewable energy sources. Special attention has been given to intermittent sources such as wind, solar and ocean waves that can be coupled to appropriate energy storage systems charged with surplus amounts of produced electricity. The storage systems also decrease installed power requirements for generating units. Consequently, these storages will assist in avoiding unnecessary rejection of renewable potential and reaching a sufficient security of energy supply. [ABSTRACT FROM AUTHOR]

Abstract: This paper contributes a critical view of the development of grid-connected photovoltaic systems (GCPVS) in Spain during the period 1998–2008 by looking into the different actions that were intended to promote this technology. The Spanish photovoltaic (PV) sector has undergone bullish development in the recent years, but its underlying factors still lack systematic identification and analysis. Accordingly, this paper collects and presents detailed data for describing this evolution. It also makes a special case of the particular promotion of PV systems on roof and goes further to analyze how these actions have affected GCPVS evolution as well as the magnitude of their impact on its performance. The exponential growth of installed cumulative PV power at the end of this period, which largely exceeded the target set for 2008, is canvassed by building an analogy with feedback control systems. In this approach, market response or the PV power attained is considered as the system output, while the different regulation changes are regarded as control actions aimed at enabling GCPVS to hit the energy target. Such an analysis allows determining the most significant delays and control actions that explain the system''s performance. Hence, this study suggests an alternative framework to support the formulation and assessment of energy policy as it puts the emphasis not only on the evolution of the system per se but rather on the performance of the system against the energy target. In this regard, it might contribute to enhance the promotion mechanisms of green technologies. [Copyright &y& Elsevier]

A significant amount of global electric power generation is produced from the combustion of fossil fuels. Steam boilers are one of the most important components for steam and electricity production. The objective of this paper is to establish a theoretical framework for the sustainability analysis of a utility boiler. These analyses can be used by decision-makers to diagnose and optimize the sustainability of a utility boiler. Seven utility boiler systems are analyzed using energy and embodied solar energy (emergy) principles in order to evaluate their environmental efficiencies. They include a subcritical coal fired boiler, a supercritical coal fired boiler, an oil fired boiler, a natural gas fired boiler, a concentrating solar power boiler utilizing a tower configuration, a biomass boiler, and a refuse derived fuel boiler. Their relative environmental impacts were compared. The results show that the natural gas boiler has significantly lower CO 2 emission than an equivalent coal or oil fired boiler. The refuse derived fuel boiler has about the same CO 2 emissions as the natural gas boiler. The emergy sustainability index of a utility boiler system is determined as the measure of its sustainability from an environmental perspective. Our analyses results indicate that the natural gas boiler has a relatively high emergy sustainability index compared to other fossil fuel boilers. Converting existing coal boilers to natural gas boilers is a feasible option to achieve better sustainability. The results also show that the biomass boiler has the best emergy sustainability index and it will remain a means to utilize the renewable energy within the Rankine steam cycle. Before solar boiler technology can be widely used in the United States’ utility power industry, its capital cost and the O&M cost should be reduced. Using the results of this research, decision-makers can make better-informed, environmentally-efficient selections of future utility scale boilers. [ABSTRACT FROM AUTHOR]

Anaerobic digestion of renewable feedstocks has been known as a prospective technology for the production of clean energy in the form of biogas. Biogas is a sustainable energy carrier which is mainly composed of methane (60%) and carbon dioxide (35–40%). Among the raw substances, organic matters obtained from farm animal waste are pivotal sources for biogas production. In recent years, the number of animal husbandry has drastically grown in Malaysia. Accordingly, a large amount of animal waste including manure, blood and rumen content are produced which provide a tremendous source of biogas generation. This paper presents biogas potential from the organic waste obtained from the farm animals and slaughterhouses in Malaysia. The findings of this study indicated that biogas potential of 4589.49 million m 3 year − 1 could be produced from animal waste in Malaysia in 2012 which could provide an electricity generation of 8.27×10 9 kWh year −1 . [ABSTRACT FROM AUTHOR]

This paper presents the development stages of a micro-scale system for electricity generation from biomass with 500 W of power. The proposed system is based on an open steam power cycle, whose conception was aimed at seeking solutions to meet the needs for energy supply in isolated communities in the Amazon region. In addition the great biomass potential in the region is an opportunity for the application of biomass energy to increase the economic activity and develop new technologies. The tests performed demonstrate that the steam turbine is the critical component to the commercial-scale feasibility of the presented technology, particularly when it's proposed manufacturing of the system by small regional industries. [ABSTRACT FROM AUTHOR]

In the recent years, small scale power generation has been recognized as a suitable option for energy access in isolated rural areas due to uneconomical grid extension. A techno-economic feasibility study on the development of an Integrated Renewable Energy System (IRES) is carried out in the paper in order to meet the electrical and cooking energy demands of cluster of village hamlets of Chamoli district of Uttarakhand state (India). An attempt has been made to estimate the potential of locally available renewable energy resources and demands of the study area. The selection of small wind turbine model for the site specified is performed among the various models available in market. Further, nine different combinations of renewable energy resources have been investigated by considering economic, technical and social aspect criteria. Finally, a sensitivity analysis has also been carried out in order to determine the most sensitive parameter of the system. [ABSTRACT FROM AUTHOR]

Hydropower is the backbone of the Brazilian electricity generation sector. Even though the use of this resource is advantaged in terms of greenhouse gas emissions, last years׳ severe droughts have exposed the country׳s huge dependency on hydroelectricity. Brazil׳s electricity supply system has shown to be vulnerable to electricity shortages and has demanded significant overhaul in order to address its challenges. The present paper provides a comprehensive review of the current status of the Brazilian electricity sector and discusses diversification of electricity generation mix as a strategy to improve electricity supply security in the country. An overview of the main features of the energy sources applied in Brazil is also presented through a review of the latest available generation data. The central section of this work is a discussion of the main causes of the current crisis and the future role of renewable energy sources in a 10-year perspective. [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]

Colombia enacted its first legal framework for promoting alternative energies in 2001 and a second framework in 2014. Since the generation technology mix has not changed since 2000, there is a need to understand how regulation and market structure affect the adoption of technologies. In this paper we address the question of what has been the impact of the capacity mechanisms adopted during the 2000s on technology choices for power generation in Colombia. Our approach is to analyze the evolution of market structure and regulation. We found that regulatory uncertainty and low prices drove a surge of small hydro plants during the 2000s. During the 2010s, the new regulatory focus on reliability of supply has resulted in increased coal-fueled generation and large hydro. This increased reliance on hydro power can further delay the entry of renewable technologies and the diversification of the Colombian portfolio. [ABSTRACT FROM AUTHOR]

This paper presents a new active/reactive power closed-loop control system for a hybrid renewable energy generation system used for single-phase residential/commercial applications. The proposed active/reactive control method includes a hybrid estimator, which is able to quickly and accurately estimate the active/reactive power values. The proposed control system enables the hybrid renewable energy generation system to be able to perform real-time grid interconnection services such as active voltage regulation, active power control, and fault ride-through. Simulation and experimental results demonstrate the superior performance of the proposed closed-loop control system. [ABSTRACT FROM PUBLISHER]

This paper proposes an adaptive control algorithm for grid-interfacing inverters in renewable energy-based distributed generation systems. The proposed control algorithm functions in two different modes: basic power generation mode, harmonics compensation mode. In basic power generation mode, the inverter pumps desired amounts of active and reactive powers into the grid at the point of common coupling. In harmonics compensation mode, the control algorithm ensures sinusoidal grid current through load current harmonics mitigation in addition to desired power generation. Moreover, the proposed control algorithm does not use any detection methods for compensation of harmonic currents. Hence, it results in low computational burden. Based on the requirements, the proposed control algorithm can be operated in either of the modes. A proportional–integral controller-based closed loop control is employed for accurate control of the power injected into the grid. A frequency adaptive notch filter is used to synchronize the grid-interfacing inverter with the fundamental component of grid voltage without using any phase locked loop. The effectiveness of the proposed control algorithm in reference active and reactive powers generation, current harmonics compensation is demonstrated successfully by simulation and experimental results. [ABSTRACT FROM AUTHOR]

This paper gives an overview of renewable energy production as impacted by external factors such as environmental concerns, regulations, sustainability, technology innovation etc., and internal factors such as employees׳ talent, performance stability, operations, processes etc., and provides a framework to address these influences. It first gives an overview of the various factors that have been studied in the literature, including externally and internally influenced factors. Although practitioners have analyzed external factors in various topics, both external and internal factors have not been validated in a quantitatively. The purpose of this study is to validate the highly influenced factors which impact the renewable energy business. We describe how a framework model can be used in the production process to address these factors. We conclude with an analysis of the results with findings and recommendations for managing both internal and external factors during operation by using the Supply-Chain Operation Reference Model. [ABSTRACT FROM AUTHOR]

In this paper we study development patterns of Latvian electricity market. It is done based on a newly developed computer-aided simulation model. System dynamics approach was used to simulate long-term development of electricity sector in the region under the existing policy design. Results demonstrate that renewable energy sources have a high potential to integrate in the electricity generation balance. Important preconditions for this to happen are: presence of appropriate support measures, a continuous technological progress and fossil fuel price increase. Under such scenario around 70% carbon dioxide emission savings can be achieved by 2050. [ABSTRACT FROM AUTHOR]

The activation of demand response (DR) potentials offered by electricity consumer flexibility is one promising option for providing balancing power and energy in supply systems with high share of variable renewable energy (VRE) power generation. In this paper, a model-based assessment of the economic DR potential in Germany is presented. It relies on the extension of the REMix energy system model by flexible electric loads. In a case study considering a future German power supply system with a VRE share of 70%, possible cost reductions achieved by investment in DR are quantified. The sensitivity of the results to changes in the assumed DR costs and characteristics are analyzed in additional simulations. The results show that the major benefit of employing DR is its ability to substitute peak power generation capacity, whereas the impact on the integration of VRE power generation is lower. This implies that the focus of DR is on the provision of power, not energy. Even at rather pessimistic cost DR assumptions, more than 5 GW of power plant capacity can be substituted. Consumer flexibility furthermore triggers an increase in the operation of back-up power plants, whereas it decreases the utilization of pumped storage hydro stations. In the model results, the reductions in annual power supply costs achieved by DR add up to several hundreds of millions of Euros. [ABSTRACT FROM AUTHOR]

The European Union is targeting a 20% share of energy from renewable resources by 2020, and this increase is in turn expected to lead to operational challenges that will require various congestion management actions by system operators. In this paper, we deal with topology control of the transmission network as a congestion management resource and evaluate the impacts of topology control on the European electricity network. To do this, we co-optimize unit commitment and transmission switching over 24 h, and we use a decomposition scheme to tackle the resulting large-scale problem. Our analysis is conducted on different scenarios of load and renewable power generation. We find that topology control results in significant cost savings within Europe which tend to be inversely related to net load. The robustness of our results is supported by an extensive sensitivity analysis. [ABSTRACT FROM AUTHOR]

In the last decade a high amount of photovoltaic and wind power generators have been connected to the electric grid, introducing operational problems for transmission and distribution system operators due to the variability and the non-programmability of solar radiation and wind. The paper concerns an analysis on the benefits in adopting storage systems to reduce the imbalance costs associated to renewable energy sources. An analysis on a photovoltaic system has been performed considering different battery technologies. Discrete-time Markov chains have been used to generate a 20 years' time series of irradiance, that has been used to calculate the PV power production. Markov simulation parameters have been deeply studied in order to optimize them and obtain reliable synthetic data of ground irradiance. This data was then used as input of a hybrid PV and storage model allowing to obtain realistic economic and technical results, improving thus the results respect to the methods based on probabilistic weather simulations. An imbalance tariff has been assumed and its cost has been analysed in relation to the storage system costs. An optimal size for the different battery technology has been investigated considering the reduction of variability of the photovoltaic production and the economic convenience of the hybrid system. The use of Markov chains for the optimization of the battery size can be considered as the major novelty of the proposed approach. [ABSTRACT FROM AUTHOR]

Wind-generated electricity is a growing renewable energy resource. Because wind results from the uneven heating (and resulting pressure gradients) of the Earth, future wind resources may be affected by anticipated climate change. Many studies have used global and regional climate models to predict trends in the future wind resource over the continental United States. While some of these studies identified regions that are expected to gain wind energy, their results often come with a high degree of uncertainty, and lack of agreement across different climate models. In this paper we focus on wind energy density as a measure of the available wind resource over the continental United States. We estimate the change in wind energy density from the period 1968–2000 to the period 2038–2070 by using output from four regional climate models from the North American Regional Climate Change Assessment Program (NARCCAP). We find strong agreement across all 4 models that the wind energy resource is expected to increase in parts of Kansas, Oklahoma, and northern Texas – a region already in possession of both large scale generating capacity and political support for wind energy. [ABSTRACT FROM AUTHOR]

This paper investigates the impacts of California, USA reaching its renewable electricity target of 33%, excluding large hydro, by 2020, which is set out in the state's RPS (Renewable Portfolio Standard). The emerging renewable electricity mix in California and surrounding states which form the WECC (Western Electricity Coordination Council) is analysed using the CEPA (Carbon Emission Pinch Analysis) and EROI (Energy Return on Energy Invested) methodologies. The reduction in emissions with increased renewables is illustrated and the challenge of maintaining high EROI levels for renewable generation is examined for low and high electricity demand growth. Results demonstrate that wind and solar PV collectively form an integral part of California reaching the 33% renewables target by 2020. Government interventions of tax rebates and subsidies, net electricity metering and a four tiered electricity price have accelerated the uptake of electricity generation from wind and solar PV. Residential uptake of solar PV is also reducing overall California electricity grid demand. Emphasis on new renewable generation is stimulating development of affordable wind and solar technology in California which has the added benefit of enhancing social sustainability through improved employment opportunities at a variety of technical levels. [ABSTRACT FROM AUTHOR]

Jordan is a country faced with several environmental and energy related issues. It is the Worlds' fourth most water deprived country with a water consumption of only 145 m 3 per capita annually, less than a third of the established severe water poverty line. Jordan is also a country rich in wind and solar potential but practically no utilization with 99% of the produced electricity coming from imported fossil fuels resulting in high CO 2 emissions and a potential security of supply issue. The utilization of reverse osmosis desalination in a combination with brine operated pump storage units and wind and (PV) photovoltaic plants can tackle both issues. The desalination plants can produce the much needed water and act as a flexible demand to increase the penetration of intermittent renewables supported by the brine operated pump storage units. This paper presents six scenarios for the development of the Jordanian energy system until the year 2050. The results have shown that the demonstrated configuration can increase the share of intermittent renewables in the production of electricity up to 76% resulting in a high reduction of fuel consumption, CO 2 emissions and costs. These analyses have been performed using the EnergyPLAN advanced energy system analyses tool. [ABSTRACT FROM AUTHOR]

Insular electricity grids are considered to have a more fragile structure than the mainland ones due to several factors such as the lower inertia because of lower number of generation facilities connected to the system, absence or insufficient interconnection with the main grid, etc. The recent trend of integrating large portions of environmentally sustainable power generation units that have a significantly volatile nature in the generation mix (such as wind and solar energy conversion systems) within this fragile structure, poses profound challenges that need deeper and specific analysis. This study aims to provide an overview of insular power system structures and operational requirements, especially under increasing penetration of renewable energy sources. Firstly, a general evaluation of insular power systems is presented. Then, potential challenges are thoroughly discussed together with opportunities to tackle them. Future technological developments, as well as innovative applications are also given special attention. Hence, this paper contributes to the scarce literature regarding insular power systems by providing a critical overview of issues regarding their operation and possible solutions. [ABSTRACT FROM AUTHOR]

Osmotic power generation is one of the cleaner and sustainable methods for energy generation. This paper presents a study on the optimal size and design of pressure retarded osmosis (PRO) power plant as a viable source of renewable energy in the selected site in Bahmanshir river of Iran. The optimal sizing and design problem is formulated as a Non-Linear Programming (NLP) optimization problem and solved using the standard optimization software titled generalized algebraic modeling system (GAMS). The objective function is minimizing the total cost while considering the technical and economic constraints. Optimization results show that the optimal capacity of the PRO osmotic power plant is 77.8 MW. Economic analysis is performed for the obtained results and it was observed that construction of this type of power plants will not be attractive for private sector investors with the market energy prices (i.e. 8 cents/kW h).The effect of the future development in power density of membrane and membrane unit price in economic feasibility of the osmotic power plant is studied. [ABSTRACT FROM AUTHOR]

The Brazilian government aims at universal electricity access. The national rural electrification initiative has provided electricity services to more than 14 million people since 2003, mainly through grid extension. However, the initiative has not been able to reach remote areas in the Amazon, thus requiring a review of conditions for small scale off-grid power generation projects. As a result, new rules established under the national rural electrification program address the design and implementation of off-grid power generation projects with an installed capacity up to 100 kW. The objective of this paper is to explore the effects of the new set of rules on the levelized cost of electricity for different power generation solutions in the Amazon. Our study shows that the new rules may be beneficial to isolated communities, as they reduce the levelized cost of electricity, favor renewable energy technologies and may contribute to reduce CO 2 emissions. In addition, the new rules may help engage new actors to provide rural electrification of the Amazon region. To fully take advantage of the current scheme, action at local level is required to define the most appropriate model for small-scale power generation projects and establish synergies between concessionaires and local energy providers. [ABSTRACT FROM AUTHOR]

Hydropower, large and small, remains by far the most important of the “renewable energy” for electrical power production worldwide, providing 19% of the planet׳s electricity. Small-scale hydro is in most cases “run-of-river”, with no dam or water storage, and is one of the most cost-effective and environmentally benign energy technologies to be considered for rural electrification in less developed countries. For development of such small hydro-power plants, simple and generally applicable procedures and methods for the design are lacking. The interest in small hydro-power resources is increasing but few published guidelines exist for project design. This study aims in providing a general guidance with regards to economical design and practical realization of the main components of small hydro-power plants and their interactions. There is abundant literature which has discussed various models and control techniques used for small hydro-power plants. We envisage that summarizing such literature and coming out with a review paper would greatly help the policy/decision makers and researchers in arriving at effective solutions. [ABSTRACT FROM AUTHOR]

Among novel technologies for producing electricity from renewable resources, a new class of wind energy converters has been conceived under the name of Airborne Wind Energy Systems (AWESs). This new generation of systems employs flying tethered wings or aircraft in order to reach winds blowing at atmosphere layers that are inaccessible by traditional wind turbines. Research on AWESs started in the mid seventies, with a rapid acceleration in the last decade. A number of systems based on radically different concepts have been analyzed and tested. Several prototypes have been developed all over the world and the results from early experiments are becoming available. This paper provides a review of the different technologies that have been conceived to harvest the energy of high-altitude winds, specifically including prototypes developed by universities and companies. A classification of such systems is proposed on the basis of their general layout and architecture. The focus is set on the hardware architecture of systems that have been demonstrated and tested in real scenarios. Promising solutions that are likely to be implemented in the close future are also considered. [ABSTRACT FROM AUTHOR]

There has been an intense debate on the quantification of the employment effects of renewable electricity deployment in the European Union. However, most studies carried out in the past have focused on specific countries and those with a European-wide scope have not provided disaggregated results per country. Furthermore, differences between importing and exporting countries have not been considered. This paper aims to cover those gaps. It presents a novel methodology which integrates the aforementioned considerations in order to calculate the employment effects of renewable energy deployment. The methodology is useful to calculate dynamic employment factors (considering technology learning effects) and the specific capacity (based on trade effects) to which these factors should be applied. It is applied to three renewable energy technologies – photovoltaics, wind on-shore and wind off-shore- in the European Union Member States in the 2008–2012 period. The results using this novel methodology broadly confirm the figures provided in other contributions in the literature. The proposed methodology can be instrumental in assessing the socio-economic effects of policies and investment programmes targeting the deployment of renewable energy technologies. [ABSTRACT FROM AUTHOR]

The key objective of this paper is to analyze the techno-economic feasibility of this alternative for the Brazilian municipalities, classified according to population subgroups, using this parameter as a basis for the calculation of the municipal solid waste generated, the project costs and revenues. Different expenses were taken into consideration, like equipments and installation costs, operation and maintenance costs and the interest rate of the investment. In relation to revenues, they come from of the sale of electricity, the incomes of the recyclable materials, the fees paid by the Brazilian municipalities for the disposal of municipal solid waste in sanitary landfills and incomes by the carbon credits. An analysis of each population subgroup, combining three different economical scenarios was done, with an annual rate of interests of 10.58% for Scenario 1, 7.5% for Scenario 2 and 15% for Scenario 3. The economic feasibility was evaluated using as economic indicators the net present value and the internal rate of return. The net present value was positive for the municipalities with more than 60,714 inhabitants for the Scenario 1, 34,203 for Scenario 2 and 259,845 for Scenario 3. A hypothetic gasification plant is capable to generate 905 kW/ton municipal solid waste for a population of 60,714 inhabitants (Scenario 1), 794 kW/ton municipal solid waste for a population of 34,203 inhabitants (Scenario 2) and 1065 kW/ton municipal solid waste for a population of 259,845 inhabitants (Scenario 3). It is concluded that the economic feasibility increases with the installation of bigger units, showing a positive scale up gains, therefore as higher the capacity of the installation lower the specific costs and higher are the benefits. [ABSTRACT FROM AUTHOR]

This paper examines the opportunities for the renewable resource of wave energy in Australia's National Electricity Market (NEM). Using 9 years of hourly wave resource data and a typical terminator wave energy converter performance curve, hourly electricity generation profiles and normalised annual wave energy capacity factors were calculated in spatially distributed “polygons” of the NEM. A conservative wave farm design with 3.35 wave energy converters per km, and environmental, marine park and general exclusion zone constraints, has been assumed. The polygon spanning western Victoria has the greatest capacity factor of 0.44. Integrating the hourly electricity generation data revealed that polygons in Tasmania can generate the most electricity, equal to 44.4 TWh/yr. Total generation over all NEM polygons was calculated to be 275 TWh/yr. This exceeds Australia's total electricity generation of 255 TWh for the 2011−2012 financial year. Therefore, wave energy could potentially provide sufficient electricity generation to meet demand in the NEM region. [ABSTRACT FROM AUTHOR]