Search

The liberalization of electricity markets and the development of renewable energy sources has led to new challenges for decision makers. These challenges are accompanied by an increasing uncertainty about future electricity price movements. The increasing amount of papers, which aim to model and predict electricity prices for a short period of time provided new opportunities for market participants. However, the electricity price literature seem to be very scarce on the issue of medium- to long-term price forecasting, which is mandatory for investment and political decisions. Our paper closes this gap by introducing a new approach to simulate electricity prices with hourly resolution for several months up to three years. Considering the uncertainty of future events we are able to provide probabilistic forecasts which are able to detect probabilities for price spikes even in the long-run. As market we decided to use the EPEX day-ahead electricity market for Germany and Austria. Our model extends the X-Model which mainly utilizes the sale and purchase curve for electricity day-ahead auctions. By applying our procedure we are able to give probabilities for the due to the EEG practical relevant event of six consecutive hours of negative prices. We find that using the supply and demand curve based model in the long-run yields realistic patterns for the time series of electricity prices and leads to promising results considering common error measures. [ABSTRACT FROM AUTHOR]

This paper presents the editorial for the Renewable and Sustainable Energy Reviews joint special issue devoted to the research work discussed and presented at the 11th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES), held from the 4th September to the 9th September 2016 in Lisbon, Portugal and the 2nd South East European (SEE) SDEWES Conference held from June 15th to June 18th, 2016 in Piran, Slovenia. This special issue is in line with the journal's aim of publishing research from across the ever-broadening field of renewable and sustainable energy with a strong review element. Previous SDEWES conference special issues have gathered a significant knowledge base in the field of sustainable development that reflects the continuous research efforts of the SDEWES research community. Therefore, this editorial provides not only an overview of the papers published in this particular special issue, but also a wider overview of the current trends in the domain of sustainable and renewable energy. This year's special issue focuses particularly on the benefits of the bio-based economy, energy security issues, fossil fuel thermal plant alternatives and environmental constraints, district heating and cooling together with cross sector energy efficiency and energy conservation issues. Sustainable transport systems, the issue of fuel poverty in urban neighbourhoods and renewable energy to support development of peripheral rural areas, optimising passive building design for hot climates and solar-powered heating and cooling are further topics featured in this special issue. In the process of selecting papers for this special issue, the guest editors invited in total 23 extended manuscripts for consideration for publication. After a rigorous review process by expert reviewers overseen by the guest editors a total of 16 articles were accepted for publication. [ABSTRACT FROM AUTHOR]

This paper presents a state of art literature review of slip power recovery scheme (SPRS) as an adjustable speed alternating current (AC) drive with various control methodologies for performance enhancement of electric drives. Starting from the brief history of components of control methodologies for SPRS to various control techniques including inverter control, chopper control, field oriented control, vector control, matrix converter control, microprocessor control, sliding mode control, digital signal processing control, neural network control, fuzzy logic control, and optimal control have been reviewed in this paper. The literature related to harmonic analysis of SPRS and use of SPRS in wind power generation has also been reviewed in this research paper. The paper is focused on providing a comprehensive perspective on the state of art of SPRS to the researchers, manufacturers, industries, and application engineers dealing with adjustable speed SPRS drives. The contributions of various researchers in this area have been presented in a classified manner which will serve the reader as a quick, useful, and ready reference. The issues related to control techniques with emphasis on induction machine drive have been highlighted and rigorously examined in this paper. [ABSTRACT FROM AUTHOR]

Modeling tools for the optimal Hybrid Power Systems (HPS) supply planning and demand management have been relatively established. However, complementary tools that can provide planners, decizion-makers, energy managers and electrical as well as power engineers with graphical and visualization insights that are vital for better conceptual understanding of the problems, particularly at the onset of hybrid power systems planning and design, have just been developed over the last five years. This paper reviews the six-year development of the insight-based graphical and algebraic Process Integration (PI) tools for the optimal HPS supply planning and demand management, i.e., from its inception in the year 2011, until 2016. Known as the Power Pinch Analysis (PoPA), the tool has been among the next-generation PI techniques for resource conservation following the developments of the heat, mass, water, gas, materials, property, solid and carbon emission pinch analysis techniques. This paper discusses the progress, challenges and contributions of PoPA in promoting Renewable Energy (RE) utilization in HPS. Case studies on implementation of PoPA for HPS planning and design presented in the paper show encouraging improvement on HPS profitability and reliability. [ABSTRACT FROM AUTHOR]

Access to electric power supply has always had a significant role in promoting improvements in all the society sectors, nevertheless nowadays 1.3 billion of people still do not have electricity access. Moreover, most of them live in rural areas of developing countries which are often isolated, scattered populated and characterized by poor infrastructure and services. In this situation, the growing consideration towards the target of universal access to energy has emphasized the role of rural electrification, and off-grid small-scale generation represents one of the most appropriate options. As a consequence, the scientific literature has devoted attention to this topic with a large number of papers. In this frame, the present analysis focuses on off-grid systems for rural electrification and provides a general framework to this topic and an analytical review of the literature. The work is based on the review of more than 350 papers mainly published from 2000 to 2014 within selected journals, and it is organized in two sections. In the first one we describe the role of small-scale generation systems throughout the process of electrification, the main features of rural areas and their typical energy uses, and we propose a new comprehensive taxonomy for off-grid systems for rural electrification. In the second one we develop an extensive review of the selected literature according to the proposed classification and to five main research areas: Technology: layout and components; Models and methods for simulation and sizing; Techno-economic feasibility analyses and sustainability analyses; Case studies analyses; Policy analyses. The work results in a comprehensive review which organizes and capitalizes the main fundamentals of the addressed topic and provides elements to get acquainted with the literature. [ABSTRACT FROM AUTHOR]

The present global energy scenario, in which fossil fuels play a preponderant role, faces significant energy and environmental challenges. To help address these challenges, countries across the world are increasing the contribution made by renewable energy (RE) resources to their energy supplies. Feed-in Tariff (FiT) is one of the most effective incentive policies used to promote the RE sector especially at the micro-generation level. The key objective of the FiT schemes is to provide financial support to residential, industrial and commercial consumers to encourage them to become RE producers. Solar photovoltaic (PV) is one of the most promising RE technologies. This paper provides an overview of the solar PV developments in the Association of South East Asian Nation (ASEAN) countries. It reflects upon the RE trends in the world as well as providing an introduction to the ASEAN countries. It reviews the progress of solar PV in each of the ASEAN countries especially in terms of RE policies, growth in terms of PV installations and research and development activities. Finally, the paper presents conclusions and a set of recommendations. Out of the 10 ASEAN countries, 5 have implemented FiT as a key policy incentive to stimulate the progress of RE. It is found that the ASEAN countries have great potential for solar PV in term of their annual solar insolation levels, which ranging from 1460 to 1892 kWh/m 2 per year. [ABSTRACT FROM AUTHOR]

Recently, automotive original equipment manufacturers have focused their efforts on developing greener propulsion solutions in order to meet the societal demand and ecological need for clean transportation, so the development of new energy vehicle (NEV) has become a consensus among governments and automotive enterprises. Efficient electrical energy storage system (EESS) appears to be very promising for meeting the rapidly increased requirements of vehicular applications. It is necessary to understand performances of electrical energy storage technologies. Therefore, this paper reviews the various electrical energy storage technologies and their latest applications in vehicle, such as battery energy storage (BES), superconducting magnetic energy storage (SMES), flywheel energy storage (FES), ultra-capacitor (UC) energy storage (UCES) and hybrid energy storage (HES). The research priorities and difficulties of each electrical energy storage technology are also presented and compared. Afterwards, the key technologies of EESS design for vehicles are presented. In addition, several conventional EESSs for vehicle applications are also analyzed; the comparison on advantages and disadvantages of various conventional EESSs is highlighted. From the rigorous review, it is observed that almost all current conventional EESSs for vehicles cannot meet a high-efficiency of power flow over the full operation range; optimization of EESS and improved control strategies will become an important research topic. Finally, this paper especially focuses on a type of linear engine, a brand new automotive propulsion system used for NEV; the guiding principle of EESS design for the new type of linear engine is proposed, an overview of a novel hybrid EESS based on hybrid power source and series–parallel switchover of UC with high efficiency under wide power flow range for the type of linear engine is presented, and advanced features of the novel hybrid EESS are highlighted. [ABSTRACT FROM AUTHOR]

The number of regional and national power systems with a high share of wind and solar power in the world is quickly increasing. The background for this development is improved technology, decreasing costs, and increased concern regarding environmental problems of competing technologies such as fossil fuels. For the future there are large possibilities for increasing the renewable electricity share. However, variable renewable power production has to be balanced. Demand side flexibility offers an interesting approach to the balancing issues. The aim of this paper is to compare flexibility potentials and how they were estimated in seven Northern European countries in order to compare general challenges and results as well as the connection between used method and results. The total flexibility is estimated to 12–23 GW in a system with a total peak load of 77 GW. [ABSTRACT FROM AUTHOR]

This paper presents a set of policy recommendations for the market design of a future European electricity system characterized by a dominant share of renewable energy supply (RES), in line with the stated targets of European governments. We discuss the market failures that need to be addressed to accommodate RES in liberalized electricity markets, review the evolution of the EU's RES policy mechanisms, and summarize the key market impacts of variable RES to date. We then set out economic principles for wholesale market design and use these to develop our policy recommendations. Our analysis covers the value of interconnection and market integration, electricity storage, the design of RES support mechanisms, distributed generation and network tariffs, the pricing of electricity and flexibility as well as long-term contracting and risk management. [ABSTRACT FROM AUTHOR]

The ever greater share of renewable energy sources (RES) in the European energy market stresses the transmission grid to its limits with rising frequency. Therefore, there is a pressing need for a spatially and temporally detailed model of the European power system to serve as a basis for investigating the efficient integration of RES. Here we outline a far-reaching description of transmission grid operation and present a review of approaches developed for modeling the physical power flows and the respective congestion management techniques that control them. By this, we hope to equip the interdisciplinary energy research community with a better understanding of power systems and corresponding modeling tools, thus enhancing their respective efforts. Additionally, a literature review and classification of existing studies on these topics is included in the paper as well. The analysis shows that the fundamental modeling components determining power flows across power systems include the electricity market, the inter-zonal power trading and the intra-zonal congestion management models, where a complete incorporation of all of them requires an iterative or multi-level approach. However, due to the high complexity of such an approach, most common and computationally efficient strategies apply integrated approaches using linearized descriptions for the physical flows. [ABSTRACT FROM AUTHOR]

This paper presents a self-reconfiguring MPPT to maximize the power extracted from solar photovoltaic panels. The proposed method is based on the reconfiguration of solar photovoltaic panels; it is particularly suitable for real-time recovery of power losses from DC-DC buck-converter during the variation of the resistive load value. The developed algorithm changes the disposition of panels in series and in parallel according to the needs. The simulation results show the reliability of the developed method. [ABSTRACT FROM AUTHOR]

This paper presents planning and optimization of standalone DC microgrids for rural and urban applications in India. Load profiles in the form of a rural village, an urban residential building and a business organisation are considered for the study. Using these load profiles, different microgrid configurations with generation from PV, wind turbine and biodiesel generators are constructed. Optimization studies are then carried out using Homer Energy software to determine the optimal system configuration which has the lowest cost of energy. Historical data of hourly solar irradiation and wind speed were also used in the study to obtain a realistic result. A special case study for the rural scenario with a partial connectivity to the grid is also conducted which is reminiscent to the poor reliability of supply in India. The study also gives a detail comparison between the various cost components, electrical productions, energy management and emissions for each of these systems. The results of optimization show reasonable cost of electricity for reliable supply of power for the various load configurations as compared to the actual grid prices. [ABSTRACT FROM AUTHOR]

Expansion planning models are often used to support investment decisions in the power sector. Towards the massive insertion of renewable energy sources, expansion planning of energy storage systems (SEP – Storage Expansion Planning) is becoming more popular. However, to date, there is no clear overview of the available SEP models in the literature. To shed light on the existing approaches, this review paper presents a broad classification of SEP, which is used to analyze a database of about 90 publications to identify trends and challenges. The trends we found are that while SEP was born more than four decades ago, only in the last five years increasing research efforts were put into the topic. The planning has evolved from adequacy criteria to broader targets, such as direct costs, mitigation of CO 2 emissions, and renewable integration. The modeling of the network, power system, energy storage systems (ESS), and time resolution are becoming more detailed. Uncertainty is often considered and the solution methods are still very diverse. As outstanding challenges, we found that (1) the large diversity of ESS, in contrast to conventional generation technologies, and (2) the complex lifetime and efficiency functions need to be addressed in the models. (3) Only a high temporal and spatial resolution will allow for dimensioning the challenge of integrating renewables and the role of ESS. (4) Although the value of ESS lies beyond shifting energy in time, current SEP is mostly blind to other system services. (5) Today, many flexibility options are available, but they are often assessed separately. In the same line, although cross-sectorial (power, heat, transport, water) SEP is becoming more frequent, there are many open tasks towards an integrated coordination. The planning of future energy systems will be multi-sectorial and multi-objective, consider the multi-services of ESS, and will inherently require interdisciplinary efforts. [ABSTRACT FROM AUTHOR]

People are becoming more and more sensitive to the ecological consequences of global warming and environmental devastation. The objective is to replace the use of fossil fuel energy with renewable forms of energy. In the field of building construction, this leads to a new legislation frameworks and radical changes in how we design our buildings. The use of renewable in the building envelope is much varied and opens many opportunities for creative designers. Many architects have already integrated PV successfully in their buildings. This paper reviews the present day application of BIPV and BIPV-T technologies. In addition to it thermal modeling, energy and exergy analysis of BIPV and BIPVT system are also discussed. This study also reviews the recent developments of the technology worldwide. [ABSTRACT FROM AUTHOR]

Energy consumption for any vehicle is described by energy balance (relationship between “energy in” and “energy out”), which consists of energy produced, energy consumed, internal losses as well as the need to overcome the inertia resistance to motion. Hybrid vehicles show big potential for further reduction in fuel consumption and exhaust gas emissions. Therefore, there is nothing strange in the fact that the hybrid cars are often identified as step on the journey to a more sustainable future. Currently, the powertrain concept allows synchronization of the operation of an ICE and an electric motor and redistribution of mechanical energy flows with the help of transmission shifts depending on the mode of operation of the hybrid powertrain (HPT). Different HPT control algorithms are applied in hybrid vehicle designs, however, the purpose of all of them is to: (i) minimize fuel consumption, (ii) minimize exhaust gas emission, (iii) minimize the system price, and (iv) ensure good vehicle control characteristics. This paper presents the novel algorithms suitable for real-time estimation of economic and ecological characteristics for the hybrid 2WD, 4WD, and High Mobility Multipurpose Wheeled Vehicle (HMMWV) vehicles moving under urban, extra-urban and off-road conditions. [ABSTRACT FROM AUTHOR]

The building stock in the world consumes approximately 40% of the energy and emits one third of the total greenhouse gases emissions (GHG). Improving the energy efficiency in buildings is vital to address the climate change and achieve energy independence (i.e. to become net-zero energy). Improving energy performance in existing buildings has been receiving significant attention recently, which entails reducing energy demand for building operations, without affecting the health and comfort of its occupants. This approach requires strategies beyond mere technical advancements. However, there is limited published literature which has comprehensively addressed these issues. The aim of this paper is to critically review existing body-of-the-knowledge on improving energy efficiency of operating both commercial and institutional buildings. Peer-reviewed journal articles published from year 2000 to 2014 in reputed journals were reviewed. This review investigated contemporary energy efficiency approaches including technical, organizational, and behavioural changes. Based on the comprehensive literature review, a strategy map was developed as a pathway for achieving better building energy performance. It was noted that even though the existing studies predominately focused on technical advancements, approaches such as building behavioural changes have been largely overlooked. Findings of this study provide an important basis for setting up a national and organization wide strategy for improving the energy efficiency of commercial and institutional buildings. [ABSTRACT FROM AUTHOR]

In this paper, a review is made on the various parameters influencing the productivity of the solar stills. The researches on the factors improving productivity such as area of absorption, minimum depth of water, water–glass cover temperature difference, inlet water temperature, heat storage, phase change materials, vacuum technology and other methods such as using reflectors, condensers, multi effect distillation, etc. are discussed here. The review showed that the productivity increases when the area of the absorption is increased. The basin water depth is the main parameter that affects the productivity of the still. The increase of the water–glass cover temperature difference ( T w − T g ) also plays a vital role in increasing the productivity. Preheating the feed water to the still basin shows a considerable improvement in the productivity. The studies showed that solar stills with heat storage medium and phase change materials can produce distillate during off-shine hours (nocturnal distillation) and thereby, enhance the productivity. Maintaining vacuum conditions and the use of reflectors and condensers improves the performance of the solar stills. Various modifications in the solar stills such as weir type stills, multi effect distillation, thermoelectric cooling, inclined type stills, etc. enhanced the productivity of the solar stills. [ABSTRACT FROM AUTHOR]

Given rapid depletion of conventional energy sources and environmental degradation caused by their over exploitation, the renewable energy sources are believed to be the future. Technologies utilizing renewable energy sources differ significantly from one another, not only with regard to technical and economic aspects but also in relation to their reliability, maturity, and operational experience in utility scale conditions. Technologies used to harness solar energy have emerged as the most promising and mature since solar energy is abundant, freely available, and it has commercial potential too. This paper presents a review of advancements made in the field of solar thermal technology with a focus on techniques employed for its performance enhancement. It also covers the description of different types of solar collectors to facilitate the systematic understanding of solar thermal technology and the novel modifications realized in each category of solar collectors have been highlighted to promote the use of solar energy in routine activities. Performance enhancement techniques such as geometrical modifications on the absorber plate, use of solar selective coatings and nanofluids have been given a special attention. [ABSTRACT FROM AUTHOR]