Article

The intermittency of wind, solar, and renewable electricity generators: Technical barrier or rhetorical excuse?

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Abstract

A consensus has long existed within the electric utility sector of the United States that renewable electricity generators such as wind and solar are unreliable and intermittent to a degree that they will never be able to contribute significantly to electric utility supply or provide baseload power. This paper asks three interconnected questions: 1. What do energy experts really think about renewables in the United States? 2. To what degree are conventional baseload units reliable? 3. Is intermittency a justifiable reason to reject renewable electricity resources?To provide at least a few answers, the author conducted 62 formal, semi-structured interviews at 45 different institutions including electric utilities, regulatory agencies, interest groups, energy systems manufacturers, nonprofit organizations, energy consulting firms, universities, national laboratories, and state institutions in the United States. In addition, an extensive literature review of government reports, technical briefs, and journal articles was conducted to understand how other countries have dealt with (or failed to deal with) the intermittent nature of renewable resources around the world. It was concluded that the intermittency of renewables can be predicted, managed, and mitigated, and that the current technical barriers are mainly due to the social, political, and practical inertia of the traditional electricity generation system.

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... Thermal energy storage is one of the leading research technologies that could be used to overcome the problem of intermittent loading and continuous energy supply associated with renewable energy. The share of renewable energy sources in power systems is increasing rapidly, but current U.S. grid systems are incapable of accommodating not more than 35% of solar or wind energy [4]. Thermal energy storage technologies could provide flexibility during peak energy demand hours and facilitate renewable energy in the electric grids [5]. ...
... Experimental results show that the highest temperature drops of 17.3, 18.8, 25.4, and 15.7°C occurred for NH 4 Cl, (NH 4 ) 2 CO, NH 4 NO 3 , and NaNO 3 , respectively, as shown in Figure 2. The solubility of salt is important because, with less water, the salt produces a higher cooling effect. The solubilities of NH 4 Cl, NH 4 NO 3 , and NaNO 3 in g of solute per 100 g water at 20°C are 29.7, ...
... During the development of salt mixture, as NH 4 NO 3 has the highest solubility and showed a maximum temperature drop, it was used as the major content. It was noticed that NPK salt mixtures showed better results than individual salts, as shown in Figure 3 and 4 ). Also, less water was needed for generating the cooling effect, and hence, less heat was required to evaporate the water from the salt composition. ...
Article
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Thermal energy storage has a potential future to store renewable energy. Thermochemical energy storage (TCES) is the most promising and possesses more advantages over sensible and latent heat thermal storage systems such as higher energy storage density and ambient temperature storage. The major concern at this time for TCES is to find the material or combination of materials which can be thermally stable, have high energy storage density and be non-toxic. In this paper, Fertilizer based salts as a potential TCES material for cooling applications are studied experimentally. To produce a cooling effect, salts are dissolved in water and a drop in temperature is measured experimentally. Systematic evaluation for the combination of Nitrogen (N), phosphorus (P) and potassium (K) based salts are used to produce the cooling effect. Individuals and 14 various mixtures of NPK salts such as NH4Cl, K2SO4, (NH4)2CO, NH4NO3, KNO3, NaNO3, and NH4H2PO4 have been studied experimentally. The cooling effect in the range of 200-400 kJ per kg of salt is produced when the salt is dissolved in the water. It is observed that an average of 24 °C to 28 °C instant decrease in temperature is noticed when 60-80 g of water is added to the mixture of salt. Among the investigated salt mixture, NPK4 yielded a maximum temperature drop of 30 °C.
... But is this true? Lange (2006), Lange et al. (2006, 2009, Krauss et al. (2006), Holttinen et al. (2006), Milligan, et al. (2009, Intergovernmental Panel on Climate Change (2012 p, 623) and even the North American Electric Reliability Corporation (NERC, 2010, p. 9) all report wind energy forecast-error metrics that are weighted by the capacity of the equipment used to produce the energy. These publications make it appear that wind energy forecasting has resolved the intermittency challenge. ...
... The notion that the challenge of wind energy's intermittency is mythological is increasingly accepted. For example, Sovacool (2009) interviewed 62 individuals affiliated with electric utilities, regulatory agencies, interest groups, energy systems manufacturers, nonprofit organizations, energy consulting firms, universities, national laboratories, and state institutions in the United States. Based on their responses and a review of the literature, Sovacool concluded that "the intermittency of renewables can be predicted, managed, and mitigated, and that the current technical barriers are mainly due to the social, political, and practical inertia of the traditional electricity generation system." ...
Article
The metric representing the wind energy forecast error, when reported as a percent, is calculated quite differently than the error metrics for electricity transmission, electricity load, or in other industries such as manufacturing when they are also reported as a percent. The resulting calculated metric is quite different from what would be reported if the method utilized elsewhere was employed. This paper examines the possible forecast assessment and operational challenges associated with this finding. Concerning the prospects for improvement, the errors reported in MW of energy have a systematic component. With this insight, we developed a model to improve accuracy.
... But is this true? Lange et al. (2006, 2009, Krauss, et al. (2006), Holttinen, et al. (2006, Kariniotakis, et al. (2006), Milligan, et al. (2009), IPCC ( 2012 and even the North American Electric Reliability Corporation (NERC; 2010, p. 9) all report wind energy forecast-error metrics that are weighted by the capacity of the equipment used to produce the energy. These publications make it appear that wind energy forecasting has resolved the intermittency challenge. ...
... The notion that the challenge of wind energy's intermittency is mythological is increasingly accepted. For example, Sovacool (2009) interviewed 62 individuals affiliated with electric utilities, regulatory agencies, interest groups, energy systems manufacturers, nonprofit organizations, energy consulting firms, universities, national laboratories, and state institutions in the United States. Based on their responses and a review of the literature, Sovacool concluded that "the intermittency of renewables can be predicted, managed, and mitigated, and that the current technical barriers are mainly due to the social, political, and practical inertia of the traditional electricity generation system." ...
Preprint
The metric representing the wind energy forecast error, when reported as a percent, is calculated quite differently than the error metrics for electricity transmission, electricity load, or in other industries such as manufacturing when they are also reported as a percent. The resulting calculated metric is quite different from what would be reported if the method utilized elsewhere was employed. This paper examines the possible forecast assessment and operational challenges associated with this finding. Concerning the prospects for improvement, the errors reported in MW of energy have a systematic component. With this insight, we developed a model to improve accuracy.
... A more extensive list of examples can be found in the paper by Brown et al. [17]. In their research, these authors deconstruct and oppose a common claim that variable renewable energy sources (VRES) are unreliable and intermittent to the degree that they are unable to contribute significantly to the electric power supply or to serve baseload power [18,19]. ...
... The importance of energy storage is supported by the fact that accurately forecasting renewables is difficult. For example, even though it is possible to forecast wind power output a day in advance, forecast errors of 20%− 50% are not uncommon [18]. ...
Article
This paper presents a mathematical model for estimating the optimal sizing and assessing a standalone hybrid power system's performance entirely based on variable renewable energy sources and coupled with a hybrid energy storage system. This study evaluates how different levels of the main components' capital cost and the loss of power supply probability would affect the cost of energy and the power system's optimal sizing. The case study selected for this study was Ometepe Island in Nicaragua, where the crater lake of an extinct volcano was considered a feasible upper reservoir of a pumped storage hydropower plant, reducing the investments associated with this component. The mathematical formulation considers energy storage losses and gains, and the Pareto efficient solutions of the multi-objective optimization model simultaneously increase reliability, reduce the cost of energy, and minimize curtailment energy. By employing time-series with an hourly resolution, the model allows assessing the impact of the interannual variability of renewable energy sources on the system's performance. As for the case study, the cost of energy obtained from the model results ranges between €0.047/kWh and €0.095/kWh, based on international reference values, and these values match the information available in the literature and other databases.
... BTESs could make an important contribution in areas where seasonal demands vary substantially [76]. In addition, renewable energy sources such as solar and wind energy are intermittent sources-that is, the energy produced is fluctuating on a daily, weekly, or seasonal basis [77,78]. This causes an imbalance in energy demand and supply. ...
Article
Full-text available
The reduction of CO2 emissions has become a global concern. In this regard, the EU intends to cut CO2 emissions by 55% by 2030 compared to those of 1990. The utilization of shallow geothermal energy (SGE) in EU countries is considered the most effective measure for decarbonizing heating and cooling. SGE systems utilize heat energy collected from the earth’s crust to provide secure, clean, and ubiquitous energy. This paper provides a literature review on the use of SGE for heating and cooling purposes. The latest advances in materials, new innovative structures, and techno-economic optimization approaches have been discussed in detail. Shallow geothermal energy’s potential is first introduced, and the innovative borehole structures to improve performance and reduce installation cost is outlined. This is followed by an extensive survey of different types of conventional and thermally enhanced collectors and grouts. Attention is mainly given to the techno-economic analysis and optimization approaches. In published case studies, the least economic break-even point against fossil fuel-based heating systems occurs within 2.5 to 17 years, depending on the local geological conditions, installation efficiency, energy prices, and subsidy. Ground source heat pumps’ cost-effectiveness could be improved through market maturity, increased efficiency, cheap electricity, and good subsidy programs.
... Con respecto a otras fuentes renovables, la hidráulica presenta una mayor facilidad para organizar su programación en virtud a que se puede hacer una mejor previsión de su disponibilidad. En cambio, las fuentes eólicas y solares fotovoltaicas se encuentran limitadas principalmente por su intermitencia [5]. Como consecuencia, esta An Optimization Model for Operations of Large-scale Hydro Power Plants Gonzalo E. Alvarez L intermitencia obliga a tener una mayor cantidad de sistemas de generación de reserva o de almacenamiento de energía para estas tecnologías [6], [7]. ...
Article
Globally, there is an increase in the proportion of renewable sources for electricity generation. Among renewable sources, hydropower is the most widespread. For this reason, the improvements of their applications have been the focus of researches. Hydroelectric power plants have numerous aspects which might represent several economic advantages, if they are operated efficiently. Mathematical optimization models are interesting tools that help in the decision-making processes. In this context, this paper introduces a new Mixed Integer Lineal Programming model that determines the most convenient combination of units to operate a large-scale hydro power plant. Several aspects of reality are taken into account, which are sometimes not considered, such as the variation of the hydraulic head and the performance of other elements besides the turbines, as floodgates. To prove the effectiveness of the new model, the Itaipú Power Plant is selected as a case study. It has an installed power capacity of 14,000 MW and holds the world record in terms of annual generation with 103 million MWh. Three possible scenarios are evaluated in order to analyze the behavior of this plant in normal and extreme situations. The results indicate that the model effectively reduces computational times, and that power generation is influenced by market price variations and reservoir limitations.
... Generally, the goal of design and control of wind turbines is to improve their efficiency and to enhance their reliability [42], [43]. The major challenge facing the control of the wind turbines is the intermittency of wind energy itself [44]. Naturally, the wind speed varies continuously. ...
Thesis
Full-text available
Wind energy represents one of the major renewable energy sources that can meet future energy demands to sustain our lifestyle. During the last few decades, the installation of wind turbines for power generation has grown rapidly worldwide. Besides utility scale wind farms, distributed wind energy systems contributes to the rise in wind energy penetration. However, the expansion of distributed wind energy systems is faced by major challenges such as the system’s reliability in addition to the environmental impacts. This work is intended to explore various control algorithms to enable the distributed wind energy systems to face the aforementioned challenges. First of all, a stall regulated fixed speed wind turbine augmented with a variable ratio gearbox has been proven to enhance the wind energy capture at a relatively low cost, and considered as an attractive design for small wind energy systems. However, the high reliability advantage of traditional fixed-speed wind turbines can be affected by the integration of the variable ratio gearbox. A portion of this work is intended to develop a control algorithm that extends the variable ratio gearbox service life, thus improves overall system reliability and reduces the expected operational cost. Secondly, a pitch regulated variable speed wind turbines dominates the wind energy industry as it represents a balance between cost and flexibility of operation. They can be used for midsized wind power generation. Optimizing its wind energy capture while maintain high system reliability has been the one of the main focuses of many researchers. Another portion of this work introduces a model predictive control framework that enhances the reliability of pitch regulated variable speed wind turbines, thus improves their operational cost. Finally, one of the major environmental challenges facing the continuous growth of wind energy industry is the noise emitted from wind turbines. The severity of the noise emission problem is more significant for small and medium sized wind turbines installed in the vicinity of residential areas for distributed power generation. Consequently, the last portion of this work is intended to investigate the potential of wind turbine control design to reduce noise emission in different operating conditions with minimal impact on power generation.
... The research on energy harvesting is a promising and emerging field that has been received broad interest within both the academic community and industry [1]. In the past few years, energy generation from ambient mechanical sources has emerged as a promising methodology to inexhaustibly power both large-scale and small-scale electronic device systems [2][3][4].Regarding the scope of small-scale powering, a wide range of technologies require long-term operation, reduced performance losses, low maintenance and performance adaptability to external mechanical excitations [5]. These are emerging technologies aiming to develop high-performance autonomous remote sensors, multifunctional implantable biomedical devices, wearable devices, mobile applications, IoT and communication networks, among many others, in which the self-powering ability is recognized as critical [6][7][8][9][10][11][12]. ...
Article
Full-text available
Motion-driven electromagnetic energy harvesting is a well-suited technological solution to autonomously power a broad range of autonomous devices. Although different harvester configurations and mechanisms have been already proposed to perform effective tuning and broadband harvesting, no methodology has proven to be effective to maximize the harvester performance for unknown and time-varying patterns of mechanical power sources externally exciting the harvesters. This paper provides, for the first time, a radically new concept of energy harvester to maximize the harvested energy for time-varying excitations: the self-adaptive electromagnetic energy harvester. This research work aims to analyze the electric energy harvesting gain when self-adaptive electromagnetic harvesters, using magnetic levitation architectures, are able to autonomously adapt their architecture as variations in the excitation patterns occur. This was accomplished by identifying the optimal harvester length for different excitation patterns and load resistances. Gains related to electric current and power exceeding 100 can be achieved for small-scale harvesters. The paper also describes comprehensive case studies to verify the feasibility of the self-adaptive harvester, considering the energy demand from the adaptive mechanism, namely the sensing, processing and actuation systems. These successful results highlight the potential of this innovative methodology to design highly sophisticated energy harvesters, both for a small- and large-scale power supply.
... However, proposals for unmooring grassroots from the incumbent energy paradigm through mobilization of radical transformational politics encounters critical challenges on two accounts. First, grassroots efforts to actualize a "truly progressive social transformation" (ibid, p. 22) in the energy sector encounter pronounced regime pressures, often buttressed by technocratic and deterministic claims for utility control (Smith et al., 2016;Sovacool, 2009;Stirling, 2008Stirling, , 2014. Second, grassroots communities indicate variable support for radical politics on account of differential socio-cultural and political leanings across different countries (Frantzeskaki, Avelino, & Loorbach, 2013), and in the case of U.S. even across states and localities (Byrne et al., 2007;Outka & Feiock, 2012;Yi & Feiock, 2014). ...
... However, this obstacle can also be resolved by the development of technologies and the expansion of the scale of application. After an investigation of related institutions and an extensive literature review of the intermittency of renewable energy, Sovacool pointed out that the more renewables that are deployed, the more stable the system becomes and the easier it becomes to predict, manage, and mitigate the intermittency of renewables [65]. ...
Article
China is undergoing an energy revolution by pursuing a low-carbon economy and a fundamental change in its energy structure. The plan is for renewable energy to be 50% of China's energy consumption by 2050 and to decrease carbon intensity 60–65% by 2030 from the 2005 level. This energy revolution highlights the importance of renewable energy for energy security and sustainable development in China. The energy revolution reflects the requirement of a low-carbon economy and China's international commitments to combating climate change. However, curtailed renewable energy and expanding fossil energy constitute a paradox in this energy revolution. Although China has progressed in its development of renewable energy, this paradox hinders renewable energy from challenging the dominance of fossil energy in the short term. Notably, an energy revolution can be considered a process of socio-technical transition that requires the co-evolution of social, economic, political, and technical factors. Using the multi-level perspective as an analytical framework, it is uncovered that this paradox results mainly from social and economic obstacles at the macro and meso level, rather than technological factors at the micro level. The energy trilemma, interest divergence, and weak supervision are the main social and economic factors affecting whether the priority of renewable energy can be secured. Limiting the expansion of renewable energy improperly and eliminating traditional fossil energy arbitrarily are two undesirable extremes. Proper mechanisms should be established to accelerate the transition process while acknowledging the inertia and importance of the traditional energy industry. The measures should include the coordination of interests during energy transition, the rule of law in the energy sector, the full life-cycle clean production of renewable energy, and the phasing out of unreasonable fossil fuel subsidies.
... Based on the energy gap enclosure within the actual renewable energy scenario and the fossil fuel diminishment and greenhouse emissions growths, optimal energy management is needed [1]. Along with the issue of fulfilling the energy requirements of actual scenarios, renewable sources must address the intermittency in the generation and distributions of energy from renewable sources, such as in eolic and photovoltaic systems [2]. Currently, through the implementation of energy storage systems such as batteries and electrochemical capacitors, this problem is being addressed. ...
Article
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In this paper, an electrochemical performance evaluation of galvanostatically deposited Co(OH)2 onto few-layered graphene (FLG) is presented. The electrochemical evaluation was carried out in a two-electrode symmetric cell arrangement. Electrodes were synthesized by combining FLG made through simple instrumentation atmospheric pressure-chemical vapor deposition (AP−CVD) process onto Cu foil substrates, and galvanostatically deposited Co by chronopotentiometry deposition. Faradaic contributions of as-deposited Co(OH)2 increase the areal capacity of the electrochemical cells (EC) with an areal capacity of 0.72 µA h cm −2 , in comparison with the FLG EC with an areal capacity of 0.04 µA h cm −2 at 4 mA cm −2. Along with the areal capacity enhancement, specific energy, as the galvanostatic charge/discharge evaluation tells, showed a boost from 0.434 to 7.79 mW h g −1 evaluated at 4 mA cm −2 , when the EC is galvanostatically deposited with Co. In terms of specific power, both EC presents similar values around 335 mW g −1. These results offer some insight into the electrochemical complexation of carbonaceous supports obtained from the bottom-up synthesis approach and how they can be tuned to increase the electrochemical storage capabilities of the materials.
... Common renewable sources for large-scale electric powering, such as wind and sun, are intermittent, which result in complex grid managements and high energy production costs. The latter occurs mainly due to the backup costs to support the fluctuating electrical energy production, such as costs related to conversion processes and energy storage [11][12][13][14][15]. However, current non-intermittent renewable energy systems, including those harvesting electric energy from the ocean, require complex mechanical systems for energy transduction, such as turbines, oleo-hydraulic systems, transmission systems, etc., which bear high maintenance costs and significant performance losses. ...
Article
Motion-driven electromagnetic energy harvesters have the ability to provide low-cost and customizable electric powering. They are a well-suited technological solution to autonomously supply a broad range of high-sophisticated devices. This paper presents a detailed review focused on major breakthroughs in the scope of electromagnetic energy harvesting using magnetic levitation architectures. A rigorous analysis of twenty-one design configurations was made to compare their geometric and constructive parameters, optimization methodologies and energy harvesting performances. This review also explores the most relevant models (analytical, semi-analytical, empirical and finite element method) already developed to make intelligible the physical phenomena of their transduction mechanisms. The most relevant approaches to model each physical phenomenon of these transduction mechanisms are highlighted in this paper. Very good agreements were found between experimental and simulation tests with deviations lower than 15%. Moreover, the external motion excitations and electric energy harvesting outputs were also comprehensively compared and critically discussed. Electric power densities up to 8 mW/cm³ (8 kW/m³) have already been achieved; for resistive loads, the maximum voltage and current were 43.4 V and 150 mA, respectively, for volumes up to 235 cm³. Results highlight the potential of these harvesters to convert mechanical energy into electric energy both for large-scale and small-scale applications. Moreover, this paper proposes future research directions towards efficiency maximization and minimization of energy production costs.
... Wind and solar energy are very useful when used in large quantities in geographically spaced locations. So, the law of averages yields a relatively constant supply (SOVACOOL, 2009). Thus, the problem is not one of variability per se, but how such variability can best be managed, predicted, and mitigated. ...
Article
Wind and solar energy have stood out in recent years because of the growth of global installed capacity. This work aims to present wind and solar photovoltaic energy development and its regulatory framework in Brazil, and demonstrate the potential for centralized hybrid generation. Official studies, research reports, and thematic maps were consulted, and two pilot hybrid plants were studied. Results indicate that there is great potential for centralized hybrid generation in the Brazilian Northeast region. However, there is a need for the regulatory framework to evolve to enable its development.
... For a long time, it's been believed that the intermittency of Renewable Energy Sources (RES) is the main barrier to the massive adoption of greener energy sources, especially solar Photovoltaic (PV). In reality, evidence points towards politics and resistance to change from the traditional energy sector as being the main hindrance [1]. However, depending on the level of penetration, the inherent intermittence of PV energy may lead to several technical issues and inefficient harnessing of this resource [2,3], especially in systems operation, planning and scheduling. ...
Article
Full-text available
With advances in solar energy research and increasingly accurate forecast techniques, intermittency no longer stands as a barrier to the adoption of solar energy. Coupling reliable data and knowledge on the inherent variability of the solar resource with advanced learning and forecast models, renewable energy can take an even bigger role in today’s energy paradigm. The objective of this work is to develop and test a low-cost data acquisition system able to provide relevant data for solar energy forecast models. The results yielded from the performed tests indicate high correlation between image derived attributes and power measurements 20 s ahead.
... The traditional photovoltaic and wind systems require a large installation area and do not generate continuous electric power, due to intermittency (Jithendranath et al., 2021;Liu et al., 2020;Sovacool, 2009;Zhou et al., 2018). In this study, the patented system (Lahlou et al., 2021) combines solar and wind power into a compact self-transforming device that can produce clean electricity and request just a small area of installation. ...
Article
Today, renewable energy and energy efficiency are key to limiting global warming and preventing the dangerous effects of climate change. The biggest problem with conventional solar and wind turbine systems is the intermittency of electrical power generation. Even if these two energy sources can be complementary, the space occupied by these hybrid systems remains very important. This work proposes an improved management algorithm for a patented transformable photovoltaic-wind system, which mainly uses two flexible photovoltaic panels which are automatically deformed by an electromechanical system from the planar shape to the semi-cylindrical shape of the Savonius wind turbine blades. When weather conditions change, this system switches to eco-friendly photovoltaic (PV) or wind turbine (WT) mode, allowing a good total power generation from two solar power sources or wind turbine power. The contribution brought for this work relates to the realization and the improvement of the management algorithm to determine a better change to the mode PV or the mode WT. The operation test was simulated in 8760 hours for the year 2021. This developed algorithm allows several theoretical calculations of the power produced from solar radiation and wind speed data, thereafter the algorithm compare and determines the overall power and selects the optimal PV or WT mode. In this study, the overall power generated by the invented system produces more electricity per hour, the power Pt increases by 75.55% compared to the power Pwt, and also the power Pt increases by 68.15% compared to Pvp power.
... We understand that PV is addressed as a means for simple and limited lighting or charging cell phones and low-level voltage uptake. The intermittent perception of RE electricity generation was also investigated in 2009 by Sovacool [43], although this insight in our study is due to two main reasons: (i) low capacity of solar PV system, which is a consequence of economic limitations (explained in Section 3.1), i.e., adopters of PV have to settle for low capacities (to some 5-10 KW capacity), which in turn affects their perception of its application; (ii) the Gaussian diagram of power vs. time of the output electricity of a PV system. The dependence of a PV system on the solar irradiation during the day, increasing with sunrise, reaching its maximum at noon, and decreasing by sunset, produces the perception of a non-stable source of electricity. ...
Article
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To examine the social acceptance of renewable energy infrastructures regarding their position in the success of energy transition, attitudes towards these technologies have been increasingly recognised to play an important role. Notably, most of empirical literature has focused on the global northern countries, with bottom-up transition governance structure. In this paper, we study attitudes towards photovoltaics in Iran, as a fossil fuel-rich country of the global south, with a top-down energy transition structure and committed to UNFCCC. We focused on governmental organisations as a key stakeholder group regarding their role in winning public acceptance. Aiming at finding determinants of attitudes towards PV, we conducted 15 qualitative interviews in 10 governmental organisations in Golestan, Guilan and Tehran. Taking an inductive approach to the data, we considered the acceptance and attitude theories as sensitising concepts to investigate common and specific issues in terms of social acceptance in Iran. We find accessing electricity and diversifying electricity resources via PV as the key technical drivers, and the upstream policies as the key political drivers towards PV adoption. Though the weak policies (design and implementation), privileging economic and technical obstacles, do hinder the PV adoption and shape negative attitudes toward it. We realise that the previous literature overlooked the fossil fuel-rich countries and their energy transition governance structure. Our findings imply that better-designed upstream policies with a more enabling policy framework are needed to motivate actions on the governmental organisation level.
... To address these issues, the development of novel renewable energy technologies with abundant resources, wide distributions, renewability and environmental friendliness has become the best choice to reduce fossil fuel consumption. And although current research has been focused on new energy technologies based on wind energy, tide energy and solar energy [1], the large-scale application of these new energy technologies is hindered by intrinsic unpredictability and intermittency [2]. Therefore, the search for novel energy carriers that can enable transfer between renewable resources and end-use customers is vital. ...
Article
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Hydrogen is an ideal energy carrier in future applications due to clean byproducts and high efficiency. However, many challenges remain in the application of hydrogen, including hydrogen production, delivery, storage and conversion. In terms of hydrogen storage, two compression modes (mechanical and non-mechanical compressors) are generally used to increase volume density in which mechanical compressors with several classifications including reciprocating piston compressors, hydrogen diaphragm compressors and ionic liquid compressors produce significant noise and vibration and are expensive and inefficient. Alternatively, non-mechanical compressors are faced with issues involving large-volume requirements, slow reaction kinetics and the need for special thermal control systems, all of which limit large-scale development. As a result, modular, safe, inexpensive and efficient methods for hydrogen storage are urgently needed. And because electrochemical hydrogen compressors (EHCs) are modular, highly efficient and possess hydrogen purification functions with no moving parts, they are becoming increasingly prominent. Based on all of this and for the first time, this review will provide an overview of various hydrogen compression technologies and discuss corresponding structures, principles, advantages and limitations. This review will also comprehensively present the recent progress and existing issues of EHCs and future hydrogen compression techniques as well as corresponding containment membranes, catalysts, gas diffusion layers and flow fields. Furthermore, engineering perspectives are discussed to further enhance the performance of EHCs in terms of the thermal management, water management and the testing protocol of EHC stacks. Overall, the deeper understanding of potential relationships between performance and component design in EHCs as presented in this review can guide the future development of anticipated EHCs. Graphic Abstract
... The shift to renewable sources away from current, more traditional fossil fuel-based production comes with some challenges. Current energy generation architecture is resilient when compared to renewable source generation, meaning that they can meet near-constant demand requirements without intermittency [16]. Lack of resiliency forces renewable source energy generation to integrate energy storage capabilities within their grids to provide energy when those renewable sources abate. ...
Conference Paper
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Islanded, renewably powered microgrids require energy storage or emergency generation to overcome intermittency. Batteries and fossil fuel generators have traditionally filled these roles. However, liquid air energy storage (LAES) is a promising alternative. Using power in excess of immediate demand, a LAES system can liquefy and cryogenically store ambient air. When renewable generation abates, the liquid air can be expanded through a turbine to provide power to the microgrid. This study explores energy recovery from a dual Stirling cycle LAES system. Liquid air is generated by a commercial Stirling cryocooler and stored in a vacuum dewar. A second Stirling engine utilizes the temperature difference between the liquid air and surroundings to run a small electric generator. This paper focuses on energy recovery from the cryogenic liquid air through the Stirling engine using a series of experiments. Liquid air volume as a function of time and power for varying loads were measured and used to quantify the energy recovered from the stored liquid air. Energy efficiency is calculated and recommendations for design improvements are presented. Follow-on work will include design and operation of an updated dual-Stirling LAES system. This work is part of a larger effort to determine the feasibility of different energy storage methods for small, mobile applications as well as fixed infrastructure energy storage systems.
... Based on the energy gap enclosure within the actual renewable energy scenario and the fossil fuel diminishment and greenhouse emissions growths, optimal energy management is needed [1]. Along with the issue of fulfilling the energy requirements of actual scenarios, renewable sources must address the intermittency in the generation and distributions of energy from renewable sources, such as in eolic and photovoltaic systems [2]. Currently, through the implementation of energy storage systems such as batteries and electrochemical capacitors, this problem is being addressed. ...
... The authors find there is still a need for specific research on airfoil configuration, i.e. aerodynamic characteristics of conventional and flatback airfoils. Various challenges emerge when using the wind turbine technology, for instance, there is high competition between industries [176], wind measurement devices accuracy [177], maintenance and operational problems [178][179][180][181][182][183], and power/grid distribution challenges [184][185][186]. There are different solutions to improve the control system [187,188] and wind forecasting devices [189][190][191]. ...
Article
Renewable energy technologies are receiving much attention to replacing power plants operated by fossil and nuclear fuels. Of all the renewable technologies, wind power has been successfully implemented in several countries. There are several parameters in the aerodynamic characteristics and design of the horizontal wind turbine. This paper highlights the key sensitive parameters that affect the aerodynamic performance of the horizontal wind turbine, such as environmental conditions, blade shape, airfoil configuration and tip speed ratio. Different turbulence models applied to predict the flow around the horizontal wind turbine using Computational Fluid Dynamics modeling are reviewed. Finally, the challenges and concluding remarks for future research directions in wind turbine design are discussed.
... This is done with an estimated cost compared to the use of different solution technologies and can be introduced comparatively to the environment as a whole. Life Cycle Assessment (LCA) can be used to measure costs integrated with VRE because the installed capacity with future projections is available [41,107,114,125]. This system can significantly improve recommendations on policies issued. ...
Article
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Wind power, solar power and water power are technologies that can be used as the main sources of renewable energy so that the target of decarbonisation in the energy sector can be achieved. However, when compared with conventional power plants, they have a significant difference. The share of renewable energy has made a difference and posed various challenges, especially in the power generation system. The reliability of the power system can achieve the decarbonization target but this objective often collides with several challenges and failures, such that they make achievement of the target very vulnerable, Even so, the challenges and technological solutions are still very rarely discussed in the literature. This study carried out specific investigations on various technological solutions and challenges, especially in the power system domain. The results of the review of the solution matrix and the interrelated technological challenges are the most important parts to be developed in the future. Developing a matrix with various renewable technology solutions can help solve RE challenges. The potential of the developed technological solutions is expected to be able to help and prioritize them especially cost-effective energy. In addition, technology solutions that are identified in groups can help reduce certain challenges. The categories developed in this study are used to assist in determining the specific needs and increasing transparency of the renewable energy integration process in the future.
... A decade ago, system operators regarded 10%-20% instantaneous shares of wind and solar penetration as the upper limit of operation [14,15]. Nowadays countries like Denmark, Ireland and Spain demonstrate successful examples of how power systems can be managed with 2-3 times higher shares if system flexibility is ensured [5]. ...
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Secure and reliable operation of power systems with high wind and solar shares requires system flexibility. In this paper, an hourly-based market and grid simulation model is developed to assess security and reliability of a power system with high wind and solar energy share. The model is applied to Turkey as an emerging G20 country that aims to supply its rapidly growing electricity demand from local renewables and lignite as well as nuclear energy. The most ambitious scenario that covers the 2016–2026 period assumes half of all electricity demand is supplied from renewables (30% wind and solar and 20% other resources). This is achieved by ensuring system flexibility through system-friendly location of wind and solar capacity, energy storage, flexible thermal generators, and demand response. Without system flexibility, 3% of renewable power is curtailed and redispatch share required for system security and reliability doubles from current levels. Moreover, additional transmission grid investments are needed. Improving system flexibility ensures secure and reliable operation but increases system costs by 1%–5% with each flexibility option providing different scale benefits, indicating the need for system-wide planning. As gas-based generation declines below 10%, accounting for energy security benefits will be important. On the other hand, coal supply remains around 25% depending on nuclear energy development. At this crossroad, Turkey needs to make its choices to transition to a secure, clean and affordable energy system. The study addresses quantitatively how the flexibility options contribute to such a transition, providing learnings for countries with similar conditions.
... However, clouds and winds are more complex to predict and could result in unplanned production drops. This technical barrier has been used as a break to renewable energy development because of their "unreliable nature" [62]. However, it must now be addressed: the best answer to such discontinued production is to exceed to total energy demand when possible and store this surplus to be reused when needed [63,64]. ...
Thesis
Direct Borohydride Fuel Cell (DBFC) is a promising alkaline fuel cell technology for portable and mobile applications. The use of solid sodium borohydride powder (NaBH4) as a substitute fuel to gaseous hydrogen (in a PEMFC) is advantageous in terms of storage and safety concerns. Once diluted in a strong alkaline solution, it is possible to electro-oxidize it through the Borohydride Oxidation Reaction (BOR) which presents interesting properties in terms of energy generation. However, this anodic reaction is really complex and involves several intermediate species and reaction pathways. Moreover, in the pas it has been mainly investigated in laboratory conditions and using Platinum Group Metals (PGM) electrocatalysts. Meanwhile, since the BOR occurs in alkaline media it is possible to use non-noble materials to catalyse this reaction. The main objectives of this PhD, falling within the MobiDiC project funded by the French National Research Agency (ANR), are therefore (i) to explore the effect of the borohydride concentration on the reaction kinetics on the noble catalysts and particularly on palladium (since the mechanism of the BOR is poorly known on this metal), (ii) to find a non-noble material active towards the BOR and (iii) to develop low-cost DBFC anode with an optimized architecture to maximize its efficiency towards the BOR.The results presented in this manuscript highlight the important poisoning of the PGM catalysts surface by intermediate species, which results in significant BOR efficiency loss mainly owing to slower charge transfer kinetics. Palladium hydrides were demonstrated to form in presence of borohydride, modifying the pathway of the reaction. In a second time, nickel nanoparticles, obtained by electrodeposition, were proven as performing non-noble catalysts only if their state of surface is precisely controlled and maintained metallic. DBFC performance matching the one using Pt-based anode was obtained with this Ni-based electrocatalysts supported on carbon paper. From this point, the anode support was replaced by Ni 3D structure and optimized to reach higher performance.
... Solar is expected to be the future main renewable resource in the world, and its development is currently very strong in countries such as Australia, Middle- east, Southern Europe and Northern Africa, where the solar resource can be better exploited all year around [404]. Maybe the main issue of solar energy (common to the majority of renewable energy sources) is that it is an energy resource intrinsically stochastic, so significant variations in solar energy production occur due to the presence of clouds, atmospheric dust or particles [405,406]. Thus, solar power prediction is extremely important to ensure a correct integration of this renewable source in the electric system. The basis to estimate solar radiation at any given location is to apply the classical astronomical equations [407], also known as Clear Sky (CS) model [408]. ...
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... Examples include; a surplus of supply for a windhydro power system due to the combination of high levels and inflows of lakes and rivers and good wind power supply in summer [15]; or solar surplus due to a mismatch between solar photovoltaic (PV) generation without storage and daily electricity demand [16]. These issues mean that integrating high percentages of renewable energy resources often requires a large quantity of under-utilized infrastructure, which will add significant costs [12,17] to the already large upfront cost of renewable energy technologies [18]. The investment required to meet PICs renewable energy targets is likely to come from https://doi. ...
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Pacific island countries are particularly susceptible to sea level rise as a result of climate change and also face high costs and energy security issues from imported fossil fuels. As a result many Pacific island countries are perusing 100% renewable energy targets. Due to challenges with variable renewable energy sources, detailed studies that balance renewable energy supply and demand at a fine temporal scale have been carried out for many countries to inform policy directions. Despite having adopted renewable energy targets, most Pacific island countries have not been subject to the same level of detailed analysis in the academic literature. In addition, the results from other countries are not directly applicable given the particular local resources, climatic conditions and economic situation of Pacific island countries. In this paper, focusing on the case of Samoa, we use an approach based on historical electricity demand and generation time-series data to investigate future scenarios that achieve very high percentages of renewable electricity. The results show that scenarios of high proportions (above 90%) of renewable energy generation coupled with storage (28%–37% of direct solar, 17%–30% of stored solar and 25%–40% of hydro) are economically viable (Net Present Value >0) but, there is a significant trade-off between percentage of renewable supply and affordability. These results have important implications for energy policy directions for Samoa and are directly applicable to many other countries in the Pacific.
... As previously stated, solar and wind energy resources are inherently variable both in time and space. Their intrinsically stochastic nature is commonly seen as a significant threat to a hybrid power system's stable and reliable operation [15,16]. However, this should not be perceived as an impediment to their further deployment but rather a challenge that can be overcome with sufficient research and development efforts, as recent studies have discussed [17,18]. ...
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The concept of renewable energy sources complementarity has attracted the attention of researchers across the globe over recent years. Studies have been published regularly with focuses on aspects such as new metrics for complementarity assessment, the optimal operation of hybrid power systems based on variable renewables, or mapping resources complementarity in a specific region. This study targets the present literature gap, namely a lack of complementarity study covering explicitly the whole World, based on the same data source and methodology. The research employs Kendall's Tau correlation as the complementarity metric between global solar and wind resources and a pair of indicators such as the solar share and a sizing coefficient usually applied in the domain of hybrid generators. This method allows to conduct a preliminary estimation of a solar and wind energy hybrid generator based on a daily demand of 1 kWh. The data series employed in this study come from NASA's POWER Project Program, covering the years 2001-2020. This work provides an interesting insight into the global variability of the complementarity between these two variable energy sources. Significant findings of this paper include that Kendall's Tau ranges between-0.75 and 0.75, in line with previous research for specific regions, thus providing a theoretical maximum for planning. Additionally, the results suggest that in most tropical and subtropical areas, the hybrid solar-wind generator should be dominated by the solar portion to minimize the variability of the total daily energy produced.
... The regional pathway to mitigating energy poverty proposed in this paper is a more unified structure which allows an effective sharing of excess electricity from the individual countries within the region. Lastly, the narratives of the bandwagon who call for a so-called just transition or low-carbon transitions have been avoided in this paper [80][81][82][83][84]. While the world can benefit from a diversified energy mix that is more renewables focused, SSA and by extension the global south will benefit more, FIRST, from having electricity that is stable, cheap, and can continue to meet her energy needs in the long-term. ...
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Persistent low electricity access continues to plague Sub-Saharan Africa (SSA) and has been made more obvious due to the precarious nature of adopted energisation schemes across the region. The absence of resilient elec- trification schemes within most countries in SSA portends grave danger for the region. Regional cooperation (like the integrated European Union (EU) electricity market) can guarantee stable, secure, and affordable electricity supply across regions when properly regulated. However, such a template as is obtainable in Europe may be impossible to replicate within SSA owing to the peculiar problems, local controversies and very wide variation in regional electrification statistics that exist within the region. This research work pertinently examines the power pools within SSA and argues that improved regional cooperation, especially in tackling the issue of energy poverty and achieving “universal energy access (SDG 7)”, should be pursued on the platform of national energy sufficiency. This argument draws extensively from the geopolitics within the region by different actors and the impact of national interests on regional cooperation. While we do not seek to oppose regional cooperation in electricity trading, we emphasize the need for nations within the region to strive for some level of national energy security through carefully crafted policies and road maps that resonate with their local realities. Regional cooperation should strive to standardise electricity access benchmarks and facilitate technology transfer through existing or improved instruments rather than pushing for more integrated electricity networks.
... Concerning the above, they also report that the local weather and the geographical location of the buildings have a strong influence. As Sovacool [104] points out, the energy production of solar systems varies with the season; the time of day; and the presence of fog, clouds and rain. Despite the good geographical situation and the climate of the Iberian Peninsula compared to other European countries [105], all participants from the North of the Peninsula point out that factors such as the low value of solar irradiation and the reduced number of daily sunshine hours in autumn and winter prevent these facilities from being repaid over a reasonable period. ...
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For more than a decade, the European Union has been implementing an ambitious energy policy focused on reducing CO2 emissions, increasing the use of renewable energy and improving energy efficiency. This paper investigates the factors that hinder the application of renewable energy technologies (RETs) in existing university buildings in Spain and Portugal. Following a qualitative methodology, 33 technicians working in the infrastructure management offices of 24 universities have been interviewed. The factors identified have been classified into economic-financial, administrative and legislative barriers, architectural, urban planning, technological, networking, social acceptance, institutional and others. It is concluded that there have not been sufficient economic incentives to carry out RETs projects in this type of building. Conditioning factors can act individually or jointly, generating a greater effect. Most participants consider that there are no social acceptance barriers. Knowledge of these determinants can facilitate actions that help implement this technology on university campuses in both countries.
... Cloud cover, shape, thickness, and height are many variables that are difficult to predict and are unique day-to-day. As a result, solar energy is invariably intermittent, posing a significant challenge in its widespread usage [20,23]. This causes energy fluctuations and uncertainties that could lead to subsequent load balancing issues in power systems [9]. ...
... As the intermittency of HRES system is directly dependent on the parameters such aswind speed, air density, irradiance & environmental temperatures. The intermittency within a system is directly proportional to these parameters; so, if there will be more fluctuations within a parameter, the more will be the overall intermittency within a system [16]. ...
Chapter
Due to the fluctuations in supply and demand in energy generated through hybrid renewable sources, there will be an intermittency leading to an impact on the productivity and utilization of grid-connected systems. These fluctuations are caused due to the nature of variability of renewable energy systems. The variable irradiance on solar panels and the wind speed along with air density changes leads to huge variations in output power generations through hybrid renewable energy system (HRES). The present paper gives an insight about the various conventional and modern approaches which are utilized to reduce the intermittency within a hybrid renewable energy-based system. This paper also highlights the usage of optimization techniques and predictive analytics for the forecasting of energy demand.
... Thus, various power converters and control strategies are developed for controlling and monitoring active and reactive power, which encounters challenges due to the intermittent nature of renewable energy sources. This kind of power fluctuation poses severe problems for power grid companies such as power quality, load leveling, generation dispatch control, and electric system reliability [8]. The duck curve shown in Fig. 3 can be used to illustrate the considerable challenge of accommodating solar and wind energy, and the potential for overgeneration and curtailment. ...
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A hybrid renewable energy source (HRES) consists of two or more renewable energy sources, suchas wind turbines and photovoltaic systems, utilized together to provide increased system efficiency and improved stability in energy supply to a certain degree. The objective of this study is to present a comprehensive review of wind-solar HRES from the perspectives of power architectures, mathematical modeling, power electronic converter topologies, and design optimization algorithms. Since the uncertainty of HRES can be reduced further by including an energy storage system, this paper presents several hybrid energy storage system coupling technologies, highlighting their major advantages and disadvantages. Various HRES power converters and control strategies from the state-of-the-art have been discussed. Different types of energy source combinations, modeling, power converter architectures, sizing, and optimization techniques used in the existing HRES are reviewed in this work, which intends to serve as a comprehensive reference for researchers, engineers, and policymakers in this field. This article also discusses the technical challenges associated with HRES as well as the scope of future advances and research on HRES.
... Traditionally, U.S. electricity generation in the has relied on large, centralized assets, such as coal-fired or nuclear power plants, to achieve economies of scale and supply cheap, reliable power to consumers (Sovacool, 2009). However, supply-side factors, such as the relative price competitiveness of alternative energy sources, environmental/ pollution regulations, and others (e.g., Jenner et al., 2012), have triggered decline in sectors like the coal industry (Carley & Konisky, 2020). ...
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While the concept of rurality has been debated in academic and professional literature for decades, less research has been done on a practical typology that can guide localized economic development strategies. This paper adds to the growing body of literature in search of a more nuanced definition of rural by applying unsupervised machine learning (ML) to the abundance of existing county-level data in the United States. The authors illustrate how this method can lead to a new county typology, named after economic development strategies, that accounts for idiosyncrasies in resources, opportunities, and challenges. This research serves as a practical step toward tractable, heterogeneous classifications that can inform the work of federal, state, and local policy makers, economic development practitioners, and many others.
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Numerical weather prediction (NWP) and machine learning (ML) methods are popular for solar forecasting. However, NWP models have multiple possible physical parameterizations, which requires site-specific NWP optimization. This is further complicated when regional NWP models are used with global climate models with different possible parameterizations. In this study, an alternative approach is proposed and evaluated for four radiation models. Weather Research and Forecasting (WRF) model is run in both global and regional mode to provide an estimate for solar irradiance. This estimate is then post-processed using ML to provide a final prediction. Normalized root-mean-square error from WRF is reduced by up to 40-50% with this ML error correction model. Results obtained using CAM, GFDL, New Goddard and RRTMG radiation models were comparable after this correction, negating the need for WRF parameterization tuning. Other models incorporating nearby locations and sensor data are also evaluated, with the latter being particularly promising.
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With the reduction in fossil fuels and their environmental impacts, the use of solar cells as green energies in various countries is expanding. It is certainly neither effective nor necessarily possible to generalize a single specific model for different countries considering their different conditions. Therefore, this study, with the aim of providing a business environment analysis model for the third-generation solar energy market in Iran, first, used a systematic search by using the meta-synthesis method to extract important factors. Thirty-four variables in eight dimensions were found to be effective in the solar energy business in Iran. Then, an interpretive structural modeling was provided to derive a priority diagram. Finally, the causal graph and the stock and flow diagram were drawn and the behavior of the variables was examined under three scenarios. The results indicated that using solar cells to generate electricity is economically efficient in the long run and can help to protect the environment.
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Indonesia intends to increase the renewable energy ratio to at least 23% from the energy mix generated by 2025. This target is also in line with the Paris Agreement that Indonesia ratified in October 2016. However, renewable energy capacity has not been significant, as 11.38% of the total on-grid power capacity (MEMR, 2021). More than 90% of renewable comes from hydropower and geothermal, and only a limited capacity comes from wind and solar energy. On the other hand, wind and solar energy potential are enormous for energy generation in Indonesia. One of the barriers that hinder the use of both is their intermittent nature so that they are not economically profitable and can disrupt the existing power grid. Energy storage systems (ESS) can reduce this intermittent problem as frequency regulators and voltage support to the grid. This paper reviews the potential and challenges of energy storage and renewable power generation, especially wind and solar power. This paper also outlines lessons learned from energy storage systems that have been implemented and are still under development. The discussion focuses on the types of energy storage suitable for applications in Indonesia.
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This paper demonstrates a successful dispatching scheme of slider-crank wave energy converter (WEC) production using two different kinds of energy storage systems, namely, (i) Li-ion battery and (ii) Supercapacitors (SC). The performance of two energy storage systems has been compared in order to develop the most economical energy storage system for WEC hourly dispatching scheme. The cost optimization of the energy storage system considering both cycling and calendar aging expenses is made based on its usage of depth of discharge (DOD). In this study, the extensive simulation is conducted in MATLAB/Simulink platform, and it is found that SC is a better candidate than Li-ion battery in terms of economic assessment for hourly dispatching WEC power.
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Chapter
This chapter discusses the concept of internal environmental conflicts from the perspective of negative impacts caused by renewable energy projects in Brazil and Germany. It identifies the significant positive and negative effects based on a literature review to show that the pathway to reducing GHG emissions to protect the climate requires technical and economic feasibility and the prevention of environmental impacts. First, this chapter summarizes the technical aspects and co-benefits of renewable energy sources other than climate protection. It then analyzes the adverse effects of solar, wind, hydropower, and biomass plants in Brazil and Germany, together with connected impacts (energy transmission and storage). Finally, to achieve a conceptual reflection of internal environmental conflicts, this chapter discusses them in the legal analysis, paving the way to find legal solutions in concrete decision-making. Because environmental impacts are numerous and include different areas, the example of the internal conflicts in law is limited to biodiversity effects.
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Supplying the increasing energy demand of communities both economically viable and environmentally friendly is among the primary challenges of the present century. In this regard, the current study aims to suggest a proper approach, in terms of economic and environment, to supply the energy demand of Eram Campus, Shiraz University. Pre-studies are carried out to realize the energy demand, primary energy potentials, and geographical constraints of Eram Campus. In the present study, simulations, optimizations and sensitivity analysis are performed to explore the feasibility of utilizing smart hybrid renewable energy system to meet the load demand of the Eram Campus. The results indicate that the suggested energy system consists of micro gas turbine (combined heat and power) power plant, thermal boiler, converter, photovoltaic panel, pumped hydro energy storage and predictive (smart) controller. To make use of the proposed power plant, 15$M is needed for initial capital cost. The levelized cost of energy and net present cost of the system is 0.09 $/kWh and 42.5 $M, respectively. Based on the obtained results, using the proposed energy system reduces the annual carbon dioxide production of the Eram Campus by 8000 megatonnes compared using the existing one. Moreover, the calculations reflect that the impacts of economic indexes variations, escalation of energy demand and energy consumption pattern change on the characteristics of the energy system are considerable. The optimum sizings of the gas turbine, thermal boiler, photovoltaic panel, converter and pumped hydro storage should be 2650 kW, 17 MW, 13754 kW, 4995 kW and 70 strings to meet the increase of 50 per cent in energy demand in the most economical strategy. It is worth mentioning that by reducing the energy consumption in specific time steps (1 per cent of the total energy demand), the net present cost and Levelized cost of energy would significantly decline 6 and 15 per cent, respectively.
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Renewable energies have an essential role in reducing various forms of pollution. The policymakers within the European Union place more and more emphasis on the replacement of internal combustion engine vehicles with electric vehicles in order to reduce emissions. The aim of this research is to analyze the current trends in producing and using renewable energy until 2028 and to estimate the impact of replacing the current internal combustion engine cars with electric cars. The significance of this study emerges from the estimation of the amount of electricity needed to replace current cars with electric cars and if it can be covered from green sources, based on the forecast of green energy until the year 2028. In addition, we also calculate in this study the impact on the public budgets of the European Union member states, as a result of the reduction of excise duties for fuels, following the reduction of their consumption. The research was carried out based on the extensive literature on the subject and data from Eurostat. The data used in this study are from 1990 to 2021. In this research we have used the IBM SPSS application with two of the most used forecasting algorithms: exponential smoothing model and autoregressive integrated moving average (ARIMA), based on the statistical analysis of the historical data. The estimated results showed that the replacement of traditional fuels will lead to an increase of 12.18% for electrical energy, and it could be covered 100% from green sources, if needed, even before 2028. There are many implications of this study for policymakers and the population. The results show that we still need policies to stimulate electricity production from renewable sources. There is a challenge regarding reducing government revenue due to fuel excises, which can be compensated by updating tax policies, with an impact on population and living standards. Furthermore, maintaining and adapting support schemes for electric cars, as well as expanding electric car infrastructure and smart grids are also challenges that need to be addressed by the policymakers and the industry.
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This chapter challenges those who believe that energy efficiency measures are unreliable, unpredictable, or unenforceable and that, therefore, energy efficiency cannot be relied upon as a utility system resource. This myth has been around for a long time and continues to surface periodically, despite contrary evidence and rebuttals from industry analysts (Lovins, 1994; Vine and Kushler, 1995; Geller and Attali, 2005; Sovacool, 2006). For example, two economists at the Massachusetts Institute of Technology, Paul Joskow and Donald Marron (1993), assert that "energy conservation should be conceptualized as a customer service and a customer resource, not as a utility resource that is equivalent to a utility supply curve." Len Brookes (1990) concluded that those who advance energy efficiency as a "fifth fuel" comparable to supply perpetuate a gross fallacy, and that efficiency practices, at best, represent only "a very oblique approach that seems to owe more to the current tide of green favor than to sober consideration of the facts." Geoffrey Greenhalgh (1990) warns that "presenting conservation as the equivalent to a new supply fosters the illusion that energy uses can be continued unchecked." And, more recently, the National Association of Home Builders (2005) commented that regulatory complexity and lack of information among construction companies make relying on energy efficiency codes "effectively unenforceable." Unfortunately, a preference for supply-side options has several negative ramifications, including: • Investment in energy efficiency by consumers (residential and non-residential) is less than optimal - in fact, in many cases, there is no investment. • Energy efficiency is often overlooked as a solution in the energy policy arena. Instead, state and national energy solutions focus on energy supply, and energy efficiency is not seen as a reliable resource (with some exceptions - e.g., California, the Pacific Northwest, New England, and a few other states that generally have long records of successful energy efficiency programs). • Energy efficiency is not typically seen as a solution in the environmental policy arena - instead, air quality regulators (e.g., see the Clean Air Act Amendments (CAAA) of 1990) focus on traditional technical solutions (e.g., scrubbers) and supply side disincentives (e.g., NOx and SO 2 regulations) without considering energy efficiency as a viable clean air strategy. • Energy efficiency investments by utilities are sub-optimal, in part because of doubts by utility planners and management, and in part because opponents of these programs promote this myth in order to influence regulators to not support utility energy efficiency programs. At least half the states have no real utility sector energy efficiency programs, and just 20 states account for 90% of total national spending on such programs (York and Kushler, 2005). To examine the benefits of energy efficiency practices in greater detail, we begin our examination by first reviewing the concepts of reliability, predictability, and enforceability within the context of utility system planning and operations, for it is also important to consider these issues for supply side resources. In this section, we discuss risk and uncertainty regarding the supply side components of electricity generation, transmission and distribution, and describe how energy efficiency can help mitigate those risks. We also highlight some recent regulatory activities promoting energy efficiency explicitly for its risk-reduction value in resource procurement. This section presents a striking example of how energy efficiency has played a key role in preserving utility system reliability, in the case of the 2001 California energy crisis. In the next section, we examine the reliability and predictability of energy efficiency from an evaluation perspective: we review the experience of evaluating energy efficiency programs and technologies in the last 20 years, the development and implementation of evaluation protocols, and key findings resulting from the evaluation of energy efficiency programs. In Section 4, we examine methods for ensuring and enforcing the performance of energy efficiency measures, programs, and portfolios. In the last section, we summarize our findings and conclude that energy savings from energy efficiency programs are sufficiently reliable, predictable, and enforceable to allow energy efficiency to be incorporated as a utility system resource.
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The nuclear power industry is simultaneously experiencing the best and the worst of times. Since the Three Mile Island incident, the industry has been met with great government and public concern over the safety of nuclear power and has accordingly made efforts to improve safety procedures. Although pending legislation would streamline the licensing process for nuclear power plants and encourage design standardization, the future of nuclear power is more importantly dictated by the amount of electricity needed by Americans in the coming years, a subject of great debate. 22 references, 2 figures, 2 tables.
Article
This paper provides an update on the U.S. distribution of effective load-carrying capability (ELLC) for photovoltaics by analyzing recent load data from 39 U.S. utilities and time-coincident output of PV installations simulated from high-resolution, time/site-specific satellite data. Results show that overall regional trends identified in the early 1990s remain pertinent today, while noting a significant increase in PV ELCC in the western and northern United States, and a modest decrease in the central and eastern United States.
Article
The California Power Authority (CPA) is committed to increasing the use of renewable energy supplies--such as photovoltaics and wind--as a hedge against price fluctuations of electricity and natural gas. The CPA wants to own and operate an adequate supply of reserve generation that: - Can be deployed quickly in response to severe summer peak loads, unexpected loss of base and intermediate generation units, and failure of critical transmission facilities; - Will minimize the reliance on spot market purchases during periods when the State is most vulnerable to price gouging from private generators.
Article
Wind is the world's fastest growing electric energy source. Because it is intermittent, though, wind is not used to supply baseload electric power today. Interconnecting wind farms through the transmission grid is a simple and effective way of reducing deliverable wind power swings caused by wind intermittency. As more farms are interconnected in an array, wind speed correlation among sites decreases and so does the probability that all sites experience the same wind regime at the same time. The array consequently behaves more and more similarly to a single farm with steady wind speed and thus steady deliverable wind power. In this study, benefits of interconnecting wind farms were evaluated for 19 sites, located in the midwestern United States, with annual average wind speeds at 80 m above ground, the hub height of modern wind turbines, greater than 6.9 m s-1 (class 3 or greater). It was found that an average of 33% and a maximum of 47% of yearly averaged wind power from interconnected farms can be used as reliable, baseload electric power. Equally significant, interconnecting multiple wind farms to a common point and then connecting that point to a far-away city can allow the long-distance portion of transmission capacity to be reduced, for example, by 20% with only a 1.6% loss of energy. Although most parameters, such as intermittency, improved less than linearly as the number of interconnected sites increased, no saturation of the benefits was found. Thus, the benefits of interconnection continue to increase with more and more interconnected sites.
Article
This essay is divided into two parts. The first is a factual description of the Washington Public Power Supply System’s history. The second is an analysis of why things went wrong. There is no attempt made to find scapegoats: the purpose is to place the Supply System in a larger economic and institutional context. Nor does this work attempt to analyze the very complex legal problems associated with the WPPSS default, this is a major topic in itself.
Article
This is a study to quantify U.S. wind power at 80 m (the hub height of large wind turbines) and to investigate whether winds from a network of farms can provide a steady and reliable source of electric power. Data from 1327 surface stations and 87 soundings in the United States for the year 2000 were used. Several methods were tested to extrapolate 10-m wind measurements to 80 m. The most accurate, a least-squares fit based on twice-a-day wind profiles from the soundings, resulted in 80-m wind speeds that are, on average, 1.3-1.7 m/s faster than those obtained from the most common methods previously used to obtain elevated data for U.S. windpower maps, a logarithmic law and a power law, both with constant coefficients. The implication is that U.S. windpower at 80 m is enormous and much greater than previously thought. It was found that 25.2 percent of all stations (and 44.6 percent of all coastal/offshore stations) are characterized by mean annual speeds >= 6.9 m/s at 80 m, implying that the winds over possibly one quarter of the U.S. are strong enough to provide electric power at a direct cost equal to that of a new natural gas or coal power plant. The greatest previously uncharted reservoir of windpower in the continental U.S. is offshore and near shore along the southeastern and southern coasts. The other great reservoirs, previously charted, are the north- and south-central regions. The five states with the highest percentage of stations with annual mean 80-m winds >= 6.9 m/s were Oklahoma, South Dakota, North Dakota, Kansas, and Nebraska. Other findings are (1) monthly and annual mean wind speed (and wind power) peaks in the afternoon, when electricity demand is usually high; (2) winds are Rayleigh in nature, and actual wind power at any hour of the day is close to Rayleigh wind power; (3) the standard deviation of the wind speed averaged over multiple locations is less than that at any individual location; (4) when multiple wind sites are considered, the probability of no wind power production at a given instant is substantially reduced in comparison to when one wind site is considered. In sum, a network of wind farms in locations with high annual mean wind speeds can provide a reliable and abundant source of electric power.
Article
This paper explores the data and models necessary to evaluate the reliability of wind generators that are geographically distributed in a utility system. A case study is conducted using California data. Results on capacity credit are found to depend upon the size of the region, the reliability of the wind regime, the existing power system generator mix, and the penetration of the wind generators.
Article
In situ measurements of wind speed from 28 wind-monitoring sites across North Dakota, Minnesota, Iowa, and Kansas were used in conjunction with a turbine manufacturer's power curve to produce multiple time series of energy production. In this study, a regional wind farm was designed with equal capacity at all 28 sites. Although some sites have better wind resources than others, the purpose of this study was not to optimize the geographic distribution of wind turbines, but to investigate the variability of wind energy generation across the region. The production from this hypothetical regional wind farm was compared to production from a single location. For this study, the location of the single site is rotated among the 28 various monitoring locations. The comparison of energy production from the individual sites versus production from a regional wind farm showed the variability in energy production was reduced by a factor of 1.75–3.4.
Article
Europe currently has by far the highest installed wind power capacity of all re-gions in the world. However, this is not due to Europe being the best possible place to build wind power, but rather to a favourable political climate. Owing to the rapidly increasing use of wind power, the aspect of integrating high levels of wind power into the grid is becoming more and more important. Because of the intermittent nature of wind, the quality of the electricity is af-fected by power fluctuations that can occur for short periods of time, such as a few seconds up to periods of a couple of months. The short term fluctuations even in small regions are significantly smoothed by increasing the number of turbines while long term variability decreases when the wind power is harvested from a large area. An area as big as Europe already shows good pros-pects for a smoothing of wind power output through the spatial distribution of generation. Fur-thermore there are areas surrounding Europe with high resources where harvesting of wind power could be economical, even including the costs of transport to Europe, using efficient transmission systems (such as High Voltage Direct Current HVDC) to harvest wind power for a European electricity supply. However, the variability significantly decreases when the wind power is harvested from such a large area. This paper presents analyses of power output data of individual wind turbines, wind farms, and clusters of wind farms on a wide range area up to some thousands of kilometres. With growing distances between wind farms a smoothing of the total power output occurs due to the lower correlation of wind speed. At high penetration this change of the temporal behaviour of the total wind power production significantly influences the backup systems necessary to provide a reliable electricity supply. By comparison of the electricity con-sumption and the available wind power the effect of spreading out wind energy generation to a large area is shown. Using only the existing storage capacity in Europe, a big proportion of the total electricity demand could be supplied by wind energy. The calculations are based on data from the German "250 Megawatt Wind" programme and from the European Centre for Medium-Range Weather Forecasts (ECMWF).
Chapter
Overall, the United States now uses 47% less energy per unit of economic output than it did 30 years ago, cutting today's energy costs by a billion dollars a day - like a huge universal tax cut that also cuts the federal deficit. Far from dampening global development, lower energy bills accelerate it.Andthere's plentymorevalue to capture. The waste heat thrown away by U.S. power stations - a fifth more energy than Japan uses for everything - could be lucratively recovered and reused if "combined-heatand- power" were encouraged as it is in Europe. Converting coal at the power plant into incandescent light in the room is only 3% efficient. And around 20 huge power plants spew out CO2 just to run U.S. equipment that is turned off (Lovins, 2005). Why do such inefficiencies continue? Many economists, policy analysts, and politicians believe that the country has already captured its energy efficiency potential, and that (as a result) not much promise is left. For example, in their comprehensive assessment of 20 years of industrial energy efficiency projects, Anna Shipley and R. Neal Elliot (2006) conclude that "a recurring theme offered by those opposed to the funding of industrial energy efficiency efforts has been that companies have already realized all the cost-effective industrial energy efficiency opportunities that exist." Richard N. Cooper (2005) notes that "there are many attractive ideas out there [for addressing energy challenges]," including energy efficiency practices and small-scale renewable energy systems like wind turbines. "But when one looks quantitatively at the possibilities for mobilizing them, it is clear that many can play only a niche role" (p. 271). Paul Joskow (1995) argues that "estimates of un-tapped economical energy-efficiency opportunities are nothing more than fantasy" (p. 531).
Article
We analyse two popular strategies for reducing fossil-fuel carbon dioxide (CO2) emissions: revitalizing nuclear power, and improving energy efficiency. Under highly favourable assumptions for nuclear power in scenarios of moderate to high energy growth, we find that even if large nuclear plants (1 000 MW) could be built every one to three days from now until 2025 (which is impossible in the Third World), global CO2 emissions would still continue to grow. Thus, nuclear power cannot contribute significantly to abating greenhouse warming, except possibly in scenarios of low energy growth for which the problem is already largely ameliorated by efficiency improvement. In the USA — the world's largest producer of CO2 — each dollar invested in electric efficiency displaces nearly seven times as much CO2 as a dollar invested in nuclear power. Even if the most optimistic aspirations for the future economics of nuclear power were realized today, efficiency would still displace between 2.5 and 10 times more CO2 per unit investment. We conclude that revitalizing nuclear power would be a relatively expensive and ineffective response to greenhouse warming, and that the key to reducing future CO2 emissions is to improve the energy efficiency of the global economy.
Article
Luis E. Echávarri has served as Director-General of the Organisation for Economic Co-operation and Development Nuclear Energy Agency (NEA) since 1997. He began his career as an engineer, and while at Westinghouse became Project Manager of the Lemoniz, Sayago, and Almaraz nuclear power plants in Spain. In 1985 he became Technical Director of the Spanish Nuclear Safety Council (CSN), rising to Commissioner in 1987. From July 1995 until his appointment to the OECD, he served as Director-General of the Spanish Nuclear Industry Forum.
Article
Dramatic improvements in renewable energy and small-scale distributed generation (DG) technologies have been made in the last twenty years. Nevertheless, they remain underutilized in the American electric utility system. Despite the immense environmental, technical, and financial promise of renewable energy systems and DG technologies, such generators still constitute a very small percentage of electricity generation capacity in the United States. This relative neglect occurs despite remarkable gains in their technical performance and reductions in their cost of producing power--the result (in part) of dramatic government support for several decades. Moreover, the technologies often demonstrate great environmental benefits that appeal to policymakers and consumers. At the same time, they offer ways to enhance strained distribution and transmission networks. This project attempts to answer the apparently paradoxical question: why do new energy technologies that offer such impressive benefits also find the least use? The dissertation emphasizes how the history and culture of the community of electricity producers and users helps explain why the new technologies have seen little use. Going beyond technical explanations of alleged low capacity factors and high capital costs, it focuses on the social nature of decision making among participants in the electric utility system. The approach not only helps us understand the glossing over of renewable energy and distributed generation technologies, but also suggests ways of overcoming the barriers faced by their advocates. System requirements: PC, World Wide Web browser, and PDF reader. Available electronically via the Internet. Title from electronic submission form. Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 2006. Vita. Abstract. Includes bibliographical references.
Article
The combination of wind energy generation and energy storage can produce a source of electricity that is functionally equivalent to a baseload coal or nuclear power plant. A model was developed to assess the technical and environmental performance of baseload wind energy systems using compressed air energy storage. The analysis examined several systems that could be operated in the midwestern United States under a variety of operating conditions. The systems can produce substantially more energy than is required from fossil or other primary sources to construct and operate them. By operation at a capacity factor of 80%, each evaluated system achieves an effective primary energy efficiency of at least five times greater than the most efficient fossil combustion technology, with greenhouse gas emission rates less than 20% of the least emitting fossil technology currently available. Life-cycle emission rates of NOx and SO2 are also significantly lower than fossil-based systems.
Article
Improving economics, environmental benefits, supportive state policies, and the rising costs of competing fuels are all contributing factors towards greater market regulatory interest in wind energy. However, wind energy poses several operational and planning challenges, some of which are beginning to be addressed. While the challenges are significant, they are not insurmountable.
Article
This paper discusses the key issues that confront power system planners and operators when integrating wind power plants into the electric power system. A key question is how the variations in wind plant outputs affect the operation of the power system on a daily basis and what the associated costs are. These costs are lower than initially expected by some utility engineers. The main reason for this is that wind tends to behave more like negative load than traditional firm-block generation, and the power system has been designed to handle significant load variations on a routine basis. This paper summarizes the key results of wind integration studies conducted to date and provides insights from individual studies. The studies present simulations of system operations that employ well-established production-costing and unit-commitment computational tools.
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