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This paper presents a systematic literature review of urban wind energy harnessing in built environments. In line to foster decarbonisation in urban areas of tropical countries with decentralised renewable energy technologies, such as small wind turbines in buildings, this research has been carried out. To provide a comprehensive foundation on the topic, urban wind assessment research for various purposes was reviewed, where 48 studies for energy harnessing purposes were classified by country, region and methods. The methodologies are divided into six stages, of which environmental assessment and resilience analysis are scarce. Due to tropical countries being exposed to atmospheric events that historically cause human and material losses, potential future research could be made in line with resilience analysis through metrics that are key to the proper mass deployment of building-integrated wind turbine systems. Of 66 methods for wind prospecting, the most used are on-site measurement, computational fluid dynamics simulation and numerical climate prediction, which represent 49 %, 22 % and 17 %, respectively. Other decision-making techniques are presented with the aim of addressing new ways in strategic planning to promote the use of this technology. [Display omitted] • Urban wind energy research does not deem energy resilience analysis. • Few evaluations of urban wind energy have been carried out in the tropics. • Hurricanes represent a hazard for building-integrated wind turbines. • On-site measurement and CFD simulation are the most adopted methods. [ABSTRACT FROM AUTHOR]

Brazil is a case of the achievement of a high share of wind energy integration to an interconnected power system in an emerging market. A series of successful energy supply programmes and a strong renewable-oriented finance framework implemented since 2002, have promoted alternative renewables – wind installed capacity increased over 22-fold from 927 MW in 2011 to 21 GW in 2022, reaching 11.77% of total procured power. From this, about 90% are concentrated in Brazil's least developed region, the Northeast, where wind investment should create jobs and propel socioeconomic development. Despite that, there is no studies specific assessing the regional and economy-wide effects of those programmes, gap that this paper aims to fill by applying the regional Computable General Equilibrium (CGE) model TERM-BR10. We assess that by modelling an alternative scenario for the period 2010-19 based on an official electricity matrix built in 2010, that projected 3.4 additional GW of wind power while not considering all the success of renewable policies, against the observed installed capacity expansion, where wind power was 3.7 times higher than what had been planned. Our results show that in the absence of renewable policies, Brazil would have faced economic losses such as GDP (−0.27%) and investment (−4.76%). The Northeast region would have been the most impacted in terms of GDP (−1.3%), real wage (−2.99%) and employment creation (−0.1%). We propose that such socioeconomic co-benefits are incorporated in energy planning, which could promote regional equality through renewable energy expansion. • Wind power capacity increased over 20-fold from 2011 to 2022. • 90% are in the poorest region where policies propel development and job creation. • Policy absence would entail a GDP loss of 0.27% nationally and of 1.3% in the region. • Negative impacts to labour market are mostly over skilled jobs. [ABSTRACT FROM AUTHOR]

For twenty years, social scientists have used place concepts to understand energy infrastructure siting. Much of this research stemmed from attempts to provide theoretical explanations that avoid pejorative NIMBY (Not in My Back Yard) assumptions about community objections. Despite a burgeoning literature, a comprehensive review of place-related energy infrastructure research is lacking. This paper addresses this gap for the first time by collating and systematically reviewing a corpus of 190 articles published between January 1999 and March 2022, using search terms combining 'energy' and five place concepts (place attachment, sense of place, place identity, identity of a place, place-technology fit). Content analysis revealed the application of place concepts most frequently to wind energy, as well as nuclear power, fossil-fuel extraction and energy distribution; a high number of journal outlets (n = 76); a prevalence of single case study and survey methods; geographical concentration in developed countries, and a high prevalence of female authors. Bibliometric analysis of key words indicated a hub and spoke structure centered on the term place attachment, with low levels of coherence. 8 research clusters were identified comprising disparate technologies, geographical contexts, concepts and methods. Two of the search terms (identity of a place, place-technology fit) had low prevalence. Analysis revealed the application of place concepts to be highly varied, with 15 place concepts identified that are often not the primary focus of research, and sometimes used superficially. To improve coherence, cumulative learning and rigour in future studies, a lexicon of place definitions and specific recommendations are provided. • A corpus of 190 articles draws on place concepts to research energy infrastructure. • This literature spans diverse technology sectors, countries and numerous journals. • Studies on renewable energy, in particular wind energy, are most prevalent. • Eight clusters with weak coherence are identified, indicating a fragmented literature. • Recommendations to improve coherence, cumulative learning and rigour are provided. [ABSTRACT FROM AUTHOR]

Australia has significant offshore wind resources that can support ever-increasing power demand and hence provide a long-term contribution to the net-zero target by 2050. Although some offshore wind farm projects are proposed in Australia, the industry is not mature enough to justify the benefits and display economic opportunities. More specifically, the techno-economic analysis of offshore wind energy has not been systematically mapped in Australia. Therefore, the investigation of the spatial variation of technical feasibility and economic potential of offshore wind is vital to identify the potential regions and to develop strategies for future offshore wind farm developments in Australia. This paper presents detailed mappings of the techno-economic potential of offshore wind energy in Victoria-Tasmania's exclusive economic zone. Offshore wind energy resources are assessed in the paper in terms of energy availability and variability and the feasibility of various offshore wind technologies is investigated, including turbines, foundation types and transmission topologies. In addition, the high-fidelity life-cycle cost models and two innovative evaluation matrices are developed to assess the economic potential of offshore energy farms in South-eastern Australia. The impact of local power system regulation costs and future carbon prices on the viability of offshore wind is also investigated in this paper. It is concluded that the detailed mapping approach and analysis in the paper can provide a systematic tool for industry partners, investors and policymakers at the pre-planning stage of developing offshore renewable energy systems. • The technical feasibility of offshore wind is mapped under various constraints. • The novel LACE and high-fidelity LCC assessment models are developed. • The techno-economic potential is systemically mapped in South-eastern Australia. • The impacts of electricity market regulation and future carbon prices are studied. [ABSTRACT FROM AUTHOR]

Ocean renewables (such as offshore wind and wave) are abundant and essential energy resources for supporting future emission-free targets. However, their energy intermittency and high cost have hindered commercialization and wide-scale implementations of these ocean energy technologies. This paper focuses on both issues and aims to increase the dispatchability of ocean energy farms by investigating the potential of a hybrid wind and wave energy platform with energy storage systems (ESS). This research introduces an innovative method to assess the necessary ESS capacity for offshore renewable energy farms, ensuring energy dispatchability to the local demand. In addition, the key criteria and the economic feasibility of deploying ESS in offshore energy farms are also discussed. A life-cycle cost model is presented that quantitatively compares different farm configurations, specifically a standalone offshore wind farm and a hybrid configuration incorporating both wind and wave generation systems. The results indicate that the combined wind and wave energy farm significantly reduces the ESS requirement and provides competitive lifecycle costs compared to the stand-alone wind energy farm, though the amount of these benefits vary on the local resource characteristics. The quantitative assessment presented in this study also provides realistic and practical justifications for combined energy farms that complement statistical conclusions derived from variability indexes in previous studies. [Display omitted] • The techno-economic benefits of combined wind–wave farms are quantified. • A novel method of sizing and evaluating ESS for offshore farms is proposed. • The combined energy farm reduces ESS requirement compared to wind-only farms. • The benefits of combined energy farms are sensitive to the resource characteristics. [ABSTRACT FROM AUTHOR]

The African continent is endowed with massive energy resources such as hydropower, solar, wind, natural gas, wave energy, and many more, yet it is the continent with the least energy supply in the world thereby resulting in a lack of sufficient energy to meet its growing energy demand. Though the continent holds 100 GW of wind capabilities, the current installed capacity as at 2018 was 5.7 GW with countries in northern Africa as well as South Africa capturing over 90% of the wind energy share on the continent. Therefore, this paper reviews the wind energy industry in Africa by identifying the current installed and potential capacity of wind energy on the continent. The challenges faced by the wind energy industry such as policy, competition, technical and economic are also reviewed. Transitions, technological innovation systems, and strategic niche management theoretical sustainability transition framework as well as proposed pathways to overcome these prevailing challenges hindering the full exploration of the wind energy sector in Africa are also highlighted in order to uplift the continent's socio-economic status. Basically, this can be achieved through the adoption of strong 'political-will' by African national governments to drive wind energy development. There is also the need for institutional frameworks to ensure the practical adoption of new wind energy technologies. Furthermore, the major benefits Africa stands to gain from investment in wind energy are enumerated by comparing with the benefits realized by other countries' economies as a result of investing in the wind energy industry. For instance, cheap electricity, job creation, industrial growth, and eco-friendly energy source. • Reviewing wind energy industry in Africa and existing challenges. • The challenges faced by African's wind energy industry can be categorized under policy, competition, technical and economic. • Framework for transiting Africa's wind energy industry from small-scale production to large-scale commercial industry.. [ABSTRACT FROM AUTHOR]

Abstract Propelled by the actual demand from the renewable energy industry, the progress of literature on quantitative forecasting models during the past years is extensive. Research provides a vast output of papers on wind speed, wind power, solar irradiance and solar power forecasting models, accompanied by models for energy load and price forecasting for short-term (e.g. for the intraday trading schemes available at many market places) to medium-term (e.g. for day-ahead trading) usage. While the models themselves are, mostly, rather sophisticated, the statistical evaluation of the results sometimes leaves headroom for improvement. Unfortunately, the latter may occasionally result in the rejection of papers. This review aims at giving support at this point: It provides a guide on how to avoid typical mistakes of presenting and evaluating the results of forecasting models. The best practice of forecasting accuracy evaluation, benchmarking, and graphically/tabularly presenting forecasting results is shown. We discuss techniques, examples, guide to a set of paragon papers, and clarify on a state-of-the-art minimum standard of proceeding with the submission of renewable energy forecasting research papers. Highlights • We provide a baseline for the empirical assessment of renewable energy forecasting. • Prices, wind speed/power solar irradiance or price and load forecasts are covered. • We show how to present and evaluate forecasting results. • Performing and evaluating OOS studies and probabilistic forecasts is shown. [ABSTRACT FROM AUTHOR]

Abstract Blue Growth is the creation of economic activity and jobs at sea, while multiple use of space makes efficient use of the available sea area by combining industries. Clearly there are many combinations and many value propositions. However, most technologies to date are considered blue sky concepts, with little robust techno-economic analysis demonstrating profitability. The paper begins by providing a comprehensive review of Blue Growth and multi-use in Blue Growth; both in policy as well as the wide range of current technologies, including ocean energy, offshore wind energy, offshore aquaculture and desalination. The Maribe H2020 project provides the vehicle for the research element of the paper. The major contribution is a new methodology for selecting, filtering, developing and ranking business propositions for multiple-use of space (MUS) and multi-use platforms (MUP). Application of the method for the first time identified three case studies where Blue Growth combination projects can be economically viable, with attractive internal rate of return (IRRs). Results presented for the case studies report standard investment metrics and show the relative contribution of each product (energy, food, water) to the system profitability, as well as socio-economic impact. Existing companies were fully engaged in the process. Co-creation between sector experts and industry led to both improved business value propositions and robust assessment of investment readiness. In contrast to the presumption that large scale platforms are commercially attractive, the highest ranking case study companies required smaller capital expenditure (CAPEX) and operated in niche subsectors. In conclusion, the positive economic performance of the case studies should provide confidence for the EC as well as investors that MUS and MUP have viable economic futures leading towards commercialisation. The macro and micro assessment methods will be particularly useful in other Blue Economy contexts and in other multiple product contexts. Highlights • A comprehensive history of multiple use of space blue growth. • New metrics for comparing salmon to megawatts are presented. • Method and criteria for ranking potential investments in blue growth business models. • Profitable case studies described involving electricity, water, mussels and fish. [ABSTRACT FROM AUTHOR]

Abstract The capacity of installed wind power is growing rapidly in cold climate regions; however, turbine blades are susceptible to ice accumulation. The aerodynamic properties of turbine blades are highly sensitive to ice accretion, which can significantly impair aerodynamic performance. Ice accretion on the blades of a wind turbine can lead to turbine shutdown, power loss and damage to turbine components. To prevent ice formation on wind turbine blades, an ice sensor integrated with an ice mitigation system is required. The ice sensor can be used with a de-icer on the blade surface. However, the current ice sensing and de-icing technologies are inefficient and integrated systems need appreciable improvement. This paper reviews ice sensing and active mitigation techniques for a wind turbine blade surface, which are categorized based on several key parameters. Furthermore, this paper investigates the conceptual design of integrating ice sensing and mitigation systems. The advantages and disadvantages of the integrated systems are presented to provide valuable insights on ice prevention for wind turbines operating in ice prone locations. Highlights • Ice sensing and active mitigation techniques for a wind turbine blade surface. • Review of conceptual designs of integrating ice sensing and mitigation. • Thorough review of advantages and disadvantages of integrated systems. [ABSTRACT FROM AUTHOR]

Abstract The demand for reduction of greenhouse gases, the need for a decreased dependence on fossil fuel, and the increasing penetration of the renewable energy sources are changing the world's electrical energy production. The island of Crete in Greece possesses great potential when it comes to wind and solar energy. Currently, a large amount of wind energy is often being curtailed in Crete, due to the technical minima of the existing thermal units, the inherent fluctuating power output of the wind turbines and the electricity demand profile. Electrical energy storage is recognized as an underpinning technology to have great potential in overcoming these challenges. There are many different ways to store the surplus energy and convert it back to electrical energy when it is needed. The aim of the present paper is the investigation of the role that energy storage can play in the further development of renewable energy sources in non-interconnected islands via considering the energy storage technologies of compressed air energy storage, pumped hydroelectric storage and sodium – sulfur batteries. This paper examines the solution of electrical energy storage in curtailment exploitation. A review over the above energy storage technologies is carried out and a comparative analysis is performed for the case study of Crete. Each storage technology is techno-economically evaluated using actual data. Finally, a parallel comparison of the examined storage systems' levelized cost of energy is presented and conclusions are drawn. The compressed air energy storage system appears to be more favorable, having the lowest levelized cost of energy of the examined systems studied at 0.21 €/kWh, while contributing 105.59 GWh of electrical energy to the island's grid per year. For the examined case study, compressed air energy storage system appears to be almost 20% and 50% cheaper in terms of levelized cost of energy in comparison with pumped hydro storage and batteries respectively. Highlights • Review on compressed air energy storage, pumped hydroelectric storage and sodium – sulfur batteries. • Techno-economic comparative analysis of energy storage technologies for the case study of Crete. • Comparative findings on levelized cost of energy of different storage technologies. [ABSTRACT FROM AUTHOR]

Wind development creates a range of economic impacts at different territorial scales and sectors, one of which is the local sector at the rural level. Yet few studies make an in-depth study on the relationship between the implementation of wind farms and rural development. The literature scarcely analyzes the impact of payments to landowners and their potential for revitalizing rural areas above all in areas lacking public property where community wind farms are legally banned. These two circumstances converge in Galicia, a region in the northwest of Spain that currently operates over 3300 MW of wind power. This paper aims to analyze landowner payments and study their role in the rural development of the Galician territory from the perspective of the current regulatory framework. To this end, it uses different quantitative and qualitative methods such as participatory research tools used in the field work and developed for over 10 years. Our work estimates average payments to landowners and the total flow of wind-generated income reaching the rural areas, which was 0.84 million euros in 1999 and 10.1 million in 2015. It also analyzes final wind revenue destinations and identifies several examples of the dynamization of rural areas based on the innovative use of this income. Rural landowners developed very innovative community initiatives triggering local economic revitalization despite the averse current regulatory framework. The paper concludes that a more advantageous regulatory framework could have had a much greater local impact. [ABSTRACT FROM AUTHOR]

This is a discussion on the paper titled “Assessing feed-in tariffs on wind power installation and industry development in Taiwan” published by Hsu et al. In the discussed paper, there were several missing variables in the historical test of the system dynamics (SD) model, and thus the test was not integrated and valid. Additionally, the simulated results of the missing variables were used as important indexes to observe the behavior of the SD model. Therefore, it was highly likely that the solution and related policy analysis based on the simulated results were incorrect. Accordingly, the present study illustrated the structure characteristics of the SD model with respect to the fore-mentioned problems, discussed the reason for missing variables and proposed a method to assess whether or not the historical test was integrated. Finally, after a careful analysis, this study offered suggestions to perfect the historical test proposed in the discussed paper. [ABSTRACT FROM AUTHOR]

Electrical energy becomes necessary for human being. Generation of electrical energy mostly depends on fossils fuel, they are limited in nature and also responsible for environmental pollution. Renewable energy resources provides a better alternative for future,In comparison to conventional energy resources economical aspect is a major issue of renewable energy sources with the feasibility and efficiency. These limitations are tried to overcome by deployment hybrid renewable energy resources. There are certain criteria to analyze and implement the sized, optimized and cost efficient system. This paper focus on hybrid energy systems based on solar photovoltaic (PV) and wind resources. This paper shed lights on various parameters of economic feasibility, sizing strategies with logical advancements to enhance their utilization, future prospects, and their arrangement. Strategies to develop an effective storage system is also presented here.A brief review on developments in optimization techniques, reliability index and cost analyzing techniques for hybrid renewable energy systems are also presented. [ABSTRACT FROM AUTHOR]

The combination of multilevel inverter with renewable energy source power generation is paid more attention among the researchers, because multilevel inverters are widely accepted power converters in for high-power applications. The conventional multilevel inverters are highly implemented in industries, and the success of this has motivated to create newer topologies with the reduced overall power electronics components. In this paper, recent multilevel inverter topologies with reduced number of switches are taken into account and to find a suitable topology for photovoltaic (PV) and wind energy applications. Finally, this paper gives a pathway for the upcoming researchers to consider the design issues and challenges in the development of new multilevel inverter topologies. [ABSTRACT FROM AUTHOR]

Recently China's wind power industry is challenged by many problems such as wind power integration and wind curtailment, which seriously hinders the development of onshore wind power. Since China's policy has a direct and significant influence on wind power industry, it is vital to analyze and evaluate published policies. This paper explores in detail 134 China's onshore wind power policies from 2005 to 2015 so as to provide analytical support for future formulation and implementation of wind power policy. Based on policy summary from equipment manufacturing industry, wind farms and power grid industry, this paper evaluates the policies from the perspective of overall plan, support policy and policy implementation using fitting method, game theory and empirical analysis. The results indicate that China's wind policy is gradually becoming perfected, for example, there are more reasonable objectives and improved support policies. However, many problems remain to be solved, like unreasonable planning, imperfect support policies, immature trading systems and uncoordinated actions among interest related parties. Furthermore, combined with international experiences, suggestions on improving China's wind power policy are proposed from seven aspects. [ABSTRACT FROM AUTHOR]

The multilevel converter, (MC) had been recommended for high- and medium-level power applications for decades. It is one of the most popular converters due to its ability to decrease the harmonic distortion in the output waveform without decreasing the converter power output. This paper presents the basic concept of four different types of multilevel converter: the neutral-point clamped, flying capacitor, cascaded H-bridge and modular. This paper also reviews five different modulation techniques for multilevel converters: pulse width modulation, space vector pulse width modulation, phase shifted carrier pulse width modulation, sinusoidal pulse width modulation and selective harmonic elimination pulse width modulation. In addition, recent publications regarding developments and improvements of fundamental concern to MCs and modulation techniques are reviewed in this paper. The implementation of MCs within renewable energy systems is also discussed here. [ABSTRACT FROM AUTHOR]

Contemporary electrical networks are moving towards distributed electricity production via the implementation of renewable energy sources. One of the most developed renewable technologies comprises the transformation of the wind's kinetic energy to electrical energy by using wind power converters. However, wind power production is highly dependent on the weather conditions and specifically the available wind resource of an area. Intermittent electricity production of wind turbines hinders their further integration in electricity networks suggesting among other solutions, the implementation of energy storage configurations in order to cope with their stochastic operation. Based on an extensive literature review, this study reveals the potential future role of hydrogen as a multifunctional storage application for wind power. The analyses are carried out to identify the focus of recent studies on coupled wind and hydrogen systems in order to define the potential of such systems and predict the future collaboration between the two technologies. Based on the results, it can be derived that research on wind-hydrogen systems is shifting focus from solely applying hydrogen as a storage application to exporting hydrogen as a bi-product to improve wind power investments. Furthermore, the outcome shows that there is an increasing interest in using wind power generation to produce hydrogen as an end product designed specifically for transportation purposes, while contributing simultaneously to a more sustainable energy mix. This paper provides an ultimate overview of wind-hydrogen systems, which reveals the development as well as the state-of-art of such system's applicability in connection to its changing efficiency. • Wind power coupled to water electrolysis systems was reviewed. • Analysis of pilot and simulated grid-connected wind-hydrogen systems was performed. • Wind-hydrogen coupled systems can support autonomous electric networks. • Wind power-based hydrogen systems can mitigate CO 2 emissions significantly. • Levelised cost of wind-based hydrogen production ranges between 0.3 and 26.6 €/kg H2. [ABSTRACT FROM AUTHOR]

In the context of carbon neutrality, renewable energy, especially wind power, solar PV and hydropower, will become the most important power sources in the future low-carbon power system. Since wind power and solar PV are specifically intermittent and space-heterogeneity, an assessment of renewable energy potential considering the variability of wind power and solar PV with high temporal resolution in different regions will facilitate more accurate identification of the decarbonization pathway of power system. In this paper, the complementary output potential of wind-solar-hydro power every 15 min in 31 Chinese provinces is evaluated by developing a multi-objective optimization model based on Nondominated Sorting Genetic Algorithm II. The results show that the total annual complementary power generation potential in China is 17.57 PWh, of which the three components account for 47.8%, 25.3% and 26.9%, respectively. Inner Mongolia and Tibet are the major renewable energy source provinces with annual complementary power generation potential of 5330 TWh and 3907 TWh, accounting for 30.3% and 13.7% of the total power generation potential, respectively. The temporal potential of wind-solar-hydro power varies greatly, with daily potential is more volatile than monthly. Seasonal and spatial heterogeneity of the complemental renewable potential makes some provinces suffer power shortage during long-hours period especially in winter. Our findings will encourage a higher penetration of renewable energy, the promotion of multi-energy complementarity, and the development of inter-provincial power transmission and energy storage infrastructure in China's future power sector. • A multi-objective wind-solar-hydro complementary optimization model is developed. • Electricity supply and demand have gaps at different temporal and spatial scales. • Wind-solar-hydro complementary potential shows great temporal and spatial variation. • Renewable complementarity can improve China's future power system stability. [ABSTRACT FROM AUTHOR]

The determination of maintenance strategies is subject to complexity and uncertainty arising from variable offshore wind farm states and inaccuracies in model parameters. The most common method in the existing studies is to adopt an open-loop approach to optimize a maintenance strategy. However, this approach lacks the ability to capture periodic operational state of the wind farm and the awareness of eliminating uncertainty. Consequently, the determined strategy is inadequate to instruct maintenance activities, inducing excessive revenue losses. In this paper, a closed-loop maintenance strategy optimization method is proposed for decision-makers to identify a more profitable manner of wind farm maintenance management. The life-cycle maintenance optimization problem is decomposed into a sequence of sub-optimization problems covering multiple time periods by using a rolling-horizon approach. Each sub-optimization problem is intentionally designed based on the monitored state of the wind farm and the available reliability, availability, and maintainability (RAM) database. Meanwhile, the decision maker consciously mitigates the parameter uncertainty in the maintenance model gradually by updating the current database. Compared to conventional strategies covering the entire lifetime of wind farms, the proposed maintenance strategy is periodically adjusted to provide a series of sub-strategies. The proposed approach was applied in a simulation experiment, a generic small-scale offshore wind farm, to assess its performance. Computational results show that adapting maintenance strategies based on the current state of the wind farm can reduce revenue losses in comparison to conventional open-loop strategies. In addition, the benefits of updating the RAM database in decreasing revenue losses is revealed. • Proposing a maintenance strategy with a closed-loop decision-making process. • Dividing the entire maintenance optimization problem into sub-problems covering multiple time periods. • Gradually mitigating model parameter uncertainty over time with new operational data. • Adjusting the entire maintenance strategy into a series of sub-strategies based on wind farm states and updated parameters. [ABSTRACT FROM AUTHOR]

Renewable energy sources such as wind farms and solar power plants are replacing conventional coal-based synchronous generators (SGs) to achieve net-zero carbon emissions worldwide. SGs play an important role in enhancing system strength in a power system to make it more stable during voltage/frequency disruptions. However, traditional coal-fired SGs are being decommissioned in many parts of the world, owing to stringent environmental regulations and low levelized cost of energy of renewables. Consequently, maintaining system strength in a renewable energy-dominated power system has become a major challenge, and without adequate mitigation techniques, low system strength can potentially cause widespread power outages. This paper provides an overview of system strength and its measurement techniques in a power system with a large number of renewable energy sources (RESs), for example solar and wind farms. The review includes the system strength measurement techniques, mitigation approaches, and future challenges. • A comprehensive review on system strength for Australia. • Integration of power systems with large number of renewable energy sources. • Measurement and mitigation techniques for system strength shortfalls. • Analysis of future challenges and research directions on system strength. [ABSTRACT FROM AUTHOR]

The topic of energy islands is currently a focal point in the push for the energy transition. An ambitious project in the North Sea aims to build an offshore wind-powered electrolyser for green hydrogen production. Power-to-X (PtX) is a process of converting renewable electricity into hydrogen-based energy carriers, such as natural gas, liquid fuels and chemicals. PtH2 represents a subset of PtX, wherein hydrogen is the resultant green energy from the conversion process. Many uncertainties surround PtH2 plants, affecting the economic success of the investment and making the price of hydrogen and the levelized cost of hydrogen (LCOH) of this technology uncompetitive. Several studies have analysed PtH 2 layouts to identify the hydrogen price without considering how component capacities and external inputs affect the breakeven price. Unlike previous works, this paper investigates component capacity dependencies under variables such as wind and hydrogen demand shape for dedicated/non-dedicated system layouts. To this end, the techno-economic analysis finds the breakeven price, optimising the components to reach the lowest selling price. Results show that the hydrogen price can reach 2.2 €/kg for a non-dedicated system for certain combinations of maximum demand and electrolyser capacity. Furthermore, the LCOH analysis revealed that the offshore wind electrolyser system is currently uncompetitive with hydrogen production from carbon-based technologies but is competitive with renewable technologies. The sensitivity analysis reveals the green electricity price in the non-dedicated case for which a dedicated system has a lower optimum hydrogen price. The price limit for the dedicated case is 116 €/MWh. [Display omitted] • Dependencies among hydrogen tank, offshore, electrolyser and demand were identified. • The price of hydrogen for energy islands can reach 2.2 €/kg. • LCOH from offshore is competitive with renewable technologies. • Offshore electricity price will play a role in the energy island system layout. [ABSTRACT FROM AUTHOR]

Using floating platforms to support offshore wind turbines will be necessary for many countries to reach their Net-Zero targets, since much of the wind resource is located at water depths at which fixed offshore wind turbines are uneconomic or technologically unfeasible. However, floating platforms for wind turbines are still at an early stage of development, and there are a wide range of platform designs. This paper reviews the current state-of-the-art of floating offshore wind turbine platform designs which currently have or have previously had a prototype, demonstration, or farm scale project at sea. The most common design goals for the platforms and the corresponding design features of platforms used to achieve those goals are reviewed. Past, current and projected future levelized cost of energy values for floating offshore wind are reviewed and discussed. The development of each platform design is described, including evolving design goals and resulting changes in platform features. Finally, overall trends in platform designs are discussed and divided into three phases, defined by changing goals: (i) influences from the offshore oil and gas industry, (ii) specialization to floating offshore wind, and (iii) further specialization to local environment. [Display omitted] • Floating offshore wind turbine platform designs with a device at sea are reviewed. • Common design goals and associated design features of platforms are summarized. • Levelized cost of energy for floating offshore wind turbines is discussed. • Evolution and trends in design drivers and platform designs are summarized. [ABSTRACT FROM AUTHOR]

Government and commercial forecasts indicate global ambitions for 2000 GW of installed offshore wind (OW) by 2050 to meet the targets of the Paris Agreement. Set against a current global installed capacity of 56 GW offshore wind, which has taken over 30 years to achieve, the challenge of installing 35 times that capacity in the coming 30 years is considerable. Aside from the issue of the necessary pace of OW installation, another challenge is scale: Where in the ocean could and should this new infrastructure be placed? This paper presents a spatial analysis approach for assessing the location of future offshore wind that collates and integrates, metocean, geoscience, ecological and anthropogenic features and intersects with engineering requirements. A new contribution to the field is made through calibration in relation to current ocean 'crowdedness', which leads to a suitability ranking of new sea regions. A case study is presented to illustrate the workflow and methodology of this approach based on the United Kingdom (UK)-Economic Exclusive Zone (EEZ). The UK has been selected as an exemplar due to its well-developed offshore wind sector, having the greatest installed capacity globally until the close of 2021, and as a region with ambitious and legislated offshore wind targets to meet net zero. The modelling and analysis quantify the need to eliminate the water depth barrier through floating OW technology, open up new sea regions and the associated port and grid infrastructure, as well as to assess the potential impact of increased utilisation of ocean space for OW. • 34-layer GIS model of UK geoscience, metocean, ecological & anthropogenic features. • Interactive map created to show suitable space for future offshore wind (OW). • Scenarios of OW in each sea region illustrated for various net zero future cases. • Need for co-location, floating OW and development of new sea regions quantified. [ABSTRACT FROM AUTHOR]

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

This paper evaluates the potential of wind energy in six coastal locations in the Kingdom of Morocco, namely Al Hoceima, Tetouane, Assila, Essouira, Laayoune and Dakhla. First, a literature review of recent wind energy potential studies in different locations worldwide has been conducted. Thereafter, the status of wind energy development in Morocco along with its achievements and challenges has been reported. A comprehensive literature review of the mathematical distributions used to fit wind data and procedures employed to estimate the shape and scale parameters of the Weibull distribution is as well presented. The second part of this paper investigated the statistical analysis of wind data based on hourly wind speeds and directions considered for a period of five years between 2011 and 2015. The analysis has shown that the Weibull model independently of the used algorithms for estimation scale and shape parameters, presented an accurate description of the frequencies of actual wind data. By the end, annual energy outputs and capacity factors were derived for wind turbines of various sizes between 225 and 900 kW. The results showed that Dakhla is the most suitable location for harnessing the wind power, while Laayoune has been identified as the second most suitable site. Both Dakhla and Laayoune were found to be suitable for the grid-connected wind energy conversion system while Assila and Essouira have been categorized to be appropriate for the stand-alone wind power applications. [ABSTRACT FROM AUTHOR]

Generation assets applying for grid connection must comply with certain grid code requirements. Grid code compliance verification shall include revision of documentation covering technical data and models, checking of requested capabilities, and validation of model performance. These procedures are singular regarding renewable power generation, due to their technical characteristics, specific topologies and short experience. This paper aims to carry out an updated review of the international regulations and current practices regarding the verification and certification of the electrical performance in renewable generation systems. Grid code compliance can be verified by practical tests or by simulation of validated models. Therefore, this paper also encompasses modelling and validation requirements, highlighting challenges caused by current procedures. [ABSTRACT FROM AUTHOR]

The accurate assessment of the potential wind energy at a define site is very important from economic point of view, measures cost effectiveness of the project and helps estimating future incomes, revenues. Knowledge of wind characteristics also facilitates a proper turbine design selection. There are different techniques for wind energy evaluation. The direct wind speed measurement is the most accurate method to determine wind conditions, but often the different wind speed frequency distributions are proposed. One of the most widely used distribution is Weibull distribution. The two-parameter Weibull distribution is recognized as an appropriate model and the most widely used in the wind industry sector. In some cases, in which the probability of null wind is significant, the Weibull distribution does not reveal good conformity for the low wind speed. In theory, it seems that the three-parameter Weibull distribution, which takes into account the frequency of null winds, may better represent wind ranges with high percentages of null wind speeds and may give better results. In the paper, the review of the literature is carried out on the application of two and three-parameter Weibull distribution in wind energy analyses and also focuses on the comparison of results received from different probability density functions, used in cited papers, with the frequency of 0–2 m/s wind speed range in real data. For higher percentages of null wind speeds or the wind speed below 2 m/s, the three-parameter Weibull model should have the advantage in relation to two-parameter Weibull distribution, gives more appropriate results and can be proposed as an alternative to wind energy estimation technique. [ABSTRACT FROM AUTHOR]

Nowadays, renewable energies are more preferable to fossil fuels because of being free, widely available and producing minimal pollution. One of the disadvantages of renewable energy systems is that using only one type of renewable energy cannot guarantee a continuous power generation. To overcome this problem, two or more renewable energy systems should be used simultaneously to compensate for times when one of them is not available or the renewable system should be used aligned with the generator. In addition, another weakness is that they are not accessible in every geographical position and location. It is clear that renewable energy systems can be exploited to their fullest capacity when used in the proper place. Therefore, given the importance of finding suitable places for co-utilization of several renewable energies, present paper attempted to find the ideal locations for construction of hybrid solar-wind power stations in Middle-East using Boolean model in GIS software. The Boolean method is, in a way, a more stringent method compared to the other positioning methods. Therefore, the selected locations will definitely have greater energy potential by using the Boolean method. Data obtained by RETScreen4 software from 400 stations in Middle-East were used for collecting monthly weather information. Results of the current paper may be helpful in creating prospects for sustainable energy development for systems based on natural resources and facilitating the national power transmission and sustainable environmental policies. [ABSTRACT FROM AUTHOR]

The application of VSC-HVDC (Voltage Source Converter Based High Voltage Direct Current Transmission) is one of the proven solutions to the transmission problems of offshore wind power. As AC and DC networks become more complex, VSC-MTDC (Multi-terminal High Voltage Direct Current Transmission Based on VSC) is developed based on two-terminal HVDC to offer technology support for the accessing among multi-supplier center, multi-loads center and distributed renewable powers. This paper reviews the MTDC and its implementation in China, mainly discusses the topologies of DC network of VSC-MTDC system and the control strategies of VSC-MTDC which includes converter station control and coordinated control. In most cases, double closed-loop space vector control (DCSVC) strategy applied in the Zhoushan project, which includes five-terminals and has been put into operation, is adopted for the converter station control. But the method can not work under the unbalanced voltage situation, thus an improved double closed-loop space vector control strategy, which includes positive and negative sequence components, is proposed in this paper. As for coordinated control, master-slave control, DC voltage droop control and DC voltage margin control are presented. As for the part of implementation of MTDC in China, Zhoushan project is presented in detail. This paper provides good theoretical foundation for the grid integration and the transmission of large offshore wind farms. [ABSTRACT FROM AUTHOR]

Currently, wind energy is one of the most important sources of renewable energy. Offshore locations for wind turbines are increasingly exploited because of their numerous advantages. However, offshore wind farms require high investment in maintenance service. Due to its complexity and special requirements, maintenance service is usually outsourced by wind farm owners. In this paper, we propose a novel approach to determine, quantify, and reduce the possible conflicts of interest between owners and maintenance suppliers. We created a complete techno-economic model to address this problem from an impartial point of view. An iterative process was developed to obtain statistical results that can help stakeholders negotiate the terms of the contract, in which the availability of the wind farm is the reference parameter by which to determine penalisations and incentives. Moreover, a multi-objective programming problem was addressed that maximises the profits of both parties without losing the alignment of their interests. The main scientific contribution of this paper is the maintenance analysis of offshore wind farms from two perspectives: that of the owner and the maintenance supplier. This analysis evaluates the conflicts of interest of both parties. In addition, we demonstrate that proper adjustment of some parameters, such as penalisation, incentives, and resources, and adequate control of availability can help reduce this conflict of interests. • Reliability of OWF analysis for owners and maintenance suppliers. • Consequences of outsourced maintenance for owners and maintenance suppliers. • Costs and profits analysis of OWF owners and maintenance suppliers. • A novel approach to reduce the conflict of interests between both parties. [ABSTRACT FROM AUTHOR]

Reliable and efficient power modeling from meteorological wind data is vital for optimal implementation and monitoring of wind energy, and it is important for understanding turbine control, farm operational optimization, and grid load balance. Based on the idea that similar wind conditions lead to similar wind powers; this paper constructs a modeling scheme that orderly integrates three types of ensemble learning algorithms—bagging, boosting, and stacking—and clustering approaches to achieve wind power modeling from multiple wind-based meteorological factors in a wind farm. The paper also investigates the applications of different clustering algorithms and methodologies to determine cluster numbers in the modeling. The results reveal that all ensemble models with clustering exploit the intrinsic information in wind data and thus outperform models without clustering by approximately 15% on average in modeling wind power. The model with the best-performing Farthest First clustering is computationally rapid and with an improvement of around 30% compared with the baselines. Given the diversity introduced by clustering algorithms, the power modeling performance is further boosted by about 5% by introducing stacking that fuses ensembles with varying clusters. The proposed modeling framework thus demonstrates promise by delivering efficient and robust performance on the targeted problem. • Systematic demonstration of wind power modeling from weather data. • Construction and comparison of various clustering methods for classifying wind data. • Combination of bagging, boosting, and stacking for modeling. • Multiple wind meteorological characteristics are considered in the modeling. [ABSTRACT FROM AUTHOR]

A method for assessing and mapping the wind energy potential of near- and off-shore areas by means of multi sensor satellites (i.e. the recently launched Sentinel 1) is shown in this paper and applied to a case study area in the north-west coast of the Sicily island. The presented method aims at i) preliminary identifying the best sites for wind turbine generators installation and/or ii) estimating the average wind potential in small areas (e.g. archipelagos) for energy planning purposes. Firstly, a detailed literature review of existing techniques for wind speed estimation has been carried out, considering the most traditional methods (e.g. meteorological masts), remote sensing techniques and including a thorough review on the use of Synthetic Aperture Radar (SAR) methods integrated with Geophysical Model Functions (GMFs) for wind speed retrieval. This review enables to identify CMOD5 (C Geophysical model function 5) as the best performing GMF overcoming the CMOD4 accuracy issues in high wind speed conditions. Thus, the method has been detailly described and showcased through the analysis of the case study. SAR images from the Sentinel 1 satellite have been processed by means of the Sentinel Application Platform (SNAP) software. Afterwards, the wind speed and direction have been mapped through a Geographic Information System software. Lastly, the mean wind climate has been extrapolated for a specific Region Of Interest by the Environment for Visualizing Images (ENVI) 4.8 software. Consequentially, six hot spots characterized by high-energy potential have been identified as possible sites for possible installations of wind turbine generators. • A detailed literature review of techniques for wind speed assessment is provided. • An integrated methodology for wind speed assessment and mapping is presented. • Wind speed retrieval from C-band Sentinel1 SAR images by means of the SNAP software. • Wind speed mapping through the ArcGIS/ENVI software. [ABSTRACT FROM AUTHOR]

South Korea's new energy transition policy was declared in 2017 as citizen demand grew for solutions to safety problems caused by successive earthquakes affecting areas with many nuclear power plants in 2016 and 2017 as well as health problems caused by coal-fired power plants contributing to high condensable particulate matter in spring. This policy focuses on both a reduction in nuclear and coal-fired power plants and further development of eco-friendly and sustainable power generation and supply. The South Korean government is thus planning a large-scale transition toward improved energy efficiency as well as safe and clean energy sources. Its announced goal is to supply a 20% share of renewable energy in the national energy mix, including 37 GW of photovoltaic power, 3 GW of onshore wind power, and 13 GW of offshore wind power by 2030; the latter is expected to play a strategic role in the Renewable Energy 2030 plan. As South Korea's geographic conditions enable large-scale offshore wind farm projects that are relatively free from complaints and visual effects caused by transportation, installation, noise, vibration, and damage to natural environments, it is highly likely that wind power will become one of the nation's major renewable electricity sources. This paper discusses the potential for developing offshore wind farm projects in South Korea with particular focus on analyzing offshore resources and reviewing government policies and support programs that could limit or otherwise challenge the deployment of such projects, with further considerations of policy choices that could improve the deployment of offshore wind power. As the greatest hindrances to offshore wind power development are frequently-changed government policies and support programs, the adoption of consistent, stable, and efficient guidelines and supports would be most beneficial for meeting South Korea's goals of increased offshore wind energy supplies. • A broader approach to analyze the S. Korea's offshore wind energy policy, regulatory frameworks, supports and supply chain. • An overview of the offshore wind energy potentials and the current projects in South Korea. • Identifies the key barriers faced by the offshore wind energy industry. • Emphasizes the importance of the government's policy development to achieve the offshore wind power deployment target. [ABSTRACT FROM AUTHOR]

Offshore wind energy is recognised globally as a viable alternative to finite energy sources. However, large cost reductions are still needed, particularly in the Operations & Maintenance (O&M) phase, which currently accounts for about 30% of the cost of offshore wind. For large component replacements, a jack-up vessel is often leased from the spot market, resulting in high costs and low utilisation. These costs can be lowered when multiple wind farm service providers would share the resources needed to employ jack-up vessels. In this paper, we analyse two types of resource sharing, as an alternative to each service provider leasing its own vessel: (i) vessel purchasing and sharing and (ii) the combined use of vessel and harbour sharing. We design a simulation model and include stochastic processes such as weather patterns and component failures. Results show that cost benefits up to 45% can be achieved compared to a leasing policy, depending on the number of wind farm service providers involved and on the geographical distance between offshore wind farms. Moreover, it is shown that the jack-up vessel should not be fully utilised to minimise costs. The performance benefits of harbour sharing in addition to vessel sharing are generally small, but become more significant if the network faces considerable congestion. Results are illustrated using a case study based on a setting in the Western North Sea. • Three policies are studied for the deployment of jack-up vessels for o_shore wind farm maintenance. • Collaboratively purchasing and sharing a jack-up vessel outperforms individually leasing it. • Adding harbour facility sharing among operators only leads to slightly further cost reductions. • Operators should not focus on high jack-up utilisation as this results in unnecessarily high costs. • Yearly cost and the best coalition size are particularly sensitive to the replacement time and failure rate of the gearbox. [ABSTRACT FROM AUTHOR]

Abstract Wind speed and power forecast is an essential component to ensure grid stability and reliability. The traditional forecasting methods fail to address the non-linearity in the wind speed time-series, thus paving way for machine intelligent algorithms. This paper discusses a hybrid machine intelligent wind forecasting model utilizing different variants of Support Vector Regression (SVR) built on wavelet transform. Various performance indices are evaluated to identify the possible best one among four different machine learning regressors for wind forecasting application. Apart from standard ε-SVR and LS-SVR, two new regression models, namely, ε-Twin Support vector regression (ε-TSVR) and Twin Support vector regression (TSVR) are used to forecast short-term wind speed, and are compared with Persistence model for four wind farm sites. The effect of larger dataset on forecasting performance is evaluated for two wind farm sites from USA and India. Further, wind power ramp events are investigated at different hub heights and the forecasting performance of different variants of SVR is compared for five wind farm sites. Highlights • Machine intelligent SVR variants are discussed for short-term wind forecasting. • Overfitting and underfitting scenarios of variants of SVR are assessed. • Forecasting performance of SVR variants is assessed during wind power ramp event. • Wind power ramp events are analyzed at different hub heights for 5 wind farm sites. [ABSTRACT FROM AUTHOR]

Abstract Subsynchronous control interaction (SSCI) associated with wind farms has become one of the major challenges for maintaining the stability and reliability of modern power systems. SSCI is mainly caused by the active participation of fast-acting wind turbine converter (WTC) controls in the phenomenon. It can damage the system equipment, reduce the amount of power generation, and degrade the power quality. Thus, it is urgent to develop practical mitigation techniques for the SSCI in order to achieve a smooth and reliable operation of grid interfaced wind farms. This study presents an overview of potential SSCI mitigation techniques at various stages of the power system, including system planning, operation, control, and protection phases at both network and generation sides. In particular, this paper reviews the active damping controls utilizing flexible ac transmission systems (FACTS) and WTC controls. Finally, it outlines the challenges and future work in studying SSCI mitigation techniques in practical wind power systems. Highlights • SSCI mitigation techniques: planning, operation, control and protection stages. • Review of active damping control techniques in network and generation sides. • Challenges and limitations of various SSCI mitigation techniques are discussed. • WTC control modifications and shunt-VSC using filters are recommended approaches. [ABSTRACT FROM AUTHOR]

Abstract Blue energy is one of the development sectors identified in the European Union strategic documents within the blue economy that promotes the exploitation of the sea potential. European energy initiatives recognize the importance of blue energy and encourage its research and development. The offshore exploitation of hydrocarbons worldwide is entering the final phase, followed by the gradual decommissioning of the production platforms and their removal. Decommissioning usually has an adverse effect on the environment aside from its economic intensity. By proper planning, lifetime of existing offshore infrastructure can be extended as it can be used for blue energy or other activities related to the blue economy. The paper deals with preliminary assessment of natural gas offshore infrastructure applicability for various blue energy options such as the wind power for electricity generation along with hydrogen, methane or ammonia production and other uses to reduce waste, energy consumption and CO 2 emissions. Methods used included data gathering from 19 offshore gas facilities including assessment of natural gas production on current offshore fields, reserves and technology use, wind potential and decommissioning. Review of potential for energy production, storage and other activities such as CCS and CCU have also been given. Preliminary results show that there are possibilities for feasible and environmentally friendly blue energy utilisation. Average calculated capacity factors for the wind turbines are at the 32%. To investigate economic feasibility of decommission delay, detailed data gathering of wind potential should be done at specific heights along with load capacity of the gas platforms. Highlights • Offshore oil and gas platforms could be reutilised after production. • Wind energy utilisation is the most promising option for blue energy production. • Rather than removed, offshore rigs could be converted into artificial reefs. [ABSTRACT FROM AUTHOR]

Abstract Pumping of water requires excessive energy for its operation by consuming a massive amount of diesel, gasoline, electric power etc. The more promising alternative energies to perform the same operation without any energy cost are solar photovoltaic (PV) and wind. These fastest growing renewable energies are more reliable and well suitable for remote villages where there is no possibility of extending transmission lines. Furthermore, these systems are optimal for conditions like only small amount of water needed to be pumped for a particular time. Unlike conventional energy sources of electric power, the renewable energy sources are not dispatchable its power output cannot be controlled. In that case, it involves power conversion stages so that it would necessitate to design an advanced control strategy technique. Those control strategies greatly avoid and protects the system from detrimental operating conditions by monitoring input voltage, water flow, torque, power, pressure, speed and motor vibration etc. Henceforth the use of efficient control strategy not only increase the performance of system it also helps to increase the number of operational hours of solar PV and wind energy systems. In this manuscript, the research work of various control strategies carried out in solar PV and wind energy-based water pumping systems are presented. Additionally, this paper intends to discuss the energy management strategies applied for renewable energy fed water pumping system when the system assisted with third energy system (battery bank, fuel cell, etc). These benefited systems ensure good design, guarantees the control speed required for the motor, regulates the flow of water, assuring accurate operation for all conversion and finally, it maintains precise balance in between the renewable energy generated and power required by the load (pump). Highlights • The cost of water pumped by solar PV or wind is lower than the diesel systems along with the avoidance of CO 2 emissions. • In solar PV fed water pumping system the selection of suitable PV material with new technology will have great impacts on the reliability and performance of systems. This may also reduce the utilization of number of PV modules. • When looking for a simple solar PV fed water pumping system without any control unit complexity DC motors are much preferable. However, for submersible applications the regular maintenance of replacing brushes makes it to be unfit for it. • The finest power matching between the wind turbine and water pump must be ensured with generator and motor specification because the mismatch may lead to give poor overall efficiency along with degradation in rotor speed range. • The development on single stage power conversion stage for hybrid systems are needed to reduce complexity and to increase the efficiency of system. [ABSTRACT FROM AUTHOR]

Abstract This paper evaluates the potential for co-location of offshore wind turbines at sites being developed for tidal stream arrays as a method for reducing the cost of electricity. It is shown that for a typical tidal site, MeyGen in the Pentland Firth, UK, increasing the wind turbine capacity reduces the cost of electricity compared to operating tidal stream arrays alone. This is due to increased energy yield combined with reduction of capital expenditure based on the use of common grid connection and shared support structures. Assessment is made using tidal, wave and wind resource data for a three year period. The overturning moment about the base of a monopile supporting a wind turbine with two tidal turbines is only 8% larger than for a wind turbine alone in a strong current typical of tidal farms. The increased cost of infrastructure is small relative to the increased energy yield and for all array configurations of practical interest, the levelised capital cost of energy is estimated to be 10–12% less from a co-located farm than from a tidal turbine farm alone. Highlights • Cost of electricity by co-locating wind turbines with tidal stream arrays is evaluated. • Energy yield and peak loads are modelled for array layouts in the Pentland Firth. • Peak loads for a shared support are 60% greater than typical offshore wind turbines. • For the same cost, co-location generates 20% more yield than tidal-only arrays. • Co-location offers 10–12% lower levelised cost compared to a comparable tidal array. [ABSTRACT FROM AUTHOR]

Abstract Offshore wind is a source of clean, renewable energy of great potential value to the power industry in the context of a low carbon society. Rapid development of offshore wind energy depends on a good understanding of technical issues related to offshore wind turbines, which is spurring ongoing research and development programmes. Foundations of offshore wind turbines present one of the main challenges in offshore wind turbine design. This paper reviews the present state of knowledge concerning geotechnical and structural issues affecting foundation types under consideration for the support structures of offshore wind turbines, and provides recommendations for future research and development. Highlights • Reviews the technology development and designs of offshore wind turbine foundations. • Discusses geotechnical and structural issues affecting the foundations. • Provides recommendations for future R&D to improve the effectiveness of different designs. [ABSTRACT FROM AUTHOR]

Abstract The paper investigates the construction of strategies aiming to up-scale low-carbon innovations from pilot to full commercial scale. This requires a systemic understanding of the evolution of the technology along with the organizations and infrastructures supporting its development. Technological innovation systems concepts operationalize system building processes, including the establishment of constituent elements and the performance of key innovation activities. The study surveys the national roadmaps published between 2009 and 2014 for offshore wind energy in deepwaters (more than 50 m deep) which inform on how actors expect the system to grow, including the innovation activities crucial to achieve it. The roadmaps point to the role of guidance and legitimacy as triggers of changes in other innovation processes (knowledge creation, experimentation and so on) needed for take-off. The analysis reveals that the growth plans conveyed in the roadmaps are overly optimistic when compared with the time taken to develop offshore wind energy in fixed structures for shallow waters. Several countries have adopted supporting policies following the publication of the roadmaps, but weaknesses in crucial innovation processes (e.g. specialized skills) and external factors (e.g. crisis, regulatory approval) resulted in a delay of the first large investments. Policy should be based on realistic expectations and adequate to the phase of innovation, such as the promotion of technology-specific institutions (standards, codes, regulations and so on) in technology up-scaling. New directions for research are also provided. Highlights • Emerging energy innovation systems need scaling up demonstrators and markets. • Up-scaling involves changes at technological and institutional levels. • 10 proposals for the development of floating offshore wind energy are surveyed. • Visions and strategies converge for accelerating diffusion take-up. • Larger scale projects but also regulation and codes required for system up-scaling. [ABSTRACT FROM AUTHOR]

Abstract Owing to the wind and photovoltaic (PV) potential in Brazil, the country has recently seen increased exploration into the construction of wind-PV hybrid plants. However, as specific criteria for contracting this type of project have not yet been developed, this paper presents a model to assist the government in contracting projects that maximize the socioeconomic well-being of the Brazilian electricity sector. For this, multiobjective programming is used to simultaneously handle two objective functions—maximally reducing emission density and minimizing the levelized cost of electricity (LCOE)—with the aid of the mixture arrangement technique. In this respect, the optimization method called normal boundary intersection (NBI) is applied to solve the multiobjective problem and construct the Pareto frontier. Additionally, a metric based on the ratio between entropy and the global percentage error (GPE) is used to identify the optimal Pareto solution. The model was applied to determine optimal configurations for wind-PV powerplants in twelve Brazilian cities, and the results obtained reveal the capacity of the model to indicate the optimum configuration according to the wind and PV potential of each city. Highlights • The use of renewable energy sources has been encouraged in Brazil. • The construction of PV-wind hybrid plants has been recently explored. • Normal Boundary Intersection is used to simultaneously handle two objective functions. • Reduced emission density and LCOE were optimized in twelve Brazilian cities. • Results reveal the capacity of the model to indicate the plants optimum configuration. [ABSTRACT FROM AUTHOR]

Abstract The focus of this paper is to analyse the determinants of wind energy development in the United States and how procedural and regulatory frameworks influence the deployment of wind power facilities. The empirical analysis uses statistical regression models integrating geospatial, macroeconomic and socio-environmental control variables. Using wind penetration as well as wind capacity additions as dependent variable permits a more differentiated analysis of both absolute and relative growth factors. This enables a precise assessment of state-to-state variations in permitting, zoning and siting procedures that wind developers have to clear before being authorised to start construction. Quantifying the number of state-level financial support measures and various permitting and regulatory process stages allowed for a more comprehensive assessment of administrative barriers to wind energy development than prior research studies. The results indicate a partial reversal of previous findings that showed that a high quantity of state-level regulations negatively affects wind capacity additions. Exogenous factors such as the ratio of in-state federal lands, population density, and especially wind energy potential, as well as federal statutes and incentives remain the main drivers of wind capacity additions and overall wind energy penetration. Contrasting prior literature, the influence of localised financial incentives or regulatory approval procedures appears to be minor; therefore streamlining national policies and incentives at the federal level might prove more effective than promoting wind development at the state level. We point out that future research should also examine the role of quality of state-level regulations in addition to quantity. Highlights • Most up-to-date United States state-level study using recent data sets from 2010 to 2016. • Number of financial incentives & regulatory measures are weak growth indicators. • Overall wind potential is the strongest driver of wind development. • Novel dependent variable for wind penetration enables relative growth analysis. • Quantity of environmental regulations did not influence energy growth. [ABSTRACT FROM AUTHOR]

Solar and wind energy are considered as promising electrical generating sources. These renewable energies are omnipresent, with free access, and a friendly environmental impact. Their integration remains technically and economically advantageous for electrical generation in isolated areas (IS). In several cases, the separate use of solar and wind energy sources may result in considerable over-sizing, which makes the single renewable energy sources in implementation very costly. It is found that the use of one of the optimization sizing techniques could help to guarantee the maximum power reliability and the minimum system cost for the future hybrid implementation. Moreover, a remarkable interest is manifesting for the use of solar and wind renewable energy sources (RES), which provide a realistic form of electrical generation in isolated areas. This paper provides an updated literature review, of the most applied method and techniques used in sizing and optimization of PV-Wind based hybrid system (PWHS) for an isolated area aiming to reach the best compromise between power reliability and hybrid system costs. Furthermore, this work discusses a comparison of the most common topologies used for the implementation of PWHS, then, presents a mathematical model of the hybrid system components with an emphasis on the importance of power reliability and system cost, Finally, provides an extensive analysis of software tools and algorithm approach used in sizing optimization. [ABSTRACT FROM AUTHOR]

Recent increases in the global demand for IT services have increased the power consumption, total ownership costs and environmental footprint of data centers. Recent efforts to reduce these effects have focused on either their cooling systems, or their power systems. In this paper, we have developed an integrated approach to minimize the total power demand of data centers, whilst their reliance on power imported from the grid is minimized. First, the power demand of data center has been reduced utilizing various air-side economizer-based cooling systems. Since the effectiveness of economizers significantly depends on the local weather conditions, 42 stations in major cities across the world have been considered. A more than 80% reduction in total cooling power consumption is achieved by using the most appropriate air-side economizer at each location. Second, the reliance of data centers on power imported from the grid is minimized utilizing on-site hybrid renewable power generation and energy storage. The on-site renewable power generation and capacity factors have been calculated for 1 MW wind and solar renewable power plants to identify the location with the highest renewable power generation capability. The optimal size of a hybrid renewable power plant, and associated battery energy storage system, is also determined for each data center using linear programming to minimize total levelized costs. Finally, the optimal location for constructing and operating the most energy efficient, cost-effective and sustainable data center has been identified by calculating its level of independence from the power grid. It is found that the level of grid independence increases as we move away from the equator, for example more than 50% grid independence can be achieved at Regina station located in Canada. [ABSTRACT FROM AUTHOR]

Multi-criteria decision making (MCDM) methods are becoming increasingly popular in solving energy selection problems because these problems involve multiple and often conflicting criteria. This paper presents comparative analysis of ranking renewable energy sources (RES) for electricity generation in Taiwan using four MCDM methods - WSM, VIKOR, TOPSIS, and ELECTRE. The Shannon entropy weight method is used to assess the importance of each criterion for the ranking of RES. After that, four MCDM methods are utilized for quantitative evaluation to rank all available RE alternatives. From the weights estimation results, efficiency is the first priority in all evaluation criteria, followed by job creation, operation, and maintenance cost. The purpose of this study is to rank the priorities of various RES and propose recommendations for Taiwan's RE development. The ranking results show that hydro is the best alternative in Taiwan, followed by solar, wind, biomass and geothermal. Furthermore, sensitivity analysis of the weights was conducted considering the ranking results heavily depend on the criteria weight. The results of sensitivity analysis indicated that when financial or technical aspects are focused upon, hydropower is the best RES because its technology is the most mature and the cost is the lowest in Taiwan. In addition, from an environmental perspective, wind energy is the best choice, and from the social perspective, solar PV is the best choice. The findings of this study can provide useful information to energy decision makers and serve as a reference for Taiwan's energy policy. [ABSTRACT FROM AUTHOR]

Due to use of fossil fuels for the human activities found a significant effect on the environment as well as people's health. Hence, the researchers from all around the world are searching for the sustainable solution through non-conventional sources of energy like wind, biomass, solar energy etc. Among all non-conventional sources of energy, solar energy is prevalent. Pasteurisation is a process of heating of food or liquid for the killing of bacteria. For pasteurisation of milk, dairy industries require boiler or heat exchanger, and it consumes energy, and sometimes they need fossil fuels. Hence, a primary aim of this review paper is to discuss various research works have conducted by researchers on milk pasteurisation system so an appropriate best solution can be found for sustainable development. [ABSTRACT FROM AUTHOR]

This paper determines a least cost electricity solution for Sub-Saharan Africa (SSA). The power system discussed in this study is hourly resolved and based on 100% Renewable Energy (RE) technologies. Sub-Saharan Africa was subdivided into 16 sub-regions. Four different scenarios were considered involving the setup of a high voltage direct current (HVDC) transmission grid. An integrated scenario that considers water desalination and industrial gas production was also analyzed. This study reveals that RE is sufficient to cover 866.4 TWh estimated electricity demand for 2030 and additional electricity needed to fulfill 319 million m 3 of water desalination and 268 TWh LHV of synthetic natural gas demand. Existing hydro dams can be used as virtual batteries for solar PV and wind electricity storage, diminishing the role of other storage technologies. The results for total levelised cost of electricity (LCOE) decreases from 57.8 €/MWh for a highly decentralized to 54.7 €/MWh for a more centralized grid scenario. For the integrated scenario, including water desalination and synthetic natural gas demand, the levelised cost of gas and the levelised cost of water are 113.7 €/MWh LHV and 1.39 €/m 3 , respectively. A reduction of 6% in total cost and 19% in electricity generation was realized as a result of integrating desalination and power-to-gas sectors into the system. A review of studies on the energy future of Sub-Saharan Africa provides the basis for a detailed discussion of the new results presented. [ABSTRACT FROM AUTHOR]

The most important single event of the last years in wind energy technology is the reduction in the cost of producing wind electricity offshore, a reduction that can reach 75%, depending on the system boundary considered, for installations commissioned by 2024. Surprisingly, there is very little scientific literature showing how this reduction is being achieved. The objective of this paper is to analyse the evidence behind cost reduction in one of the most significant cost elements of offshore wind farms, the installation of foundations and turbines. This cost is directly dependent on the daily rates of the installation vessels and on the days it takes to install those wind farm elements. Therefore, we collected installation data from 87 wind farms installed from 2000 to 2017, to establish the exact time for installation in each. The results show that advances have reached 70% reduction in installation times throughout the period for the whole set, turbine plus foundation. Most of these improvements (and the corresponding impact in reducing costs) relate to the larger size of turbines installed nowadays. There is, therefore, not any leap forward in the installation process, but only incremental improvements applied to turbines that are now four times as large as in 2000. [ABSTRACT FROM AUTHOR]

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