The micro- and mini-distributed generation (MMDG) has significantly increased after the normative resolution No. 482/2012 in Brazil; the installed capacity surpassed 7 GW in 2021. In the international context, a similar event was observed, whose process generated a cross-subsidy for other consumers, in addition to other problems that affect the economic balance of concessionaires. To mitigate this issue, the National Electric Energy Agency (ANEEL) is in the process of revising current rules. Thus, this study estimates the weight of this decision, through a methodology adapted from international assessment models, based on information from the Brazilian regulatory system. In order to achieve it, this paper presents metrics to define the potential market MMDG, based on the consumption patterns of consumers. Then, through time series analysis, the MMDG demand curve is estimated under two scenarios up to 2030. Finally, the economic impact on tariff adjustments and revisions, and their effe... [more]

The Vietnamese government has decided to use and promote the development of more renewable energy sources, particularly wind energy. When implementing a wind energy project, choosing a wind turbine supplier is an important decision and investors must find the optimal supplier through evaluating many qualitative and quantitative criteria that affect each other symmetrically. Therefore, the process used for selecting a wind turbine supplier in wind power projects is a multi-criteria decision-making process. Many approaches have been applied for this decision process, some of which are based on multicriteria decision-making (MCDM) methods, whether applied individually or in combination with other MCDM models. In this study, the researchers proposed a decision-making model based on spherical fuzzy sets for wind turbine supplier selection in wind power energy projects. In this paper, Vietnam is used as a case study. The recommended turbine suppliers for installations can finally be generate... [more]

Spain has become one of the leading countries in the world in promoting electricity generation from renewable energy sources (RES), due to their positive socioeconomic and environmental impacts, through highly favorable regulatory frameworks and public incentives set by Spanish governments mainly during the first decade of 2000s, i.e., Royal Decree (RD) 2818/1998, RD 436/2004 and RD 661/2007. Conversely, the highly favorable regime applicable to RES, and specifically to solar power plants during the 1998−2008 promotion period turned into an extremely unfavorable scenario during the 2008−2020 cost-containment stage, characterized by the dismantling of the previous promotion schemes so as to reduce the skyrocketing electricity system tariff deficit, in which regulations such as RD 1578/2008, Royal Decree Law (RDL) 6/2009, RDL 14/2010, RDL 1/2012, Law 15/2012, RDL 9/2013, Law 24/2013 and RD 413/2014 stood out. Nonetheless, the Spanish renewable sector, and especially the solar power secto... [more]

This study assessed suitable smart grid areas for power generation and distribution from solar and small hydro energy resources in Western Uganda by employing the fuzzy analytic hierarchy process (AHP) based on geographic information system (GIS) data. This was performed based on the selected economic, environmental, and technical criteria by the authors guided by the experts’ judgements in the weighing process. The main criteria also included various sub-criteria. The sub-criteria of the economic criterion included distance from transmission lines, topography, and distance to roads. The environmental sub-criteria covered land use, sensitive areas, and protected areas. The technical sub-criteria were on distance from demand centers, available potential energy resources (solar and hydro), and climate (rainfall and sunshine). The weights of the main criteria and the sub-criteria were calculated by using the fuzzy AHP. These weights were then used in the GIS environment to determine both... [more]

The energy efficiency of a renewable energy system is inextricably linked to the energy storage technologies used in conjunction with it. The most extensively utilized energy storage technology for all purposes is electrochemical storage batteries, which have grown more popular over time because of their extended life, high working voltage, and low self-discharge rate. However, these batteries cannot withstand the very low temperatures encountered in cold regions, even with these very promising technical characteristics. The cold northern temperatures affect the batteries’ electromotive force and thus decrease their storage capacity. In addition, they affect the conductivity of the electrolyte and the kinetics of electrochemical reactions, thus influencing the capacity and speed of electrons in the electrolyte. In this article, which is intended as a literature review, we first describe the technical characteristics of charge−discharge rate of different electrochemical storage techniqu... [more]

Offshore wind (OSW) has the potential to cut greenhouse gas (GHG) emissions and halt damaging climate change. However, policies to foster an OSW industry in Norway have long been small and scarce. Recent events suggest that this is changing, as the state-owned enterprise Enova decided to grant a record NOK 2.3 bn to build the world’s largest floating offshore wind farm in 2019, the Hywind Tampen project. Based on previous work by the corresponding author, we summarize the political development of OSW in Norway to distil generalisable lessons. The corresponding author employed interviews, document analysis and process tracing, using a theory of policy change to characterise the observed political change. She found that the main obstacle for early OSW deployment has been that environmental and visibility concerns have exacerbated energy−political ones that are created by a longstanding lack of local energy demands. As the green energy demand on a global scale is soaring, the lack of OSW... [more]

Acceleration of energy transition will become the crucial social, political and technical challenge of the 21st century and will be largely associated with the growing use of renewable energy sources, including solar power. This study provides some experimental results of using solar hot water systems (HWS) embedded in apartment buildings located in the energy-efficient district called Zhatay in Yakutsk city, in the Republic of Sakha (Yakutia). The low annual solar fraction of HWS was found for 2019. It is equal to 0.2869 and caused by thermal energy loss from the hydraulic circuit during the nighttime. The study suggests increasing solar fraction in HWS and implementing a software and hardware system. The experimental evaluation of these studies was performed by testing a solar water heating pilot plant in Kaftanchikovo village in Tomsk Region (Western Siberia). As a result of HWS testing, it was found that the annual solar fraction can be significantly increased by preventing the hea... [more]

With heightening global concerns about the impacts of climate change, the debate around different carbon mitigation options is gaining momentum. A widespread argument is between those for and against utilizing nuclear energy as a low-carbon energy source. This debate is also relevant for Turkey, a country that is set to introduce nuclear energy to its electricity generation mix over the coming years. The purpose of the study is to assess the potential merits and drawbacks of the utilization of nuclear energy in the country versus the increased utilization of renewable energy sources. A fundamental merit order model is used for modeling the Turkish electricity market until 2025 under three scenarios. The comparative effects of renewable energy sources and nuclear energy are evaluated in terms of their impact on electricity generation costs, CO2 emissions and energy security. The results of the study show that the increased utilization of renewable energy has a more effective role in ach... [more]

Airborne wind energy (AWE) systems use tethered flying devices to harvest higher-altitude winds to produce electricity. For the success of the technology, it is crucial to understand how people perceive and respond to it. If concerns about the technology are not taken seriously, it could delay or prevent implementation, resulting in increased costs for project developers and a lower contribution to renewable energy targets. This literature review assessed the current state of knowledge on the social acceptance of AWE. A systematic literature search led to the identification of 40 relevant publications that were reviewed. The literature expected that the safety, visibility, acoustic emissions, ecological impacts, and the siting of AWE systems impact to which extent the technology will be accepted. The reviewed literature viewed the social acceptance of AWE optimistically but lacked scientific evidence to back up its claims. It seemed to overlook the fact that the impact of AWE’s charact... [more]

The article concerns the issue of the existence of non-obvious relationships and of potential correlations between the emission of greenhouse gases and particulate matter (PM), renewable energy and corruption perceptions. Additionally, it analyses the possible impact of these above-mentioned connections on the economic, environmental and social situation in the context of further economic development, including during the COVID-19 pandemic and in relation to European countries. The issue of reducing dirty energy sources and corrupt activities is not only a problem considered at the state level, but it is very closely related to the operation of many private enterprises. The conducted research applied methods of desk research as well as comparative quantitative analyses and used extensive statistical data of most European Union member states as well as the United Kingdom and Norway. The ambiguity of the results obtained in the research does not allow for an explicit verification of the... [more]

Greenhouse gas emissions need to be drastically reduced to mitigate the environmental impacts caused by climate change, and to lead to a transformation of the European energy system. A model landscape consisting of four final energy consumption sector models with high spatial (NUTS-3) and temporal (hourly) resolution and the multi-energy system model ISAaR is extended and applied to investigate the transformation pathway of the European energy sector in the deep emission mitigation scenario solidEU. The solidEU scenario describes not only the techno-economic but also the socio-political contexts, and it includes the EU27 + UK, Norway, and Switzerland. The scenario analysis shows that volatile renewable energy sources (vRES) dominate the energy system in 2050. In addition, the share of flexible sector coupling technologies increases to balance electricity generation from vRES. Seasonal differences are balanced by hydrogen storage with a seasonal storage profile. The deployment rates of... [more]

The aim of this work is to develop a model of heat supply to buildings with almost zero energy consumption, indicating the significant importance of heat losses and gains in heating installations. The prepared model is to indicate the need for changes in the structure and topology of heating installations, resulting from the changing heat demand of buildings. The need to create a new model is heightened by changes that relate to tightening legal regulations related to energy consumption and demand, which must meet the standards of buildings in Poland from 2021. The article presents the assumptions and results of analyses of the use of energy installations in residential buildings that use renewable energy sources to balance energy consumption in various areas of its use. To achieve this goal, calculations were made using simulations of the impact of the use of installations using renewable energy sources on the energy performance of a building with different quality of partitions and i... [more]

Hydrothermal liquefaction (HTL) uses heat and pressure to liquefy the organic matter in biomass/waste feedstocks to produce biocrude. When hydrotreated the biocrude is converted into transportation fuels including sustainable aviation fuel (SAF). Further, by liquifying the organic matter in wet wastes such as sewage sludge, manure, and food waste, HTL can prevent landfilling or other disposal methods such as anerobic digestion, or incineration. A significant roadblock to the development of a new route for SAF is the strict approval process, and the large volumes required (>400 L) for testing. Tier α and β testing can predict some of the properties required for ASTM testing with <400 mL samples. The current study is the first to investigate the potential for utilizing wet-waste HTL biocrude (WWHTLB) as an SAF feedstock. Herein, several WWHTLB samples were produced from food waste, sewage sludge, and fats, oils, and grease, and subsequently hydrotreated and distilled to produce SAF sa... [more]

The energy transition has shown that fossil generation can be complemented with renewable energy and other resources capable of providing flexibility to the energy system’s operation, in compliance with the wholesale electricity market’s rules. This paper proposes a market-based methodology for introducing flexible demand in the energy dispatch, optimizing the scheduling of electricity system operation in the short-term, and considers the challenge of implementing an incentive scheme for participants in demand-response programs. The scheme includes the criteria of the elasticity of substitution and a renewable energy quota. This methodology is focused on a strategic demand shift to minimize the cost of supply; increase the dispatch of renewable energy; control CO2 emissions; and satisfy the generation, demand, and transmission operating constraints. These conditions encourage the development of a simulation tool that allows a sensitivity analysis to aid decision-making by operators and... [more]

Renewable distributed generators (RDGs) are widely embedded in electrical distribution networks due to their economic, technological, and environmental benefits. However, the main problem with RDGs, photovoltaic generators, and wind turbines, in particular, is that their output powers are constantly changing due to variations in sun irradiation and wind speed, leading to power system uncertainty. Such uncertainties should be taken into account when selecting the optimal allocation of RDGs. The main innovation of this paper is a proposed efficient metaheuristic optimization technique for the sizing and placement of RDGs in radial distribution systems considering the uncertainties of the loading and RDG output power. A Monte Carlo simulation method, along with the backward reduction algorithm, is utilized to create a set of scenarios to model these uncertainties. To find the positions and ratings of the RDGs, the artificial gorilla troops optimizer (GTO), a new efficient strategy that mi... [more]

In this manuscript, a novel topology is proposed to integrate on-grid and off-grid PV systems supplying the same load premises. The load side is investigated and analyzed, and critical and non-critical loads are separated in terms of power supply. Critical and seasonal loads usually place stress on the grid’s point of common coupling (PCC). In the proposed topology, they are supplied by a novel topology for an off-grid solar pump PV system that lacks energy storage integration. The lack of energy storage batteries requires a novel design and sizing scheme for the off-grid PV system, and a methodology is proposed in this manuscript. The on-grid PV system is conventionally designed and coupled with the storage-less off-grid PV system to maintain load supply. The proposed methodology minimizes the ratings of the PCC and hence relieves stress on congested grids with renewable energy penetration, especially in condensed urban areas. The proposed structure enables the operation of microgrids... [more]

Distributed generation systems (DGSs) are one of the key developments enabling the energy transition. DGSs provide users with increased control over their energy use and generation, but entail greater complexity in their design and operation. Traditionally, optimization models have been used to overcome this complexity, and currently, research is focusing on integrating uncertainties on them. This review attempts to analyze, classify and discuss 170 articles dealing with optimization of DGSs under uncertainty. A survey has been performed to identify the selected manuscripts and the strengths and weaknesses of previous reviews. As a result, an innovative classification has been designed and the distinct elements of optimization models in DGSs have been highlighted: microgrid architecture, sources of uncertainty, uncertainty addressing methods, problem types and formulations, objective functions, optimization algorithms and additional features. Each part is detailed thoroughly to provide... [more]

The countries of the Gulf Cooperation Council (GCC)—Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates—hold almost 30% of the world’s total proven oil reserves and around 20% of its total proven natural gas reserves. They are also endowed with a high abundance of renewable energy resources such as solar and wind. Yet, the GCC’s primary energy consumption is still dominated by fossil fuels, and the share of renewable energy still does not exceed 1%. Drawing on secondary data, including journal articles, governmental and companies’ websites, and reports and newspaper articles, this paper assesses the reasons behind their underutilization of renewable energy resources. Whereas technical and economic feasibility issues had been identified as the main barriers to slow the uptake of renewable energy technologies in the GCC, this paper uncovered that various additional factors have remarkably influenced such delays. High hydrocarbon subsidies, low electricity tariff stru... [more]

The Polish economy is facing a huge challenge regarding the future of energy in Poland. The current energy system is very inefficient, it consumes huge resources that, like countries with high energy efficiency, could be allocated to the development of low-carbon and renewable energy networks. At the moment, the Polish energy sector, related to the coal monoculture, lacks electricity and the entire transmission system is obsolete. The solution may be distributed energy, which can ultimately satisfy energy supplies in less urbanized areas and in rural areas, while guaranteeing the sustainable development of these areas. In order to take up the challenge of better understanding and explaining such a complex reality, it was decided that the research framework of this article will be distributed energy in the region. The aim of the article is to ensure energy security in the conditions of innovative, ecological and open to competition regional energy using local energy resources. Currently... [more]

Exergy and energy analyses of two biodiesel production processes that integrate solar energy as the main energy source were developed to determine the process with the higher efficiency from an energy and exergy approach. The biodiesel production processes were simulated in ASPEN PLUS®, and the solar energy supply was studied in TRNSYS®, using EXCEL® simultaneously for the exergetic analysis. The solar thermal energy collection system can supply 81% of the energy required by the alkali process in the Flash separation equipment. For the supercritical process, solar thermal energy can supply 74.5% of the energy in the preheating and separation stages. The energy efficiency of the supercritical process is higher; nevertheless, the exergetic efficiency of the alkaline process is higher than the supercritical one. Solar collection systems contribute from 85% to 93% of the exergy destroyed by the global process for both cases. The alkaline biodiesel production process has the highest advanta... [more]

(1) The German energy system transformation towards an entirely renewable supply is expected to incorporate the extensive use of green hydrogen. This carbon-free fuel allows the decarbonization of end-use sectors such as industrial high-temperature processes or heavy-duty transport that remain challenging to be covered by green electricity only. However, it remains unclear whether the current legislative framework supports green hydrogen production or is an obstacle to its rollout. (2) This work analyzes the relevant laws and ordinances regarding their implications on potential hydrogen production plant operators. (3) Due to unbundling-related constraints, potential operators from the group of electricity transport system and distribution system operators face lacking permission to operate production plants. Moreover, ownership remains forbidden for them. The same applies to natural gas transport system operators. The case is less clear for natural gas distribution system operators, wh... [more]

Worldwide, the use of fossil fuels covers almost 80% of the entire energy needs. In the European Union (EU), 2020 represents a watershed: for the first time, renewables were the main source of electricity. In Italy, the latest surveys demonstrate an increase in the use of alternative energy sources. European legislative framework highlights the importance of these new trends encouraging (and imposing) the use of renewables. The necessity to become more proactive in the energy production−consumption process and in the achievement of sustainability targets brings people to create Energy Communities (ECs) to manage their own energy supply chain. The authors present an overview of the main legislative framework in the EU and Italy in relation to ECs, analyzing the energy consumption, the electricity and heat energy production potentiality, and the energy balance in a portion of an Italian middle-size city in the Milan metropolitan area. Moreover, they underline the technical, regulatory, a... [more]

It is imperative to use clean energy in order to achieve “carbon neutrality” and “carbon peaking”. This research aims to explore the impact of the agricultural mechanization level, the rural infrastructure construction level, and the rural economic development level on the utilization of high-quality straw energy, and, resultingly, this study aims to help provide suggestions for promoting high-quality straw energy utilization, develop the potential of high-quality straw energy, and alleviate China’s energy shortage problem. This paper develops a measurement model using the ridge regression model with panel fixed effects, which overcomes the multi-collinearity problem among the various factors influencing the utilization of high-quality energy from straw. Panel data from 24 provinces and cities, from 2009 to 2017, are used. The results show that the improvements of the agricultural mechanization level, the rural infrastructure construction level, and the rural economic development level... [more]

We provide an open, available, and ready-to-use data set covering 40 years of hourly wind speeds and synthetic hourly production signals for the 29 biggest offshore wind farms in Europe. It enables researchers and industry experts to include realistic offshore time series into their analyses. In particular, we provide data from 1980 to 2019 for wind farms already in operation and those that will be in operation by 2024. We document in detail how the data set was generated from publicly available sources and provide manually collected details on the wind farms, such as the turbine power curves. Correspondingly, the users can easily keep the data set up to date and add further wind farm locations as needed. We give a descriptive analysis of the data and its correlation structure and find a relatively high volatility and intermittency for single locations, with balancing effects across wind farms.

The Ukrainian renewable energy sector has demonstrated a significant increase in its renewable power capacity, especially for solar and wind power plants. Decommissioning the end-of-life equipment in Ukraine has not yet taken place, but it is only a matter of time. With this in mind, this paper assesses the quantities and the market values of the materials that could potentially be recovered from used solar and wind power plants, and it estimates the impact of their decommissioning on employment in Ukraine. It has been estimated that approximately 8.9 GW of solar power plants, and 3.6 GW of wind power plants, will be decommissioned from 2044 to 2059, and that the cost of the raw materials recovered could reach EUR 421.4 million and EUR 124.6 million in 2021 prices, respectively, compared to the decommissioning costs of EUR 240.1 million and EUR 49.1 million, respectively. Decommissioning renewable power plants will require the creation of new jobs, including 11.6 thousand in the solar... [more]