An underappreciated source of renewable energy is wastewater, both municipal and industrial, with global production exceeding 900 km3 a year. Wastewater is currently perceived as a waste that needs to be treated via energy-consuming processes. However, in the current environmental nexus, traditional wastewater treatment uses 1700−5100 TWh of energy on a global scale. The application of modern and innovative treatment techniques, such as microbial fuel cells (MFC), would allow the conversion of wastewater’s chemical energy into electricity without external energy input. It has been demonstrated that the chemically bound energy in globally produced wastewater exceeds 2.5 × 104 TWh, which is sufficient to meet Europe’s annual energy demand. The aim of this paper is to answer the following questions. How much energy is bound in municipal and industrial wastewaters? How much of that energy can be extracted? What benefits will result from alternative techniques of waste treatment? The main f... [more]

The efficient use of energy resources is profoundly changing power grid regulation and policy. New forms of power generation coupled with storage and the presence of new, increasingly flexible loads such as electric vehicles enable the development of multi-agent planning systems based on new forms of interaction. For instance, consumers can take advantage of flexibility by interacting directly with the grid or through aggregators that bridge the gap between these end-users and traditional centralised markets. This paper aims to provide insight into the benefits for aggregators and end-users from a financial perspective by proposing a methodology that can be applied to different scenarios. End-users may provide flexibility services related to private vehicle charging stations or battery storage systems. The paper will analyse different remuneration levels for end-users by highlighting the most beneficial scenarios for aggregators and end-users and providing evidence on potential conflic... [more]

Currently, the industrial sector consumes more than 60% of the energy produced in Mexico, mainly from fossil fuels, causing negative impacts on the environment and human beings. Solar energy helps companies diversify their energy sources, generate savings, and reduce dependence on fossil fuels. Moreover, the environmental impact can be reduced when CO2 emissions are reduced. Nevertheless, in Mexico, less than 3.5% of the electricity comes from solar energy, and along with a lack of information about the technical and social aspects involved in photovoltaic (PV) systems, it is difficult for companies to analyze and evaluate relevant data, and thus make effective decisions based on their needs. As such, companies cannot understand the complete lifecycle of PV systems, and, usually, the economic, environmental, and technical decisions are made only using the installation analysis, which is only one stage in the lifespan of PV systems. This paper proposes an S4 framework with the sensing,... [more]

This paper presents the impact of flow changes in the Warta River and water management rules regarding the Jeziorsko dam reservoir on the energy production by the hydropower plant in the period 1995−2021. The Jeziorsko dam reservoir was built in 1986. It is the second largest dam reservoir in Poland in terms of surface area. In 1994, a hydropower plant with an installed capacity of 4.89 MW started operation. The study results show the average annual energy production from 1995 to 2021 at a level of 18,718 MWh. On the other hand, energy production largely changed from year to year, from 12,432 MWh (in 2019) to 26,916 MWh (in 2001). The droughts that have occurred in the Warta River basin over the past two decades have had a major impact on energy production. As a consequence of the drought, it was not possible to maintain the required water level in the reservoir. Moreover, a change in the rules for the reservoir’s management that led to lower water levels in the reservoir by 1.5 m betw... [more]

A large reduction in greenhouse gas (GHG) emissions will be needed in the coming decades to keep global warming well below 2 °C. Together, energy and transport sectors are responsible for around ¾ of carbon dioxide (CO2) emissions worldwide. The transition to a low-carbon economy involves an increase in the share of renewable energies in power grid and the electrification of the transports thus demanding policies focused on the joint diffusion of the two technologies This study adopted a hybrid methodology to examine several types of policies and their implications in the use and diffusion of the electric vehicles charged with renewables. We argue that it is not enough to have policies to expand electric mobility with renewable sources. The results reveal that production and technology represent ⅓ of electric vehicles and renewables policies. Broad coverage of policies does not translate into market gains since 20% of the countries that encourage electric vehicles have a low market sha... [more]

Are small-scale wind turbines green? In this study, we perform a ‘cradle to grave’ life cycle assessment of a novel domestic-scale 10 kW vertical axis wind turbine tree which uses combined Savonius and H-Darrieus blades. Situated at a test site in Surat Thani, Thailand, SimaPro software was used to evaluate the environmental impact profile of the tree. Comparisons to the Thai grid mix were made, using both with and without end-of-life treatments. Impact profiles were calculated using wind data collected over two years at Surat Thani, and from wind data from a higher capacity factor (CF) site at Chiang Mai, Thailand. Energy and greenhouse gas payback times were estimated for both locations. The relative magnitudes of impacts were compared with environmental prices protocol, and we investigated reductions in impacts using three mitigative scenarios: changes to design, transportation and materials. The results showed that Chiang Mai had a CF = 7.58% and Surat Thani had a CF = 1.68%. A tot... [more]

Keeping the global temperature rise below 2 degrees Celsius, as foreseen by the Paris Agreement, requires a new global roadmap for the energy transition. For this reason, the European Commission decided to directly involve local municipalities in reaching these objectives through multilevel, bottom-up actions for sustainable energy. The Covenant of Mayors is a very concrete demonstration of this trend of development and adoption of sustainable energy action plans (SEAP), rethinking the way cities operate and bringing them closer to energy self-sufficiency, with measures favouring local economic development and improving citizens’ quality of life. The numerous RES/RUE actions included in SEAPs at the regional level have led both to the request for huge funding and to increased complexity for regional managers to identify the best projects to be financed. To manage the multitude of data (emissions, energy consumption, cost, etc.) present in the SEAPs at a regional level, a web-based plat... [more]

The Kingdom of Saudi Arabia (KSA) has an ambitious plan to install 40 GW of solar photovoltaic (PV) capacity via large scale projects (majority of which are >100 MW) across the country by 2030. These projects are required to achieve a threshold percentage of the overall project cost as in country expenditure, termed “local content”. This threshold will rise to 40−45% by 2028, ensuring solar projects do not simply become investment opportunities for overseas companies but deliver jobs and skills development within the Kingdom. Local content is assessed across all aspects of a PV system—module, inverter, structure, etc. Typically, the PV module cost can range between ~34% to ~44% of the overall system cost. However, 56% of this module cost represents the manufacture of the solar cells. To maximise local content, the opportunity for KSA lies in module fabrication of imported solar cells. This study assesses the capacity readiness of the KSA to meet this opportunity in relation to its 2030... [more]

Fertilization is an essential element in plant cultivation. Supplying the right amounts of nutrients allows plants to grow and develop. Due to the rising price of mineral fertilizers, other fertilizers and soil conditioners are growing in importance. One of these is the digestate produced in agricultural biogas plants. Due to its properties, the digestate can be used directly as a fertilizer. In this case, the effects of application can both change the soil environment and directly affect plant growth. Physical, biological, and thermal transformations can also produce products based on the digestate or its fractions, which can be successfully used for fertilizer purposes. Among other things, this paper discusses the production and use of composts, biocarbon, and/or fertilizer granules from the solid fraction of the digestate. Numerous scientific studies, including the authors’ own research in this article, indicate that digestate can be successfully used as fertilizer, both without pro... [more]

Renewable energy sources (RES) are currently the main alternative to fossil fuels and are also seen as an important contributor to slowing down the dangerous climate change on our planet. Energy supplied from renewable sources can reduce the consumption of primary raw materials and reduce emissions of harmful substances that enter the atmosphere in the process of producing electricity and heat, having a negative impact on the environment. This paper provides a multivariate comparative analysis of EU countries in terms of the use of renewable energy. The empirical research used seven variables defining the complex phenomenon under study, collected for 27 EU countries between 2011 and 2020. The research method used was the dynamic version of the non-model method, with a normalisation method based on zero unitarisation. The results of the study confirm that there was a positive change in the use of renewable energy in most EU countries between 2011 and 2020. High levels of renewable energ... [more]

This study examined an Organic Rankine Cycle powered by a parabolic trough collector and a two-tank thermal storage system based on the development of a mathematical model, for the conditions of the city of Itajubá in Brazil. First, geometrical optics and heat transfer models of the collector−receiver set were used to determine the thermal equilibrium of the solar thermal collector system and parameters such as the efficiency of the solar field, heat and optical losses, and thermal energy of the outlet fluid. Next, the thermal equilibrium of the Organic Rankine Cycle was found in order to establish its operational parameters. Finally, the behavior of the thermal storage system was analyzed through its modeling. Once the characterization of the storage system was completed, the integrated operation of the proposed system was evaluated. Given Itajubá’s weather conditions, the results indicate that an electricity generation system can be implemented with the Solel UVAC Cermet selective co... [more]

Since the global warming problem threatens the whole world, it is understood that countries should develop energy policies that will increase their sustainable and clean energy investments. Compared to other alternatives, the high cost of renewable energy projects is an essential obstacle in this process. Therefore, priority should be given to developing distributed energy projects to minimize this problem. The scope of the present paper is to identify the most critical items that affect the performance of distributed energy projects to have knowledge-oriented competencies. In this way, companies can focus on more critical items to provide efficiency for distributed energy projects. As a result, clean energy usage is improved, and the global warming problem is handled more successfully. A novel decision-making model is generated to examine the competencies of the knowledge economy based on collaborative filtering and bipolar q-rung orthopair fuzzy sets (q-ROFSs) with the golden ratio.... [more]

In respect to CO2 emissions, the post-Soviet states are a scientifically interesting object of research, as each of the countries has developed via different paths since reclaiming independence from the Soviet Union. Given that each country has a different approach to the use of fossil resources, it is essential to assess their input to global carbon footprint individually. Such assessment then allows to find certain actions in the development of legislation and to apply focused techniques to reduce carbon emissions. The aim of this study was to evaluate the fossil CO2 emissions produced in the Baltic States from 1991 onward, describing challenges relating to sustainability and socio-economic, scientific, and integrated approaches to sustainable development, including clean and efficient use of energy, and thus addressing climate challenges. This paper reports on data on CO2 emissions in the Baltic States. The results show that the transition of the Baltic States from the specificities... [more]

This publication presents the impact of PM10, PM2.5, and cloudiness on the power that is generated by photovoltaic panels—the actual photovoltaic power was measured. Weather parameters that were recorded by a weather station were taken into account, and the dependencies between the weather parameters and the power that was generated by PV panels were determined. This study was based on actual data from a solar cell set and was designed to allow a certain size of a PV system to be able to supply power to a given load. For the entire measurement year, data on PM10, PM2.5, cloudiness, and generated power were collected; by using a genetic algorithm, the influence of the environmental parameters on the power that was generated by the PV panels was calculated. The research shows the influence of anthropogenic factors on the power that is generated by PV panels. It was observed that PM2.5 and PM10 air pollution decreased the power by about 16% among the analyzed factors as they were related... [more]

Successful energy transitions, also referred to as leapfrog development, present enormous prospects for EU nations to become carbon neutral by shifting from fossil fuels to renewable energy sources. Along with climate change, EU countries must address energy security and dependency issues, exacerbated by factors such as the COVID-19 pandemic, rising energy costs, conflicts between Russia and Ukraine, and political instability. Diversifying energy sources, generating renewable energy, increasing energy efficiency, preventing energy waste, and educating the public about environmental issues are proposed as several strategies. The study draws the conclusion that central European countries may transition to a clean energy economy and become carbon neutral on economic and strategic levels by locating alternative clean energy supply sources, reducing energy use, and producing renewable energy. According to the study, the EU energy industry can be decarbonised and attain energy security using... [more]

This article studies the broad methodology and major application of smart distributed energy resources (DER) in terms of energy generation, consumption, transaction, and power scheduling. This article simplifies a general DER system into a generic type of integrated DER model. This model is used to investigate a smart DER system that transforms three input parameters, (3I parameters) into three critical output functions(3O functions); hence, the model is also called the 3I3O model. The power at a common connection joint can be enabled by a computer that makes computerized decisions to utilize smart DER. Therefore, the computer algorithm collects various data fed into a computer for deep learning and artificial intelligence (AI) decision making. The authors demonstrate important results and the best solutions to meet power demand, offer an economic advantage and have a low carbon footprint for consumers. Moreover, several network blockchain options are discussed. EBC and DER represent a... [more]

Renewable energy provides an effective solution to the problem existing between energy and environmental protection. Tidal energy has great potential as a form of renewable energy. Tidal current generation (TCG) technology is the earliest renewable energy power generation technology. The advancement of science and technology has led to TCG rapidly developing since its emergence in the last century. This paper investigates the development of TCG in recent years based on the key components of TCG systems, both in terms of tidal energy harvesting research and power generation unit research. A summary of tidal energy harvesting is presented, investigating the main tidal energy harvesting units currently available. In addition, research on generators and generator control is summarized. Lastly, a comparison between horizontal and vertical axis turbines is carried out, and predictions are made about the future trends in TCG development. The purpose of this review is to summarize the research... [more]

The Paris Climate Agreement and the 2030 Agenda for Sustainable Development Goals declared by the United Nations set high expectations for the countries of the world to reduce their greenhouse gas (GHG) emissions and to be sustainable. In order to judge the effectiveness of strategies, the evolution of carbon dioxide, methane, and nitrous oxide emissions in countries around the world has been explored based on statistical analysis of time-series data between 1990 and 2018. The empirical distributions of the variables were determined by the Kaplan−Meier method, and improvement-related utility functions have been defined based on the European Green Deal target for 2030 that aims to decrease at least 55% of GHG emissions compared to the 1990 levels. This study aims to analyze the energy transition trends at the country and sectoral levels and underline them with literature-based evidence. The transition trajectories of the countries are studied based on the percentile-based time-series an... [more]

This paper proposes a buffered microgrid with a modular grid interface consisting of a modular back-to-back converter. The proposed method provides a flexible strategy that enables both the load and generation expansion of the microgrid, with no sizing constraints on the initial stage. The method maintains the physical separation of the buffered microgrid from the grid by using back-to-back converters, which ensures a safe, secure and seamless operation in both islanded and grid-connected operation modes. The proposed modular structure allows an energy exchange prioritization either between the energy storage systems and the grid or between the energy storage units themselves, depending on the recommended/desired operational strategy. The prioritizations are achieved by using sets of dead zones in the control of the interfacing converters. In order to control the voltage and frequency, an inverse-droop-based dq-frame current control method was implemented in PSCAD/EMTDC to substantiate... [more]

This study comprehensively examines the effects of the COVID-19 pandemic on energy consumption in the United States. The purpose of the study is to quantify the effects of lockdowns and pandemic disruptions on energy consumption trends in order to inform policymakers and utilities on how to prepare for such events in the future. The study focuses on 2020 data collected by the Federal government. The effects are quantified using descriptive statistics. State-wise and sector-wise data have been presented using plots and heat maps. Related metrics like COVID case data, GDP, emissions, and expenditures were also presented. The total energy consumption fell by 7.5% in 2020. Besides Alaska, every state saw a decrease in energy, with some as high as 26%. The residential sector had the most states that saw an increase in energy, stemming from lockdowns and working from home. Similarly, petroleum consumption saw a decrease of 11.4% as a result of a decrease in travel. Biomass-related renewable... [more]

Southern Africa has a huge potential for renewable energy sources such as hydro, solar, wind, biomass, and geothermal. However, electricity access remains a key policy issue for most member states, with a global average access to electricity of only 54% in 2019. This low electrification rate is a strong motivation for member states to increase renewable energy use and improve access to electricity for all. The goal of this paper was to present a literature review of methodologies, energy plans, and government programs that have been implemented by the Southern African Development Community member states to address the region’s low average electrification rate and greenhouse gas emission reduction targets. The study presents the most commonly used methodologies for the integration of renewable energies into electrical systems, considering the main grid and distributed generation systems. LCOE minimization methodologies and software options, such as GIS, HOMER, LEAP, and EnergyPLAN, are... [more]

Southern Africa has a huge potential for renewable energy sources such as hydro, solar, wind, biomass, and geothermal. However, electricity access remains a key policy issue for most member states, with a global average access to electricity of only 54% in 2019. This low electrification rate is a strong motivation for member states to increase renewable energy use and improve access to electricity for all. The goal of this paper was to present a literature review of methodologies, energy plans, and government programs that have been implemented by the Southern African Development Community member states to address the region’s low average electrification rate and greenhouse gas emission reduction targets. The study presents the most commonly used methodologies for the integration of renewable energies into electrical systems, considering the main grid and distributed generation systems. LCOE minimization methodologies and software options, such as GIS, HOMER, LEAP, and EnergyPLAN, are... [more]

Most of the world’s energy requirements are still derived from natural resources. This will result in a catastrophic energy crisis with negative environmental consequences. The increased energy supply will result in greater consumption of non-renewable sources. The production of biomass producer gas (BPG) from biomass gasification has received significant attention as an alternative fuel due to the depletion of non-renewable resources. This experimental study aimed to determine the flame propagation, flame propagation speed, and chamber pressure trace of BPG at different equivalence ratios. Understanding the characteristics of the BPG’s combustion, finding lower greenhouse gas emissions of BPG, and minimizing the use of fossil fuels is necessary to mitigate these problems. Using the direct visualization technique, an optical constant volume combustion chamber (CVCC) was developed to measure combustion characteristics. Liquid petroleum gas (LPG) was used to compare the flame propagation... [more]

In recent years, Taiwan has firmly committed itself to pursue the green energy transition and a nuclear-free homeland by 2025, with an increase in renewable energy from 5% in 2016 to 20% in 2025. Offshore wind power (OWP) has become a sustainable and scalable renewable energy source in Taiwan. Maritime Spatial Planning (MSP) is a fundamental tool to organize the use of the ocean space by different and often conflicting multi-users within ecologically sustainable boundaries in the marine environment. MSP is capable of definitively driving the use of offshore renewable energy. Lessons from Germany and the UK revealed that MSP was crucial to the development of OWP. This paper aims to evaluate how MSP is able to accommodate the exploitation of OWP in Taiwan and contribute to the achievement of marine policy by proposing a set of recommendations. It concludes that MSP is emerging as a solution to be considered by government institutions to optimize the multiple use of the ocean space, reduc... [more]

The transition towards net-zero emissions is inevitable for humanity’s future. Of all the sectors, electrical energy systems emit the most emissions. This urgently requires the witnessed accelerating technological landscape to transition towards an emission-free smart grid. It involves massive integration of intermittent wind and solar-powered resources into future power grids. Additionally, new paradigms such as large-scale integration of distributed resources into the grid, proliferation of Internet of Things (IoT) technologies, and electrification of different sectors are envisioned as essential enablers for a net-zero future. However, these changes will lead to unprecedented size, complexity and data of the planning and operation problems of future grids. It is thus important to discuss and consider High Performance Computing (HPC), parallel computing, and cloud computing prospects in any future electrical energy studies. This article recounts the dawn of parallel computation in po... [more]