Renewable Energy Sources Technologies Research Articles

Load Frequency Control With Renewable Energy Sources Using Practical Swarm Optimization Based On PID

Future competitive solutions for the production of electricity may be provided by emerging renewable energy sources (RESs) technologies as wind, solar photovoltaic, and solar thermal power systems. In this study, simulation tests have been conducted on autonomous hybrid generating systems(HGSs) made up of diesel engine generators (Degs), fuel cells (FCs), wind turbine generators (Wpg), solar photovoltaic generators (Pvpg), battery energy storage systems (Bess), and flywheels (Fess). The abrupt fluctuations in load, generation, or both cause the power system's frequency to vary. PID controller tuning using particle swarm optimization (PSO) is used for the optimization of controllers’ gains of the proposed hybrid systems. The proposed method is compared with a genetic algorithm (GA) and a traditional PID controller. To test the proposed controller, three different scenarios were used: first, changing the load's value with a fixed value over a set period of time; second, changing the load's value with variable values; and third, changing the load's value with a variable value while changing the system parameters. The simulation results reveal that the suggested controller performs better and is more resilient against load and generational disruptions by reducing the maximum overshoot value and settling time by 70% and 65%, respectively, and by 14.2% and 5% when compared to a GA-PID control.

Architectural analysis of photovoltaic (PV) module applications on non-flat roofs

Due to the growing importance of renewable energy sources (RES) technology, a noticeable increase in interest in photovoltaics can be observed. Roofs most often provide the places where photovoltaic (PV) modules are installed. In many cases, ill-considered decisions concerning the selection of PV modules and their installation lead to unfavourable architectural effects. The article aims to examine the possibility of integrating PV modules installed on non-flat roofs with the broadly understood building architecture. An observational method based on case studies was applied to the study. Not only aesthetic aspects but also functional and technical aspects were considered while paying attention to energy issues. The conducted analysis indicates a good level of possibilities for integrating PV modules with architecture and these possibilities vary depending on the geometric features of the roof. Applications within full and glazed roofs are also rather distinctive.

Optimization & techno-economic analysis of a hybrid system with thermal energy storage within a LEC

The built environment is one of the most energy-intensive actors of energy. The formation of communities, which exploit energy locally, significantly affects the energy transition process to more viable scenarios. These communities, called Local Energy Communities (LECs), mainly use their primary energy resources to cover their heating and cooling needs. Such a community is the LEC of DUTh’s University campus in Xanthi, Greece. The community has installed several Renewable Energy Sources (RES) technologies to exploit the available primary energy and to cover the respective demands. However, an inability to cover the demand is observed in periods like winter or in periods of low renewable energy availability. To tackle that phenomenon, the authors investigated several optimization scenarios, which aim to mitigate the cost of investment as well as the cost of energy (levelized cost of energy - LCoE) and to maximize the thermal energy produced simultaneously — to cover the thermal energy demand — and the RES penetration in the energy mix. A multi-integer linear optimization (MILP) strategy was developed to achieve that. The results were further analyzed via a Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) analysis. The results of the study concluded that an ideal solution for the system might be an increase in solar collector area (by 40%), the thermal energy storage system’s (TESS) volume (by 213%), and the biomass boiler’s capacity (by 107%) to meet the load of 1,814.48 MWhth/yr and to provide the required energy security to the community. The selected scenario provided an LCoE of 0.16 €/kWh, which is slightly improved compared to the baselines (0.18 €/kWh).

Analysis of the use of geothermal heat pumps for heating and cooling of individual residential buildings

Today, humanity is beginning to realize the problem of the growing shortage of natural energy sources. The prices of these sources are rising uncontrollably and will continue to rise in the future. As the Republic of Moldova does not have its own fossil fuels fields and is totally dependent on foreign imports, the implementation of renewable energy sources technologies becomes vital. In this sense, the usage of closed type geothermal heat pumps with direct heat exchange in new and reconstructed residential buildings to replace traditional heating boilers is beneficial. They can be especially effective in areas where there are no gas supply pipelines. The purpose of the paper is to determine the perspectives of geothermal heat pumps using in residential buildings in the Republic of Moldova climatic conditions. Examples with implemented geothermal heat pumps and project solutions for heating/cooling and hot water supply systems for three individual residential buildings in the southern region of the Republic of Moldova were analyzed for task implementation. During the 2020-2021 heating season, it was not necessary to use the additional reserve heat source for the examined objects.

Definition of Scenarios for Modern Power Systems with a High Renewable Energy Share.

Recent environmental policies have led academic, industrial, and governmental stakeholders to plan scenarios with a high share of renewable energy sources (RES), to ensure that future energy systems, composed mostly of RES, can remain stable, match the demand during seasonal variations and are economically feasible. This article considers different energy scenarios to obtain various options in terms of size, generation technologies, and grid configuration. The scenarios are studied in the POSYTYF project and are quantified through an optimization-based algorithm, where the test grids topologies are based on specific locations in Europe, and real data related to the availability of RES, as well as the demand. Different RES technologies are considered to meet requirements of grid integration of renewables at different horizons of time, up to 100% in the most futuristic case. The optimization algorithm is applied to three scenarios. It is shown that solar photovoltaic (PV) and wind can provide the renewable backbone, but they lack flexibility to achieve a very high share in the energy mix. Solar thermal and pumped hydro become important to cover the last range of integration, as they provide high flexibility, which is crucial for high share, but they are expensive for low share.

FEATURES OF THE GLOBAL FUEL AND ENERGY SECTOR DEVELOPMENT UNDER GLOBAL STRUCTURAL TRANSFORMATION

The article studies the features of the global fuel and energy sector’s development under structural transformational changes from 1971 to the present day. In the materials, the author analyzes the fuel structure of global generated electricity, compares the structure of global natural gas consumption, calculates and evaluates the dynamics of global consumption of various energy sources per capita, and analyzes the dynamics of global indicators of energy content of various energy sources to gross domestic product at purchasing power parity. Furthermore, an empirical analysis of indicators of the structure of change in renewable energy sources’ share of global gross production of electric power energy is conducted, as is the analysis of the structure of investments into the development of the renewable electric power industry in some countries, as well as global CO2 emissions since 1990. Firstly, the study reveals environmentally friendly and cost-effective energy sources such as natural gas and renewable energy sources technology, which strengthen their position in the global energy balance in the fuel structure of electric power generation while displace non-environmental petroleum and coal. Secondly, it has been proven that the indicators of the global energy efficiency level, calculated based on the energy content of all major energy sources consumed globally over the last century, are constantly dropping. The article describes the structure of a significant growth in renewable energy sources share of global gross production of electrical power. This trend is possible due to the accessibility of the technology for the production of renewable energy sources, the rise in the cost of crude hydrocarbons on global markets, “green” energy support at the state policy level in most countries, and massive investment in renewable energy sources. As a result of the study, it was concluded that the policy of managing the development of the global fuel and energy sector has a significant impact both on its future and on the development of the global economies of the world’s countries, primarily the Russian Federation.

The social perspective on small islands’ energy transitions

This paper reflects upon the concept of social innovation and its role in islands’ energy transition. As isolated energy systems, islands typically depend on energy imports from the mainland and mostly use fossil fuels for electricity, heating, and transport, which are significant sources of carbon emissions. At the same time, islands have an abundance of locally available renewable energy sources (RES) at their disposal, which makes them ideal test-beds for energy transition, or the technology-based switch of the energy system, from fossil-based to renewable energy. However, new RES technologies must be incorporated into society and, thus, to enable successful decarbonisation, technological innovations must be coupled with social innovations. Different authors stress that energy transitions are not strictly technical but socio-technical since they are also comprised of policies, politics and other artefacts, not just technological. Nevertheless, the role of social innovation in local energy transitions is still under-studied, and this paper aimed to contribute to this lack of literature, focusing on the local energy transitions of islands. By combining theoretical and empirical research, this paper aims to explore the role of social innovation in energy transition and analyse whether social innovation can be considered a success factor in the energy transition process of the case-study island, the small Croatian island of Unije.

The Application of a Multi-Criteria Decision-Making for Indication of Directions of the Development of Renewable Energy Sources in the Context of Energy Policy

This paper presents the application of multi-criteria decision-making (MCDM) for evaluating what technologies using renewable energy sources (RES) for electricity production have the chance to develop in Poland under the current socio-economic conditions. First, the Analytical Hierarchy Process (AHP) method was used to determine the weights of the optimization criteria. Five main criteria and 30 sub-criteria were identified. Next, the authors modified numerical taxonomy (NT) to rank eight RES technologies (such as onshore and offshore wind farms, photovoltaics, or biogas plants). The results show that offshore wind farms are the RES technology with the greatest development opportunities in Poland. The following three technologies: distributed photovoltaic energy, biogas plants, and biomass power plants, respectively, received a similar rating in the ranking. Hydropower and geothermal were the lowest-ranked technologies. The ranking, which is the result of multi-criteria analysis, in several respects, is significantly different from the directions of activities indicated in the state energy policy.

Impact of renewable energy sources technologies on power system stability: a Moroccan case study

<p>Most countries of the world have adopted renewable energy sources (RES) because of consistent policy and industry support. The use of these sources is expanding and will cover a larger part of the generation capacity in the future. Thus, power systems (PS) are experiencing the high scale RES integration. For a power system dominated by RES, the electrical grid characteristics, namely, the inertia constant (Hs) and the rate of change of frequency (ROCOF), should be evaluated. Furthermore, the requirements related to these characteristics should be specified in the grid code (GC) to reflect the actual needs of the transmission system operator (TSO) and to prepare the evolution of the RES penetration level. Due to the delay in specifying or updating these GC requirements, RES that are incorporating unsuitable functionalities for the future perspective, regarding fault-ride-through (FRT) and frequency support requirements, will remain operational by 2030; this will create additional constraints on the PS frequency stability after large-scale RES integration. In this paper, the impact assessment of deployed RES technologies on the Moroccan PS frequency stability is assessed by the year 2030, using MATLAB/Simulink environment. The main reason for focusing on the case study of Morocco is the country’s target of installing 52% of the energy supply from RES in the horizon of 2030.</p>

A Review of the Life Cycle Analysis Results for Different Energy Conversion Technologies

Technologies that use renewable energy sources (RES) are crucial to achieving decarbonization goals, but a significant number of studies show their relatively high environmental impact during the production phase. Therefore, technologies need to be compared in terms of their life-cycle environmental impact. The life cycle analysis (LCA) methodology is well known and widely employed. However, problems related to the methodological choices prevent taking full advantage of the LCA, as the results of numerous studies are often incomparable. The presented review aims to critically compare the impact of different energy generation technologies—RES (as well as non-RES) energy generators and co-generators. The numeric results are structured and analyzed in terms of the global warming potential (GWP) and non-RES primary energy consumption. The results show that RES technologies are superior compared to conventional fossil-fuel-based systems in most cases, and the high impact during the production and installation phases is compensated in the operational phase. The high variations in GWP from similar technologies result from different methodological choices, but they also show that the wrong choice of the technology in a certain location might cause serious environmental drawbacks when the impact of the RES technology exceeds the impact of fossil fuel-based technologies. Cogeneration technologies using waste as a fuel may even have a negative GWP impact, thus showing even higher potential for decarbonization than RES technologies.

Repurposing of a Closed Surface Coal Mine with Respect to Pit Lake Development

In the coal phase-out era, achieving sustainable mine closure is significant and prioritizes targets for the mining industry. In this study, the already closed lignite mine of Kardia, North Greece, is investigated, where the mine void left is naturally filled with water. The viability of different repurposing land uses is evaluated, and the natural water level development inside the mine pit is investigated concerning its future uses. The potential for solar photovoltaic (PV) panels developed on mining land and its surrounding area is evaluated in combination with the application of pumped hydro storage (PHS) technology, utilizing pit lake water. Except for electricity system planning, other end-uses that offer multiple, mutually reinforcing and lasting benefits are investigated, such as recreation parks, terrestrial wildlife, aquaculture and agriculture. All repurposing scenarios are evaluated with regard to the spatiotemporal evolution of the lake, by generating forecasts of the dependent variables (rainfall and temperature) via linear (autoregressive integrated moving average) and non-linear (artificial neural network) models. The prediction of pit lake natural development redefines the new land use layout and the land repurposing decisions. This is essential for strategic planning, considering the Greek lignite mining industry’s priority regarding transitioning from the current coal-based electricity to renewable energy sources (RES) technology.

Incorporating barriers in scenarios for energy efficiency improvement and promoting renewable energy in the Bulgarian residential sector

The progress in achieving targets for energy efficiency (EE) and renewable energy sources (RES) is hindered by a set of barriers linked with the end-users (social, educational, cultural, economic, and institutional), but previously, the effect of these barriers was only rarely quantified and no comprehensive methodology to do so is available. This paper, through a step-by-step methodology, examines the development of scenarios for the Bulgarian residential sector until 2030, focusing on the combination of available – for this sector – EE and RES technologies, after incorporating these barriers with the use of the HERON Decision Support Tool (HERON-DST). Two more research tools are used, LEAP (modeling tool) and AMS (multi-criteria evaluation method). Six different scenarios, three of which address barriers, were developed for LEAP. All scenarios are evaluated with the AMS method against a set of criteria/sub-criteria regarding their overall performance under the particular national framework. This results in the identification of the most appropriate (EE/RES) scenario for the country, i.e., addresses behavioral barriers and performs better (one with the highest AMS score) than the others under the particular national framework. This scenario promotes building shell improvement, efficient heating, and cooling in the Bulgarian residential sector. Its policy mixture mainly through financial incentives and more demanding building codes handles social, institutional, and economic barriers linked with end-users behavior. Conclusions concern the methodology, its outcomes, and future use.

Investigating the Environmental and the Energy Saving Behavior among School Principals through Classification Algorithms

Buildings are a significant energy consumption point since they account for 40% of the total energy demand and around 1/3 of greenhouse gas emissions. Energy-saving measures applied in the residential sector have led to a reduction in energy consumption during the last decade. On the contrary, such measures have not been widely applied in school buildings, although education is the second-largest energy consumer in the service sector. This paper aims to assess school principals' perceptions concerning energy saving and the environment since they are responsible for promoting energy-saving measures and investments and inspiring students and school personnel towards environmentally friendly behavior. Using survey data from Greek schools, we applied predictive classification models to locate the most critical variables that drive principals' perceptions of energy upgrading and energy-saving actions at school. Results revealed that the positive environmental perceptions of principals, the level of knowledge on Renewable Energy Sources (RES) and the active energy-saving behavior are related to energy-saving actions and energy upgrading in school environment. Furthermore, the creation of more RES oriented courses is related to positive energy-saving behavior and actions. Thus, emphasis should be put on educating and informing the school principals concerning RES technologies and energy-saving options since they are critical players in applying energy-saving measures in school buildings

Development of Grid Tied Inverter for Indian Grid and Operating Environmental Condition

Solar Photovoltaic (PV) technology is one of the renewable energy source technologies to realize the shift to decarbonize energy supply because of availability of safe, limitless, free and reliable long-term sources of power. PV modules/cells are instruments to convert this solar energy to DC energy. Grid interconnection with solar power system is comparatively easier to install as the same do not require storage system. This paper presents injection of 3 kW power generated from solar PV array to 230V grid distribution network. Technique uses phase angle difference between grid voltage and voltage source inverter. The grid acts like a virtual energy storage system with an unlimited storage capacity. Hence, the proposed system is designed without a battery backup. This system is simulated in MATLAB/Simulink to confirm the desire output. In the second step, hardware circuit is designed and implemented based on the simulation results.

РАЗРАБОТКА МИКРОГИДРОЭЛЕКТРОСТАНЦИЙ ДЛЯ МАЛЫХ РЕК ГОРНОЗАВОДСКОЙ ЗОНЫ ЧЕЛЯБИНСКОЙ ОБЛАСТИ

Small hydroelectric power generation is attractive from both an environmental and economic point of view. Technological innovations and mitigation measures are making small hydroelectric power plants an inexpensive and viable source of renewable energy which can be generated independently. They contribute not only to environmental protection, but also reduce human dependence on fossil fuels. This study is dedicated to finding solutions based on renewable energy source technologies and innovations using the example of the Chelyabinsk region. The experimental model of a micro-hydroelectric power station water wheel presented in this article, and the studies carried out on the basis of this model were used to carry out preliminary calculations. As a result, we found that such micro-hydroelectric power plants are capable of generating about 9–13 kW∙h, about 170–266 kW∙h/day and from 63 to 99 MW∙h/year.

Public Attitudes toward Renewable Energy in Croatia

Renewable energy sources (RES) play a key role in achieving the European Union’s energy and climate objectives. As a member of the European Union, Croatia has committed to adopting European Directive 2009/28/EC, a directive on promoting the use of RES. Croatia shows good potential for the use of different types of RES. In the period 2009–2019, the share of renewable energy in energy consumption increased from 23.6 to 28.5 percent. The Croatian energy strategy aims to increase the national share of renewable energy to at least 32 percent by 2030. Acceptance and public support are essential for renewable energy to be introduced into energy policy and particularly to encourage renewable energy implementation in the residential sector. The purpose of the paper is to explore the public perception of renewable energy and citizens’ willingness to pay for the use of RES. Data were collected through a 2021 survey of citizens 18 years and older. The survey results show a low level of implementation of RES technology in the residential sector; more than 80 percent of respondents did not use any sources of renewable energy in their households. Results related to respondents’ knowledge of different sources of renewable energy suggest they have the most knowledge of solar, wind, and hydropower energy. Respondents believe that combating climate change, reducing dependency on energy imports, reducing environmental impacts, and improving health are the most important benefits of RES implementation. The survey reveals general support for RES among respondents; almost 89 percent of them would purchase renewable energy from local suppliers. In addition, 79 percent of survey participants were willing to pay for the introduction of RES technology into their households. The research shows that environmental concerns are the primary reason for citizens’ higher willingness to pay for RES.

Renewable Energy Opportunities and Challenges in the U.S. Electricity Markets

During the last twenty years, the integration of Renewable Energy Resources (RESs) projects has become feasible in many electricity markets around the globe. The primary objective of these developments is to reduce carbon dioxide (CO2) emissions. In many countries, RESs integration projects could make a profit according to the subsidies policies of each electricity market. The United States (U.S.) electricity market is considered the most competitive one in the world. Hence, RES integration is subject to many financial and technical factors that eventually affect the integration process. Since the electricity production from RESs in the U.S. electricity market has become cost-effective, many projects have been implemented in a short period. In this paper, a discussion on the opportunities and challenges of renewable energy integration in the U.S. electricity market is demonstrated. The research starts with an overview of the electricity market in the U.S. with policies and bylaws governing the RESs integration. Some factors might empower the renewable energy deployment. Environmental aspects, government subsidies, regulations, and marginal cost price increase the renewable energy opportunities in the U.S. electricity market. By contrast, the paper discussed many challenges faced by renewable energy such as generation variability, intermittency, environmental issues, and capital and reserve cost. Such challenges might affect the electricity market prices. This paper provides an insight to the developed plans to implement RESs and control GHG emissions. In addition, corresponding policies to encourage RES integration and their technical impacts are highlighted. Restructuring the market and developing Renewable Energy Sources technologies are recommended to increase renewable energy market share in the future.

A Model-Based Approach to Decarbonize an Island’s Energy System

To achieve climate goals and contain further global warming, it is inevitable to reduce CO2 emissions especially in energy consumption. A way to do so is by integrating renewable energy sources (RES) into an energy system’s power generation. However, there is no standard procedure to decarbonise a locally restricted system. Therefore, the various local conditions have to be analysed and taken into consideration.
 The authors propose a model-based approach to decarbonise the energy system of the island Föhr, Germany. This includes various collected data sets on local conditions such as climate data and heat and power demand. The data is used to represent the island’s energy system and design a model-based solution in a simulation software.
 The authors identify potentials by comparing costs and revenues by addressing the deployment of different RES technologies. One finding is that heat generation causes 91 % of CO2 emissions making it the major producer. However, with the designed solution, emissions could be reduced to a third.

Dependence sandy soil thermal conductivity on grain-size composition

The development of renewable energy sources technologies is relevant. Sun radiant energy, wind energy, water energy, earth low-potential energy are main renewable energy sources. Energy foundations are used for earth low-potential energy extraction. The research results this paper presented can be used for energy foundations calculations. It is necessary to know soil thermal characteristics to the energy foundations calculations. At the moment, there are many calculation methods for determining soil thermal characteristics, but none of them take into account their grain-size composition. The research purpose is to assess the dependence sandy soil thermal conductivity on grain-size composition. According to the research results, firstly, the influence of the density and moisture content of the soil on its thermal conductivity was confirmed, and secondly, it was established that, at the same moisture content and density, the size of the soil grains matters. Particle size distribution affects the sandy soil thermal conductivity. With an increase in the particle size, sandy soil thermal conductivity increases.

Analysis of the Return on Investment in Solar Collectors on the Example of a Household: The Case of Poland

Background: The growing consumption is what drives the development of unsustainable energy and material-intensive production technologies that emit large quantities of pollutants into the atmosphere, water, and land. Obtaining green energy allows reduction of the interference with the environment and, consequently, fits into a sustainable energy development strategy. In order to achieve the emission targets set by the EU for Poland, it is necessary to prioritize the development of renewable energy sources (RES) technologies within the energy sector.Methods: The purpose of the study was to present the results of the research relating to the return on investment of solar collectors for single-family houses in Poland. The research was presented on the basis of the legal conditions applicable to micro installations in the light of the amendment of the RES Act, and the impact of these amendments on the aspects of such investment was determined.Results: On the basis of the constructed economic model used to assess the return on investment of increasing the area of solar collectors, it has been shown that an operating installation will bring measurable economic benefits in the form of reduction in the amount of energy purchased annually in the amount of 6,756 kWh and environmental benefits in the form of reduction of carbon dioxide emissions to the atmosphere 2.4–3.6 Mg per year. An installation subsidized under the “My Electricity” program can reach an NPV of EUR 6,000 over 20 years at a discount rate r = 0 and assuming that the electricity is EUR 0.15/kWh. If the price rises to 0.2 EUR/kWh, the NPV will be 10,000 EUR. For the analyzed installation, the investment consisting in increasing the collector area in accordance with NPV is economically effective for the absorber area in the range of 5.6–7.6 m2 and reaches the maximum value for the absorber area of 6.6 m2, while the absorber area above 7 m2 contributes to reduce the value of the economic return on investment. The obtained results have been generalized, which allows to use them in the process of selecting the size of collector area for similar installations.Conclusion: The return on investment analysis carried out in respect of a detached house allowed to demonstrate that this project is fully justified. Furthermore, pursuant to the Renewable Energy Sources Act in force in Poland, treating a small entrepreneur as a prosumer who may generally take advantage of favorable conditions for discounting the produced energy leads to very favorable possibilities of settling electricity. Considering an entrepreneur as a prosumer who may use one-off depreciation of a solar collectors installation as a fixed asset and request for VAT refund is what makes such an investment very attractive in financial terms and makes it difficult to find a safe investment alternative characterized by such a high rate of return.