Available Renewable Energy Resources Research Articles

Enhancing Islanded Power Systems: Microgrid Modeling and Evaluating System Benefits of Ocean Renewable Energy Integration

The energy transition hinges on the effective integration of renewable energy sources into the power grid. Islands can provide invaluable insights into the challenges and opportunities of integrating variable renewable energy into the grid due to their relatively small power systems, isolated grids, and diverse availability of renewable energy resources. This paper presents a study on the system benefits and challenges of marine energy integration in insular power systems, focusing on the Orkney Islands as a case study. A microgrid modeling approach that optimizes the mix of renewable sources and energy storage systems for future scenarios considering strategic time horizons (2030, 2040, and 2050) was employed. Results suggest that integrating ocean energies, namely, wave and tidal energy, yields notable benefits compared to traditional renewable energy sources exclusively. These benefits encompass reduced installed capacity, minimized energy storage requirements, lower excess generation, and overall cost-saving.

Hydrothermal synthesis of ZnO@MoTe2 nanocomposite as excellent electrocatalyst for hydrogen evolution reaction (HER)

The comprehension of novel fundamental inquiries about the design of electrocatalysts is of paramount importance in enhancing the availability of renewable energy resources and advancing the progress of exceptionally durable and effective nonprecious electrocatalysts for the process of water splitting. Enhancing the capacity of renewable energy storage systems through the usage of nonprecious nanocomposites for efficient H2O splitting holds the potential to foster a more sustainable and environmentally conscious society, hence mitigating the impact of global warming. The nanocomposite exhibits proficient catalytic kinetics for the HER process owing to the enhanced accessibility of MoTe2′s most active zones. The physical property of the nanocomposite was established through in-process characterization using different analytical techniques. In a basic environment, the ZnO@MoTe2 combination exhibited a significant value for the generation of hydrogen using electrocatalysts based on ZnO@MoTe2, which was a 34 mV dec-1 Tafel slope. The nanocomposite exhibited a higher turn-over frequency rate (TOF) of 2.4 s−1 than pure materials. The ZnO@MoTe2 nanocomposite displays a higher surface area of 1125 cm2 and a low Rct value of 93 Ω. The electrocatalyst exhibits exceptional stability and durability. During 50 h in an alkaline environment, the application of chronopotentiometry reveals no substantial decrease in potential. The utilization of nanocomposite based electrocatalysts has been shown to provide efficient quick charge kinetics, a noteworthy observation. The results of this study offer a novel, reliable and effective electrocatalyst that has potential applications in the advancement of electrocatalytic devices for hydrogen gas (H2) production. These devices can be developed employing cost-effective technologies and naturally occurring materials widely available worldwide.

On the behavior of renewable energy systems in buildings of three Saudi cities: Winter variabilities and extremes are critical

Integration of renewable energy systems emerges as a key enabler for future low-carbon electricity supply. To maintain a secure and effective supply, the design and operation of these systems must carefully account for the influence of weather variability on the availability of renewable energy resources and on energy demand. This study examines the impact of weather variability on the optimal design and operation of renewable energy systems for office buildings in Saudi Arabia. The building electricity demand is supplied by a photovoltaic/wind/battery storage system, with an additional connection to the grid. The optimization process then aims at finding the optimal capacities of the renewable energy system components, so as to strike a trade-off between life cycle cost and CO2 emissions by considering weather datasets with different levels of variability. The results show that accounting for the full weather variability, particularly the extreme weather events, leads to higher investment costs in fully renewable energy system, namely due to increased battery storage (up to 288%). Neglecting extreme events at the design stage, however, leads to a significant performance gap that could be compensated by grid integration, which adds to the overall CO2 emissions, for a negligible change in the system cost. Such extreme weather events are then associated with cloudy and high temperatures days, the impact of which drives down the photovoltaic power output and increases the demand for energy from the grid or from the storage. The study further examines the electricity price impacts on renewable energy system design and operation. With global weather variability challenges at the forefront, the paper findings draw insightful recommendations related to energy policy.

Design of an isolated renewable hybrid energy system: a case study

In addition to the fact that most renewable energies such as solar and wind energy have become more competitive in the global energy market, thanks to the great development in conversion technologies, it believes that renewable energy can play a crucial role in global environmental issues. However, in Palestine, the situation is different from anywhere else; renewable energy is not only an economic option, but an absolute necessity to get out of the energy crisis that Palestinian cities suffer from long years ago and continue nowadays. The cornerstone of the present research is focusing on the availability of renewable energy resources in Jenin Governorate (JG)—West Bank (WB)—Palestine. Two-year time-series of hourly solar, wind, biomass, and 1-year hourly electrical load data are used in the analysis in this paper. The energy potentials were estimated using System Advisor Model software (SAM), and the optimum combination and sizing of the hybrid renewable energy system were determined using Hybrid Optimization of Multiple Energy Resources (HOMER). The proposed Hybrid Renewable Energy System (HRES) consists of an 80 MW PV solar field, 66 MW wind farm, and 50 MW biomass system with an initial investment of $323 M. The proposed HRES generates 389 GWh/yr and is enough to meet 100% of the electrical demand of JG (372 GWh/yr) with excess in electricity generation of about 4.57% and the unmeet electric load is about 109.6 MWh/yr which is equivalent to less than 2 h off in a year. The estimated Levelized Cost of Energy (LCOE) was found as 0.313 $/kWh.

Multi-criteria decision analysis for evaluation of potential renewable energy resources in Malaysia

Switching to renewable energy resources as an alternative is critical for developing countries in order to ensure energy security and diversify their energy supply. Malaysia is endowed with biomass, solar, waste-to-energy, wind, and hydro energy potentials, although these have not been fully explored. This is because the country continues to rely extensively on conventional fossil-fuel energy sources such as coal and petroleum to generate power and consume energy. On the other hand, demand for energy is increasing as a result of population growth and a booming economy. Thus, this study intends to identify suitable potential renewable energy resources that can benefit Malaysia by analysing the outcomes of Focus Group Discussions (FGD) using the Analytic Hierarchy Process (AHP) as an analytical technique. Five renewable energy resources were evaluated: biomass, solar, waste to energy, wind, and hydro energy while five criteria were identified: carbon production, operational costs, location characteristics, energy, and availability of renewable energy resources. The outcome suggested a strategic focus on solar energy for Malaysia due to consideration in carbon production. This information will assist decision-makers in strategizing the most suitable renewable energy resources for Malaysia.

Performance Estimation and Control Analysis of AC-DC/DC-DC Hybrid Multi-Port Intelligent Controllers Based Power Flow Optimizing Using STEM Strategy and RPFC Technique

The control system will measure the renewable energy generation power, and if the generated power is equal to the grid power, the generation sources are directly connected to the load system. When the power generation is not at sustaining level, the controller will optimize the source using the DC-DC converter and Battery based Energy management system. The operation of the battery system depends upon the power generation availability of renewable energy resources. During the high power RES, the battery is charging condition. When the RES is low power means the battery is in discharged condition. Also, the fuel cell-based energy compensation will take place when the battery power is low. The Energy router will monitor all the above generation plants based on the threshold values of each power plant, substantial Transformative Energy Management (STEM) Strategy and Resilient Power Flow Control (RPFC) controller takes necessary action like which power plant is connected to the grid power system. The simulation is performed on Mat lab / Simulink simulation platforms, and the results show the effectiveness and reliability of the control strategy for micro-grid interconnection and flexible energy flow correspondence.

Power policies, challenges, and recommendations of renewable resource assessment in Pakistan

Pakistan is a developing nation that emphatically needs low cost energy resources to cope up with the economic growth. The major portion of energy is being generated by conventional methods. To generate energy through conventional methods is an expensive business that has direct impact on socio economic conditions corresponding to the rising of prices of energy in Pakistan. Another major implication of generation of energy by conventional source is increasing of circular debt that crossed Rs: 10 billion. The objective of this paper is to assess the potential of renewable energy resources and role of Government in policy formulation. The assessment showed that there is large availability of renewable energy resources. However, the formulated renewable energy policy does not have effect on the practical realization of renewable energy. This research study provides further insight owing to power policies, renewable energy transition and challenges of renewable energy policy facing in Pakistan. After potential assessment of renewable energy resources, the recommendations have been put forwarded that would help to promote renewable energy, as a key indicator in the sustainable growth and accelerating the energy transition to future energy perspectives of country.

Design Optimization and Comparative Analysis of 100% Renewable Energy Systems for Residential Communities in Typical Areas of China When Considering Environmental and Economic Performance

A 100% renewable energy system (RES) satisfies a user’s energy demand using only renewable energy, which is an important energy supply in China given that the government aims to realize carbon neutrality by 2060. The design and operation of 100% RESs in different areas would vary significantly due to the impacts of climates and geographical features. This study aimed to investigate the economic and environmental performance of 100% RESs for residential communities in different areas of China. In total, 30 typical cities were chosen based on the climate characteristics and the availability of renewable energy resources. The genetic algorithm was selected to obtain the optimal design of the 100% RES in each area by taking the minimum total annual cost and the minimum CO2 emissions as optimization objectives. The results showed that 100% RESs were dominated by solar energy and biomass. The investment could be recovered in 8 years if the economic performance was optimized in most areas, but the payback period became longer when the 100% RES was optimized when considering environmental performance. The emissions could be reduced by 86–99% for CO2 and 64–97% for NOx. The results of this study would provide data support for the investment of 100% RESs in rural or suburban areas of China.

Techno-economic and exergy analysis of tank and pit thermal energy storage for renewables district heating systems

Large-scale thermal energy storage (TES) emerges as key for the expansion of renewables-based district heating (R-DH) as it is able to bridge the seasonal gap between the heating demand and the availability of renewable energy resources (e.g. solar energy). This work develops a framework for techno-economic analysis considering several key performance indicators (e.g. energy efficiency, exergy efficiency). As TES systems integrated in DH are typically stratified, the work also examines the TES by means of stratification number and efficiency. The economic feasibility of the TES options is examined via the TES specific investment cost. Then, the work recommends the levelized cost of stored heat (LCOS) as a practical measure for the TES techno-economic feasibility. The outcomes show that the tank has higher performance in terms of efficiency indicators (energy and exergy) and stratification measures, but it is characterized with high specific cost. Yet, the tank LCOS is lower compared to that of the shallow pit due to its low performance and despite its low specific cost. Thus, in order to take advantage of the tank's better performance and shallow pit's lower specific cost, the work proposes a third TES geometry called as hybrid TES that combines both tank and shallow pit. The results reveal the potential of this geometry as it arises as a promising option. Furthermore, the results indicate that the transition to low-temperature R-DH brings technical and economic advantages as the LCOS tends to be lower compared to that of TES installed in high-temperature R-DH. Moreover, the work reveals that due to the importance of increasing the economic feasibility for large-scale TES, it is of crucial to develop new materials and construction methods to ensure cost-efficient insulation of the buried TES.

Net zero energy barns for industrial egg production: An effective sustainable intensification strategy?

Net zero energy buildings (NZEBs) are energy efficient buildings that incorporate renewable energy generation systems so as to produce sufficient renewable energy to at least offset the total amount of non-renewable energy used by the building on an annual basis. NZEB technologies have widespread commercial and residential application, but their feasibility and efficacy in the livestock sector in support of sustainable intensification have received little attention. This study quantifies the potential for such technologies to improve sustainability outcomes in the livestock sector based on an ISO 14044-compliant life cycle assessment of a pilot net zero energy laying hen facility in Alberta, Canada compared to a conventional facility. It was found that direct energy inputs account for 6.47% and 31.64% of the life cycle cumulative energy use of egg production in NZE and non-NZE hen housing, respectively. Average infrastructure-related contributions to the life cycle impacts of egg production are only 4.34% and 1.94% for the NZE and non-NZE barns, but NZE technologies reduce the net impacts of egg production by 0.89–64.82%. The environmental impact payback time for the NZE barn (30-year lifespan) ranges from 1.38 to 20.66 years, considering the largely fossil fuel-based electricity grid in Alberta, which indicates that non-trivial environmental benefits would accrue across impact categories considered. However, this could vary considerably elsewhere depending on the types and amounts of green energy utilized in regional grid mixes. The type and availability of renewable energy resources that are integrated into NZE barns will similarly be important in determining the potential of such technologies to support sustainable intensification in this sector.

Racial formation, coloniality, and climate finance organizations: Implications for emergent data projects in the Pacific

This commentary explores the potential consequence of latent racial formation in emergent climate finance data projects and draws from ethnographic research on climate finance governance conducted in Fiji. Climate finance data projects emerging in the Pacific aim to ease the flow of finance from the Global North to the South. These emergent data projects, such as renewable energy resource availability and investment mapping, are imbedded in the climate finance organizations that fund, develop, and use them. Thus, the commentary explores climate finance organizations through the lens of Ray’s (2019) theory of racial organizations, highlighting the ways in which important climate-related resources are mediated through racial and colonial schemas. The racial mediation of two key resources are spotlighted in this discussion: the finance itself and knowledge. Given that the Pacific region is at the coalface of climate change’s existential effects, the just allocation of resources is imperative. In interrogating the ways in which emergent data projects may deny these resources based on hidden racial schemas, the paper cautions against new and old forms of colonization that may be mobilized through even well-meaning techno-benevolent fixes ( Benjamin, 2019 ).

Modeling Wind-Turbine Power Curves: Effects of Environmental Temperature on Wind Energy Generation

Global warming represents a serious challenge, which requires the adoption of renewable energy technologies worldwide. However, it can negatively affect the availability of renewable energy resources, such as wind, which are needed for electricity generation. In this context, there is an increasing need for more accurate evaluations of wind turbine power curves. A novel methodology to model the power curves of wind turbines, which combines the use of artificial neural networks (ANN) and Fuzzy logic rules, is proposed in this paper. This methodology assesses the role of environmental temperature in the power curve and the impact of temperature increases on wind energy production. The application of this methodology is illustrated with the simulation of the impact of global warming on the electricity generation of a wind farm. Due to the non-linear relationship between the power output of a turbine and its primary and derived parameters, it is shown that ANN combined with an expert system formed by a Fuzzy logic module fit power curve modeling processes well. The application of the methodology shows that an increase in temperatures would trigger a small reduction in the performance of wind turbines.

Site-dependent levelized cost assessment for fully renewable Power-to-Methane systems

The generation of synthetic natural gas from renewable electricity enables long-term energy storage and provides clean fuels for transportation. In this article, we review the economic challenges for synthetic natural gas and introduce a high-resolution optimization model for decentralized Power-to-Methane plants. The model optimizes both the system layout and its operation including renewable power generation. The optimization yields the levelized costs per kWh of synthetic natural gas. We find that costs vary between 0.24 and 0.30 €/kWh depending on the local availability of renewable energy resources. The optimum renewable generation mix typically features much more wind than solar power, and the use of battery electric storage systems has only minor effects on levelized costs. We further discuss how the economic competitiveness of Power-to-Methane systems can be improved by the technical developments and by the use of co-products, such as oxygen and curtailed electricity.

Setup and testing of smart controllers for small-scale district heating networks: An integrated framework

Nowadays, the growing availability of renewable energy resources is an opportunity to reduce carbon emissions but also a challenge, as advanced control technologies are required. The new generation of smart district heating and cooling networks, for instance, pledges efficient energy distribution, flexibility and low-carbon energy integration. However, in the literature it is hard to find comprehensive frameworks for the integrated setup and testing of smart control strategies. This paper defines and demonstrates a framework that involves all steps of the controller development for small-scale district heating networks: from conceptualization to prototype testing. The innovative controller prototype, which relies on Model Predictive Control and aims to minimize operating costs and/or energy, is demonstrated in three original case studies, one in a simulation environment and two in real systems of different complexity in operational conditions. Compared to the control approaches previously adopted, based on predefined rules and operator experience, the smart solution achieves 6% reduction in cost and up to 34% reduction in energy consumption while meeting user requirements. The fast replicability of the proposed integrated methodology can foster the transition toward the next generation of smart heating networks.

Act locally, transition globally: Grassroots resilience, local politics, and five municipalities in the United States with 100% renewable electricity

This paper examines five communities in the United States (U.S.) that have transitioned to 100% use of renewable resources for electricity. The paper describes and compares social, political, and economic similarities and differences among these communities to improve understanding of the factors that support successful renewable energy (RE) transitions. The analysis builds on Geels’ multi-level perspective theory in assessing sustainable energy transitions and the energy transition process based on these five case studies. Main variables of interest considered for 100% renewable energy transition in these municipalities are renewable energy resource availability (solar, wind, and hydro), utility ownership, partisanship of municipal leadership, population size, and supporting energy legislation at state level renewable portfolio standard (RPS). Findings from this paper show that utility ownership appears to play a critical role in the transition process, as most of the municipalities have municipally owned utilities. State RPS programs are also prominent among all the states in which these the municipalities are located, indicating the importance of state legislation. Further, RE resource availability may not be required, as possibilities for hybridization of energy technologies are evident in the studied places. The most common pathway typology in these 100% RE transitions is reconfiguration. This typology results from technological innovations fuelled by development in RE technologies and stakeholder advocacy. Identified drivers from this research provide helpful parameters of consideration for energy transitions in other places in the U.S. and beyond.

Mapping Flexibility of Urban Energy Systems (FIRST) project: Rationale and study design of an exploratory project

With the publication of the new Energy Performance of Buildings Directive, a large number of buildings are expected to become high energy performance and explore more the availability of renewable energy resources. Such buildings are often described in literature as nearly Zero-Energy Buildings (nZEB). Because renewable energy sources, such as wind and solar power, have an intrinsic variability, the zero-energy annual balance of nZEBs is difficult to reach at short time resolution (e.g. hourly). Thus, since electricity generation from small-scale solar renewable (typical case in Portugal) in individual households has limited capacity to be adjusted according to the power system needs, it is relevant to consider the demand flexibility potential, specially at community level (cluster of buildings). Unfortunately, there is a lack of studies on the impact of changes in electricity use at urban level on the future energy systems. Therefore, an approach addressing the energy flexibility (EF) in buildings may allow obtaining useful exploratory directions for the construction sector and related markets, policy makers and regulatory bodies. For these reasons, an exploratory project aimed at examining the potential of EF at the level of an existent neighbourhood in Lisbon was initiated. In this article we describe the objectives, design, and methods of the FIRST project, designed to map out the potential for EF in terms of benefits and costs in Lisbon.

Assessment of on-site steady electricity generation from hybrid renewable energy systems in Chile

Chile has an immense renewable energy potential but its integration into the energy system constitutes a major challenge. The country has a complex topography that is expressed by a divided national grid with almost isolated subsystems and wide differences in the availability of renewable energy resources. The present study aims at evaluating the potentials of combining solar power, wind power and storage systems to provide steady loads already from the generation source. The analysis relies on an optimization model to size hybrid renewable energy systems and 10 years of weather data from the brand new ERA5 global reanalysis. Multiple scenarios are calculated and intercompared for all possible locations across the country. These scenarios include system sizing considering hourly weather data for the period 2008–2017 and for one year without major weather extreme events. In both analyses, the results are calculated for systems that generate 1 MWh of electricity at every time step and systems that have certain intraday flexibility. Results show that the necessary generation and storage capacities to provide a steady energy output are very high even for areas with exceptionally high renewable energy potential (in the Atacama desert the system configuration requirements could reach 10 MWp of photovoltaics and 10 MWh of storage). Intraday flexibility has direct effects on these results by reducing the total size of the systems but the effects on the sizes of the installations of the particular technologies depend on the individual geographical location.

Assessment of Decentralized Electricity Production from Hybrid Renewable Energy Sources for Sustainable Energy Development in Nigeria

Abstract This paper presents technical and economic assessment of a hybrid energy system for electricity generation in rural communities in the six geopolitical zones of Nigeria. The study was based on a 500 rural household model having an electric load of 493 kWh per day. To simulate long-term continuous implementation of the hybrid system, 21 years (1992 – 2012) hourly mean global solar radiation and wind speed data for the selected sites were used. The mean annual wind speed and solar radiation for the locations ranged from 2.31 m/s for Warri to 3.52 m/ s for Maiduguri and 4.53 kWh/m2 for Warri to 5.92 kWh/m2 for Maiduguri, respectively. These weather data were used for simulation with the Micro-power Optimization Model software HOMER. From the optimum results of the hybrid system,Warri has the highest NPC and COE of $2,441,222 and $0.721/kWh, respectively while Maiduguri has the least NPC and COE of $2,225,387 and $0.658/kWh, respectively for the 21 years project lifespan. The high value of COE for Warri is due to its low renewable energy resource while low COE for Maiduguri is due to its high renewable energy resource. The Northern part of the country has ample renewable energy resource availability and with a strong political will, optimal utilization of these renewable resources (solar and wind) can be actualized. Researchers, Industrialists, Policy Makers and the Nigerian government should therefore seize this opportunity in developing a sustainable energy through utilization of abundant renewable energy resources in the country.

Size Optimization and Sensitivity Analysis of Hybrid Wind/PV Micro-Grids- A Case Study for Bangladesh

This paper presents a feasibility and sensitivity analysis of renewable energy-based off-grid and grid-connected microgrids by investigating the potentials of wind and solar energy at different areas, namely, Kuakata, Sitakunda, Magnama, Dinajpur and Rangpur in Bangladesh - a country that experiences a tropical climate. A specialized neural network algorithm has been employed to track the wind speed and solar irradiance all year round in two salient regions and the promising results have been analyzed for making the decision whether the data are reliable for forecasting or not. Four different types of models including PV-Grid, Wind-Grid, Wind-PV-Grid, and off-grid hybrid renewables are designed using the Hybrid Optimization of Multiple Energy Resources (HOMER Pro) software. By considering the key factors: net present cost, cost of energy, renewable fraction, local load demand, availability of renewable energy resources, system economics and greenhouse gas emissions, the optimal hybrid renewable energy system (HRES) configurations (Wind/PV/Grid/Battery) for the mentioned regions are determined. Various sensitivity and optimization variables, such as RE resources, local load demand, grid energy price, nominal discount rate, the life-time of wind turbine, the capacity of wind turbine, PV arrays, converter, and battery are used to make the decision. Detailed sensitivity analyses are performed to investigate how the optimal system configurations change with a tiny variation in input variables and results show output results are more sensitive on the variations in long-term average wind speed and solar irradiance, nominal discount rate, and the lifetime of wind turbines than the other inputs which is definitely a vital finding of this investigation. Finally, considering several decision making factors, a detailed feasibility chart is presented for two distinct nominal discount rates, i.e., 9% and 10%, which depicts the economically viable renewable energy based plant size in the mentioned regions. Although the crux of this paper is based on providing low-cost electricity to people living in rural areas of Bangladesh, our propositions carry with them certain concomitant benefits, not least of which are environmental and social benefits.

Grid Secondary Frequency Control by Optimized Fuzzy Control of Electric Vehicles

The major debates on environmental pollutions, abundant availability of renewable resources, scarcity of fossil fuel resources in certain parts of the world, and geopolitical conflicts have underscored the need for promoting the use of renewable and distributed power generation. Since the availability of renewable energy resources, such as wind energy depends on variable atmospheric conditions, a massive integration of renewable energy would require additional reserves to compensate the power deficiency for supplying loads. However, the increasing use of electric vehicles (EVs) along with their charging demands can apply a significant amount of load to the power grid, which can cause stability concerns if not control properly. In this paper, EVs charges are applied to the secondary frequency control and an optimized fuzzy controller is considered to compensate the variable unbalances between demand and generation. To verify the performance of the proposed control method for reducing frequency deviations, several case studies are considered in this paper and simulations are carried out in MATLAB/SIMULINK environment. The simulation results illustrate a good performance of proposed method.