Simulation Of Energy Systems Research Articles

Large-Eddy Simulation of airborne wind energy systems wakes

Wind energy is usually harnessed using wind turbines but it is not the only way of collecting this energy. In this paper, Airborne Wind Energy Systems (AWES) are considered. The understanding of the wake shed by such devices is of primary importance when considering farms, yet it has not been much studied so far, and even less so when considering kites with soft curved wing. In this work, LES is used to analyse the wake of AWES. Two types of wings are considered: a straight wing, modelling the reference rigid wing AWES and a curved wing accounting for leading edge inflatable kites. Both types of wings are modelled using actuator lines. The wake analysis reveals that the wake of curved wings tends to be stronger and to recover faster. For the case of the tilted trajectory, asymmetries in the wake are also noted. The difference is explained by the azimuthal variation of the circulation distribution on the wing. It also relates to some wakes characteristics for tilted wind turbines. The wake of the curved wing is also more sensitive to the variation of the loading when it flies tilted trajectory, due to the varying loading on its tips.

Wind characteristics of Tamil Nadu coast towards development of microgrid - A case study for simulation of small scale hybrid wind and solar energy system

Wind's intermittent nature poses a considerable challenge for an effective microgrid design, particularly in “Island mode.” The objective of this research is to investigate the wind characteristics of a coastal location in Tamil Nadu, India, with a special emphasis on wind consistency, to establish a successful microgrid at the site. The research was based on wind data acquired from an 80 m high meteorological mast established in Manamelkudi, Pudukkottai District, Tamil Nadu, India, from January to December 2017. Based on the analysis, it is observed that, while being within the moderate wind potential regime, the region has a substantially stable wind pattern when compared to the in-land windy places. According to the assessment, the site is expected to effectively complement solar generation, with 74% of its wind generation occurring between 06:00 p.m. and 06:00 a.m. Considering the consistency of wind and the complementary nature of solar generation, the Manamelkudi location is considered to have promising potential for the development of microgrid systems using wind and solar hybrid power. The investigation demonstrated that the geography of the site plays a critical role in the consistent wind pattern of the Manamelkudi site.

Assessment of green hydrogen production in Morocco, using hybrid renewable sources (PV and wind)

Water electrolysis coupled with renewable electricity systems is one of the most promising ways that will contribute to making the energy transition toward zero carbon emissions possible. This study aims to perform a technical-economic analysis of large-scale hydrogen production facilities through the simulation and optimization of hybrid renewable energy systems that use wind turbines and photovoltaic panels. Five Moroccan cities are subjected to the approach. The PV/wind ratio, net present cost, Levelized cost of hydrogen, storage capacity, and water desalination cost are analyzed. The results show that combining photovoltaic panels and wind turbines helps produce low-cost hydrogen in Morocco, especially in Dakhla with 2.54$/kg. It's the lowest cost in Morocco compared to previous studies. The results also show the importance of using hydrogen tanks to store energy. Finally, the cost of water desalination can be neglected, as it only represents between 0.12% and 0.35% of the net present costs.

Design of International Airport Hybrid Renewable Energy System

This paper presents the design and simulation of a hybrid renewable energy system utilizing solar and wind energy sources with a backup generator. The demand for reliable electric energy in support of investments in large social and economic development activities such as airport operations has been an agenda worldwide. In Tanzania, Mwanza International Airport (MIA) expects to consume about 18 MVA of electric power annually to support its operations for the next 25 years. About 78-80% of the world's commercial energy comes from fossil fuels. Non-renewable fuels and other negative effects contribute to global warming through greenhouse gas emissions and carbon dioxide emissions. Additionally, most centralized conventional power generation methods require transmission systems, adding complexity and poor power quality. Therefore, the proposal to use a mixed-coupled hybrid renewable energy source to power the airport is necessary. The energy mix considered is solar photovoltaic (PV), wind, diesel generator and a battery. There is an average solar irradiation of 5.38 kWh/m2 and a wind speed average of 4.20 m/s that could be converted to electricity by installing a 10-kW wind turbine (this is enough to generate power for MIA). The diesel generator and the battery designed at 140 kVA and 400 Ah, respectively, take the intermittency. The project will be in operation for 25 years; hence its costs are reasonable, and the justification is the potentiality of harvesting that estimated energy output of 18 MVA, which will meet the load for MIA. Some mathematical computations were performed, and, in the end, simulation results displayed different techno-economic Hybrid Renewable Energy Source (HRSE) configurations. The selected system's complete design would include a 78.48 kW PV system comprising 314 pieces of 200 W poly-crystalline modules, 608 batteries of 83.4 Ah, 12 V rating, 140 kVA diesel generator, and 41.64 kVA bidirectional converter. The net present cost of the selected design is US$357,780.8, the energy cost is 0.93US$/kW, and the minimum renewable fraction is 40.2%.

Indoor Climates and Energy Consumption by Air Conditioning System in a Learning Resource Centre in Malaysia

A Learning Resource Centre is a type of library that houses books and all other media facilities as well as daily newspapers and journal articles. Indoor climates such as the indoor dry bulb temperature and relative humidity must be controlled at the recommended level in a Learning Resource Centre in order to keep the collections and archival materials in good condition. Based on the ASEAN Energy Organization report, 50-60% of the total energy consumption of a building goes to Heating, Ventilating and Air Conditioning (HVAC) systems operation. As such, energy savings for HVAC systems is crucial and should be studied, especially after climate change has taken place. In this paper, the author installed data loggers in the Resource Centre for a period of a month to monitor the indoor climate changing trend. Due to the lack of cooling and dehumidification processes when the HVAC systems were turned off, there were peaks in both indoor dry bulb temperature and relative humidity during the night. The ambient high relative humidity had caused an increase in the indoor relative humidity at night. At the same time, the energy consumption simulation of the HVAC systems was run using the Transient Energy System Simulation Tool (TRNSYS). Different operating modes were set in the simulations to obtain the comparison of energy consumption for the different operating modes of the HVAC systems under four different weather elements, namely the present-day, 2020’s, 2050’s and 2080’s time scenarios. Electricity bills for the different scenarios based on current electricity tariffs were analyzed. The results show that a significant saving can be obtained if the HVAC systems were operated under the All-day Operating Mode.

Modelling and Simulation of the Hybrid System PV-Wind

In this paper, we focused on modeling and simulation of a hybrid solar-wind energy system, consisting of a photovoltaic cell and a wind turbine driven by a Permanent Magnet Synchronous Generator (PMSG). The proposed system gives details of the hybrid solar-wind system. In the PV subsystem, there will be a photovoltaic energy subsystem, MPPT controller, and a DC-DC boost converter. The wind turbine subsystem includes a wind turbine energy subsystem, PMSG, and MPPT controller. The MPPT controllers were designed to extract the maximum power regardless of the weather conditions and temperatures. The P and O algorithm is introduced in the MPPT used in the PV energy subsystem and on the control of the machine side converter (MSC). The proposed wind turbine energy subsystem is based on Direct Torque and Flux Control (DTFC). The simulated results are demonstrated to show that the hybrid solar-wind generating system can realize a maximum power point tracking control of wind and solar power to satisfy the energy demand over an extensive range under unpredictable atmospheric conditions. The system has been demonstrated by MATLAB/Simulink and tested for variable weather conditions and temperatures.

Analysis of the impact of offshore wind power on the Japanese energy grid

<abstract> <p>As part of its economy-wide decarbonization target towards 2050, Japan plans to increase renewable generation, especially offshore wind, for which the country has a high potential. However, this resource is currently under-developed as available turbines are prone to shut-downs and can even suffer damage during the passage of typhoons. With new typhoon proof (T-class) turbines being currently developed by various companies, Japan now aims to develop 10 GW of offshore wind between 2021 and 2030, and 91 GW in the long-term. This research estimates the impact of integrating offshore wind into the Japanese main power grid using T-class turbines by considering three scenarios. First, a business-as-usual (BAU) case with 10 GW offshore wind capacity (following the 6<sup>th</sup> Strategic Energy Plan of Japan). Second, an offshore wind capacity of 91 GW. Third, the 91 GW offshore capacity being redistributed amongst regions to maximize its integration opportunities (Scenario 2). The simulations were carried out using the Energy System simulation model (EnSym). The results show that the BAU and Scenario 1 resulted in offshore wind achieving 1.7% and 7.28% of generation share, respectively, increasing to 9.77% for Scenario 2. Increasing the share of offshore wind in the energy mix mainly replaced liquefied natural gas (LNG).</p> </abstract>

Simulation of a Cellular Energy System including hierarchies and neighborhoods

The massive use of small energy resources and storage units causes a transition from a traditionally centralized to a decentralized energy system. To structure and coordinate the emerging changes in the energy system, the concept of Energy Cells (ECs) was developed. Several ECs can be combined to form a hierarchically superordinate EC. These hierarchically superordinate ECs can in turn be combined and thus form a complex hierarchy. An EC encapsulates coherent parts of an energy system and can communicate as well as exchange energy with other ECs at a different or the same level. It follows the idea of local balance of energy provision and demand. A network of ECs forms a Cellular Energy System (CES). In this paper, we develop a concept for modeling and simulating a CES. We accomplish this by beginning with atomic components like consumers, producers, and storage units and aggregating them with Hierarchical Controllers (HCs). Such a hierarchically structured energy system is part of various proposals. However, we are able to add neighborhood relations by introducing Local Controllers (LCs). This is more realistic and also opens many degrees of freedom for control strategies in such a system. Following the recursive structure of the CES itself, we define recursive functions for visiting the CES architecture and realizing various control strategies. We evaluate our approach in a series of partially randomized scenarios, showing notable differences in the performance of the CES regarding different control strategies in a larger example. We also provide a theoretical analysis of the computational complexity of the suggested approach.

The Economic Feasibility of using Renewable Energy in Iraqi Oil Fields

This study included over all about competition of renewable energy to the conventional energy, and the economic growth on the demand for renewable energy technology especially solar energy, and the increasing on its annual cost decline. Also, highlight on the most important projects applied in the oil fields in the Middle East and America.
 In this study, a design and economic simulation of the solar energy system was conducted as a source for generating electricity with a capacity of 1 megawatt and a comparison of the capital and operation cost between the solar energy system, diesel generators, government and private sectors stations at the same operating time and the same energy. The economic simulation has shown that there is a big difference between the capital costs, as the cost of the solar energy system is about (40-37%) higher than the cost of diesel generators and investment stations, respectively, for a maximum operating capacity of 1 megawatt/hour, but on the other hand, it is characterized by The solar energy system has a depreciation factor of 0.75% compared to its counterparts, which reaches 10%, and the standard of its energy cost is low, reaching 0.22 $/ kilowatt compared to other sources of energy. In addition, Payback period of the solar energy system was 9 years by saving fuel cost and its low operating cost that reach to 0.0183 $/kWh, compared to its counterparts from government sector station, diesel generators, power stations. (Fuel from the investor), and private sector stations (fuel from the investor), whose operating costs are (0.1, 0.076, 0.038, 0.1) $/kWh, respectively. The results showed that the solar system economically feasible, with lifetime 25 years, while the generator lifetime ten years only. The solar radiation system limits carbon emissions, as the amount of carbon emissions per kilowatt of energy using conventional fuels is (185-265) grams of CO2 per kilowatt.

A reliable energy system for Japan with merit order dispatch, high variable renewable share and no nuclear power

In the context of Japanese energy targets for 2030 and the long-term strategy towards zero carbon emissions by 2050, this study estimates the impact of several measures for increasing the renewable generation share while maintaining a reliable energy system. To do so, the authors attempted to reproduce the expected 2030 energy mix according to the 5th Strategic Energy Plan, and then formulated two different alternative scenarios: a European-style merit order dispatch in Scenario 1, and the replacement of nuclear generation with renewables in Scenario 2. The simulations were carried out using the Energy System simulation model (EnSym), which was newly developed by the authors. EnSym simulates the hourly generation of all major resources, including variable renewables, using meteorological data. Spatially, EnSym also simulates the electricity transmission grid of Japan, allowing to understand how changes in grid capacity, dispatch framework and energy policy can impact the overall system. The results show that merely switching to a merit order dispatch could increase the use of renewable generation by 1.5% (to 22.6%). Further, replacing nuclear power resulted in a renewable share of 58.2%, which would include 300 GW of solar PV, 45 GW wind, 36 GW biomass and 23 GW geothermal capacity (while leaving all other generating capacity constant at 2021 levels). Based on these results, the authors also provide recommendations for changes to the next, 6th, Strategic Energy Plan.

System sizing and transient simulation of a solar photovoltaic off-grid energy system in various climates with air heat pumps

Photovoltaic off-grid systems are essential in supplying power to areas remote from the grid. Mobile homes are used in various cases in remote areas, most of which are far from the power supply grid. It is not economically feasible to develop electricity networks in these areas. One of the best ways to supply power in such cases is to implement photovoltaic systems. These systems can produce electricity through solar irradiation and are environmental-friendly. However, due to the high capital cost of these systems, it is necessary to determine the optimal number of components, such as photovoltaic panels and batteries, to optimize the initial cost and achieve a desirable level of availability. In this study, the TRNSYS software is utilized to investigate the energy required by mobile homes for the ventilation system and power supply operation for different regions. A numerical method is developed to quantify the optimal photovoltaic system for each region for the optimal sizing of these systems. Also, generators have been considered in particular cases to ensure a continuous power supply. Finally, the cities are divided into different categories, showing the off-grid system performance in these regions. Results obtained for the city of Tehran, Iran, suggest that the Levelized energy cost is 0.23 USD/kWh. This system lacks 2.45%, equivalent to 118 h, of required energy and produces 56% surplus energy.

Online autonomous calibration of digital twins using machine learning with application to nuclear power plants

As a near-zero carbon emission energy source, nuclear energy plays an important role in the current world energy decarbonization scenario. Digital twin is a key technology for the continued development of nuclear energy applications. The digital twin requires real-time, high-precision simulations that are beyond the capabilities of current nuclear energy system simulation programs. Therefore, this study proposes an autonomous calibration method for the digital twin of nuclear power plants to compensate for the error in the results of the low accuracy digital twin that can run quickly to obtain higher accuracy results to meet both high accuracy and real-time requirements. The proposed method consists of offline and online stages. In the offline stage, digital twin simulations are first performed. The simulated data and corresponding measurements data (or real data) are used to build an error database, which will be used for the next step of data-driven model training. To reduce the complexity of calibration model, the error database samples are then grouped by clustering. Data-driven calibration models are built on each group based on the simulated data and errors. In the online stage, the digital twin runs in parallel with the nuclear power plant and receives real-time data. The calibration model is continuously updated using dynamic error database. The feasibility of the new proposed method has been demonstrated on measured data from the PKLIII B3.1 steam generator pipe rupture (SGTR) experiment. The results showed that the physical quantities such as pressure, temperature and mass flow rate were well calibrated during the 1000 s of parallel running. The R2 of all physical quantities including temperature, flow rate, and pressure are above 0.99.

MUSE: An open-source agent-based integrated assessment modelling framework

Integrated assessment models (IAMs) are a cornerstone of an effective approach to climate change mitigation. Despite the variety of methodologies for characterising the energy system, land use change, economics, and climate response, the modelling community has an open and urgent request for tools capable of more realistic interpretation of the energy transition, capturing human behaviour, and embodying the principles of transparency, reproducibility, and flexibility of use.This paper presents an open-source modelling framework designed to fill that gap. Named MUSE (ModUlar energy systems Simulation Environment), this new agent-based model supports flexible characterisation of agent decision-making, including individual goals, bounded-rationality, imperfect foresight, and limited knowledge during the decision process. MUSE integrates this agent-based approach in a partial-equilibrium framework and enables a technology-rich description of the energy systems with an unprecedented degree of flexibility for including technological, temporal, and geographical granularity. The structure of MUSE creates the ability to produce climate change mitigation assessments that are more grounded, and more tangible model outputs for conceiving effective approaches to mitigation. MUSE is available open source under a GNU General Public License v3.0 on GitHub at this link https://github.com/SGIModel/MUSE_OS.

Improvement pathways of vehicle fuel energy conversion based on energy flow experiment and system simulation

In this study, the energy flow of an internal combustion engine (ICE) vehicle is experimentally investigated in a climate chamber under Worldwide Light-duty Test Cycle (WLTC). Each part of the tested vehicle energy loss has been compared to the similar displacement of engine or type of transmission according to the database of conventional gasoline engine passenger car. Then, an integrated simulation model for the tested vehicle is established and calibrated. After that, some technological pathways have been taken for tested vehicle fuel saving by using the calibrated simulation model. The specific fuel saving technological pathways mainly include excess air coefficient improving, engine speed decreasing when the engine resumed fuel supply, engine coolant temperature improving, engine coolant temperature rise process improving, transmission oil temperature and rise process improving, engine idle speed decreasing and transmission gear in neutral position when the vehicle speed is 0, electrical accessories power reducing, and engine cold start speed decreasing. The fuel saving degree of above technological scheme is 0.57%, 1.37%, 0.25%, 0.38%, 0.53%, 2.34%, 0.61%, and 0.59%, respectively. At last, the effects of combinatorial technological scheme to vehicle is simulated and experimented, and the fuel saving degree of them is 5.63% and 5.92%, respectively.

An Open Digital Platform to Support Interdisciplinary Energy Research and Practice—Conceptualization

Energy research itself is changing due to digitalization and the trend to open science. While this change enables new research, it also increases the amount of, and need for, available data and models. Therefore, a platform for open digital energy research and development is required to support researchers and practitioners with their new needs and to enable FAIR (findable, accessible, interoperable and reusable) research data management in energy research. We present a functional and technological concept for such a platform based on six elements: Competence to enable researchers and practitioners to find suitable partners for their projects, Methods to give an overview on the diverse possible research methods within energy research, Repository to support finding data and models for simulation of energy systems, Simulation to couple these models and data to create user-defined simulation scenarios, Transparency to publish results and other content relevant for the different stakeholder in energy research, and Core to interconnect all elements and to offer a unified entry point. We discuss the envisioned use of the outlined platform with use cases addressing three relevant stakeholder groups.

The benefits of 4th generation district heating and energy efficient datacentres

This paper identifies the energy system benefits of transitioning district heating infrastructure from current 3rd generation district heating (3GDH) to 4th generation district heating (4GDH) with lower grid temperatures and more integration with other energy sectors. Previous papers have investigated the effect of going from 3GDH to 4GDH on a local perspective. In this paper it is investigated how this transition affects the energy system on a national level, where both the costs and energy effects are evaluated based on national hourly energy systems simulations including all energy sectors in a climate neutral energy system scenario. Moreover, the paper identifies the effects of different cooling solutions in datacentres. The analyses include effects on heat sources as well as the effect on the cost and losses in the district heating grid. This is done for the case of Denmark. In the case of Denmark, it is found that transitioning from 3GDH to 4GDH decreases the system cost by 220 M EUR/year, corresponding to 7 M EUR/TWh delivered heat at the end-user. Increasing the temperature outlet of datacentre waste heat has a value for the system as high as 52–59 M EUR/year, corresponding to 1.7–1.9 M EUR/TWh delivered heating at the end-user.

Wind-assisted, electric, and pure wind propulsion – the path towards zero-emission RoRo ships

ABSTRACT Electrical and wind propulsion, together with energy stored in batteries and renewable energies harnessed onboard, can lead the way towards zero-emission ships. This study compares wind propulsion solutions and battery storage possibilities for a RoRo ship operating in the Baltic Sea. The ship energy systems simulation model ShipCLEAN is used to predict the performance of the zero-emission ship in real-life operating conditions. The study showcases how ships can be transferred from a conventional, diesel-powered to a zero-emission ship. For the zero-emission ship, all energy needed for auxiliaries and propulsion is taken from renewable sources onboard or from batteries. Challenges and opportunities, as well as necessary adaptions of the route and logistics, are discussed. Results of the study present which wind propulsion technology is the most suitable for the example RoRo ship, and how the installation of suitably sized battery packs for zero-emission operation affects the cargo capacity of the ship.

Dynamic simulation and optimization of a novel energy system with Hydrogen energy storage for hotel buildings

In the current study, an innovative smart energy system based on hybrid solar-GT energies is proposed. Transient performance assessment and techno-economic analyses are conducted to evaluate the dynamic performance of the system. The system has three main parts: solar panels, a Hydrogen production and storage system and gas turbine system, a chiller, and several heat exchangers and auxiliary components. The goal is to set a stand-alone system to generate the need of the building, including heating, power, and cooling. The system is an off-grid system due to its energy storage system. The system is analyzed comprehensively from 3E standpoints. A parametric study of key design variables is performed, and optimization is carried out to find the best solution point. Results indicate that at the optimized point, the system reaches the effectiveness of 39.5%, the emission of 0.85 kg/kWh and the Levelized product cost of 0.051 $/kWh. Furthermore, increasing the pressure of the (absorption chiller) AC in the (gas turbine) GT cycle from 1.5 to 7.5 results in a sharp decline in net output work.

Energy System Optimization and Simulation for Low-Altitude Solar-Powered Unmanned Aerial Vehicles

The accurate calculation of energy system parameters makes a great contribution to the long-term low-altitude flight of solar-powered aircraft. The purpose of this paper is to propose a design method for optimization and management of the low-altitude and long-endurance Unmanned Aerial Vehicles (UAV) energy system. In terms of optimization, the power input and output generated by solar panels and cruise thrust are calculated, and the energy balance of the UAV during flight is analyzed. In addition, in order to meet the energy consumption requirements of UAV during day and night flight, the influence of local environmental conditions (such as morning and evening clouds and night interference) on the aircraft is considered, and the remaining time indicator is designed to ensure long-term flight stability. Battery capacity is also estimated by the remaining time. This paper will describe extended criteria for optimization and extension methods to improve the stability and robustness of aircraft flight performance for multiple consecutive days. In addition, a design method for the UAV has been developed, which simulates and optimizes the parameters of the solar-powered UAV so that it has a wingspan of 5 m and a relative battery mass of 3 kg. The simulation in this paper describes in detail the aircraft taking off from 7 a.m. on the first day to verify the aircraft’s full day and night flight capability, and achieving the aircraft’s long flight on 22 June to meet the mission requirements of multi-day flights. It also analyzed and verified the performance at the edge of the 48 h flight time window on 21 April, which differs from the lighting in August. Finally, a flight experiment was completed on 9 August. The feasibility of the proposed method and process is verified in this paper along with the performance of the designed UAV, which will provide more guidance for future work.

Optimal sizing and simulation of a sustainable off-grid hybrid energy system: A case study of the coastal areas of Delta State

The off-grid coastal areas of Delta State are rich in energy resources including natural gas and solar irradiation; but do not have access to electricity. Accordingly, this paper proposes a sustainable solution for power supply in these areas using the method of simulation. Specifically, using the Hybrid Optimization Model for Multiple Energy Resources (HOMER) software, the most feasible or optimal design configuration for sustainable means of power supply for off-grid areas was presented. The result obtained was then assessed based on the various available funding options. In particular, the Public-Private-Community- Oil and Gas Partnership (PPCOP) funding model presents the most feasible solution that delivers the lowest cost of electricity (COE) to the consumer, based on the premise that some of the components of the power supply value chain are donated to the project rather than bought.