Electricity Generation Research Articles

Tri-generation of sensible heat, hydrogen, and electricity in an aluminum-air flow battery (AAB) system

The performance of an aluminum-air flow battery (AAB) unit cell is experimentally studied for application to a tri-generation system as a district heating resource of sensible heat storage, hydrogen production, and electric power generation. A layer-type unit cell is designed to protect against leakage of hydrogen gas during operation and to ensure electrolyte circulation in the AAB system. The electrolyte is made with NaOH pellets dissolved in purified water. A direct current (DC) loader is used to measure the electric power of the AAB unit cell, while a resistance temperature detector (RTD) is used to measure the electrolyte temperature at the unit cell inlet and outlet. The objective of the present work is to study the effect of operation parameters [i.e., electrolyte temperature (Tin), mass flow rate (ṁNaOH), and molar concentration (XNaOH)] on the performance of the tri-generation AAB system. The electric power of the AAB unit cell increases in the electrolyte temperature from 20 ℃ to 50 ℃ with increases in the NaOH molar concentration from 1 M to 4 M. The performance measurement of the AAB unit cell shows that the total surface power density of sensible heat, hydrogen, and electric power increased with increases in electrolyte temperature from 35 ℃ to 55 ℃. The tri-generation system operates for 140 min under the condition of Tin = 40 ℃, ṁNaOH=14.48 g/s, and XNaOH=4 M.

Performance Analysis of a Self-Decarbonizing Combustor

Abstract Hydrogen is envisioned to be a key decarbonization solution for fossil fuel-dependent power generation and aviation industries. At present, a significant fraction of the generated electrical power is derived from natural gas. As such, the external energy needed for hydrogen generation, often sourced from fossil fuels, results in CO2 emissions, compromising overall carbon neutrality. Instead, the processes of hydrogen generation can be energetically coupled with the combustion process, in situ, to eliminate external energy requirements. To that end, a novel self-decarbonizing combustor (SDC) has been conceptualized, integrating methane pyrolysis with the combustion process that can in principle decarbonize many contemporary power generation technologies. The underpinning methane pyrolysis process enables in situ pre-combustion capture of solid carbon, while simultaneously generating hydrogen. Consequently, CO2 emissions resulting from the combustion of processed, hydrogen-enriched fuel are mitigated. This study provides a comprehensive analysis, delineating the operating principle and the effect of some of the important governing parameters on the performance of the self-decarbonizing combustor. These parameters, including fuel temperature, residence time, pressure, and catalysis, are studied in the context of potentially applying the proposed concept to natural gas-based decarbonized electrical power generation. Investigating fuel chemistry, combustion exhaust, and carbon structure and morphology under varying process parameters enhances our comprehension of the SDC. Additionally, its self-sufficient nature eliminates the need for separate hydrogen production, storage, and transportation infrastructure, highlighting its potential as a scalable and realizable technology.

Simultaneous costs minimizing in electricity and gas micro-grids with the presence of distributed generation

Distributed generation can actively participate in the day-ahead markets, real-time power balance, and wholesale gas markets to achieve various goals, such as supplying gas to various electric power generation plants. A multi-objective network with two types of loads is considered in this paper. The reason for the simultaneous optimization of these two networks is that these two energy carriers are dependent on each other and gas is needed to produce electricity, so this issue can be addressed with a multi-objective function. The simulation carried out in this article is coded in GAMS software as a mixed integer linear programming (MILP). The efficiency of gas turbines and fuel cells in this article is dependent on their working point, and considering the exact model of these resources and the relationships related to the calculation of their fuel consumption is non-linear. On the other hand, a binary variable has been used to show the charging and discharging state of the storage and the on-and-off state of the gas turbines. Therefore, the problem considered in this article is a MILP problem. The results of this article are the proper planning of charging and discharging of the energy storage system with the proper planning of the power generation of different energy sources considering the network loads in two optimized and non-optimized scenarios.

Review of best practices for global cogeneration policy: Benchmarking and recommendations for Malaysia

Despite the Malaysian government's efforts to promote cogeneration technology, it constitutes a mere 4.2 % of the country's total electricity generation. To address this issue, this review article aims to identify and benchmark global best practices for bolstering cogeneration implementation in Malaysia. While previous studies in this domain have centered on examining government policies within the specific regions, this paper underscores the imperative for an updated and comprehensive literature review to systematically collect and categorise best practices from around the world. This work examines the adoption of cogeneration energy systems within nations characterised by a substantial presence in their energy composition, simultaneously exploring the roles of regulatory frameworks in promoting their uptake. The scope of the literature review includes statistical data, reports, and other relevant scholarly works on cogeneration policies. Based on the findings, the review paper concludes that well-crafted policies are instrumental in encouraging rapid technology advocacy. The legislative landscape pertaining to cogeneration implementation in Malaysia is scrutinised, followed by a comparative analysis against global best practices to identify opportunities for improvement. Three crucial elements emerge as paramount to expediting the adoption: (i) administrative recognition, (ii) financial initiatives, and (iii) regulatory improvements. Several recommendations for the Malaysian cogeneration roadmap are presented. Overall, this paper offers insights into the chronological evolution of cogeneration policy development and provides actionable guidelines for developing effective policies in Malaysia and other South-East Asian countries.

N/NiO-ornated graphitic fiber-engrained micro-carbon beads: Innovative packed bed type capacitive electrodes for microbial fuel cells

Nitrogen-doped nickel oxide-catalyzed carbon nanofiber-decorated micro-activated carbon beads (NiO-N-CNF/ACB) were synthesized through suspension polymerization and employed as capacitive fixed-packed bed electrodes in microbial fuel cell (MFC-) for wastewater treatment and byproduct electricity generation. The capacitive electrode was meticulously designed to manifest enhanced characteristics crucial for MFC applications. The large specific surface area of NiO-N-CNF/ACB offers advantages in terms of catalytic sites and stored charge produced by electrogenic bacteria to form an electrochemical double-layer on the electrode, thereby enhancing power generation. The incorporation of NiO, coupled with graphitic contents, biocompatibility, and the formation of three-dimensional structures, contributes to the excellent performance of the NiO-N-CNF/ACB electrodes. The NiO-N-CNF/ACB electrodes-based MFC operated in batch mode demonstrated an open-circuit potential of 0.8 V, an impressive maximum power density of 2900 mW/m3, and a noteworthy 74 % reduction in chemical oxygen demand. Additionally, the synthesized NiO-N-CNF/ACB exhibited a remarkable specific capacitance 754 F/g and a cumulative total charge of 255 C/g, surpassing the corresponding values for plain NiO-ACB and ACB. This study positions NiO-N-CNF/ACB as a promising capacitive packed bed electrode material, offering enhanced power generation, efficient wastewater treatment, and superior biofilm formation, thereby advancing the potential for sustainable and efficient MFC systems.

Study on the Water Use at the Tailwater of Nam Theun 2 Hydropower Station through the Canal of the 3rd Water Gate (Case study: Nongping and Boungbao villages) Nhommalath District, Khammounce Province

Water management is managed through the Nam Theun 2 hydroelectric project. The project has released water in two parts: 1) Water gates and channels release water into natural streams about 30 km long and can drain 1,200 m3/s; and 2) Releasing through the newly constructed regulating dam to the Xe Bang Fai River directly, with a length of about 27 km, can drain 330 m3/s. According to the length of the channel, there is a built water gate for 5 irrigations. Currently, only 3 water gates have been opened to supply water for production in 9 villages that depend on Nhommalath district, Khammouane province. In order to make the use of water through the channel to the maximum benefit, it can operate together between electricity generation and the actual use of water by the community. In this chapter, we have studied the amount of water flow according to the season through Regulating Dam during the past 11 years. Since 2012 to 2022, we have studied the participation of farmers in the management and use of water within the scope of agricultural land. Through comparing the amount of water flow during the past 11 years, from 2012 to 2022, The amount of water flow through the channel with the lowest flow in December 2022 is equal to 0.0 cubic meters per second caused by the stoppage of the company's electricity production to do various repairs, and the highest flow rate in November 2016 was 318.18 cubic meters per second. The reason is that the project has full production capacity to respond to the electricity buyers. Among them, the annual average flow volume with the lowest value in 2022 is equal to 153.06 cubic meters per second, and the annual average flow volume with the highest value in 2017 is equal to 239.11 cubic meters per second. At the time the company stopped production, it used a backup pump with a suction power equal to 0.083 m3/s, which was installed at 2 points to pump water into the irrigation channel for the people. The company is responsible for all costs, such as fuel for the pump, maintenance of the pump, and the water system from the pump to the channel. Assessment of farmers' participation in water management with topics such as survey participation and data collection, participation in the implementation of four seasonal plans, participation in monitoring and evaluation, and participation in the review of all outputs is at a very satisfactory level ( = 3-3.8), except for the topic of participation in determining water use regulations within the channel, and the flood problems are evaluated at a moderate level ( = 2.4). Because of management, the municipality has appointed a committee and has specific management rules. There has never been a natural disaster in the area in the past, such as a drought or flood.

FLOW AND HEAT TRANSFER IN A RIBBED CONVERGING-DIVERGING U-DUCT UNDER ROTATING AND NON-ROTATING CONDITIONS

Abstract A numerical study based on steady RANS with the SST turbulence model was performed to investigate the flow and heat transfer in a ribbed U-duct with a rectangular cross section that converges linearly in the radially outward direction and diverges linearly in the radially inward direction under rotating and non-rotating conditions. Parameters examined include rotation number (Roi = 0, 0.0219, 0.0336, 0.0731), Reynolds number (Rei = 46,000, 100,000, and 154,000), and the duct's taper angle (α = 0° and 1.41°) under conditions relevant to gas turbines used for electric power generation. Results obtained show that increasing the taper angle from 0° to 1.41°, which appears negligibly small, significantly increases both the friction coefficient and the Nusselt number whether there is rotation or not. With rotation at Roi = 0.0336 and Rei = 100,000, the maximum increase in the average friction coefficient and Nusselt number was found to be 41.7% and 36.6% respectively. Without rotation at Rei = 46,000, those are 11.5% and 14.7% respectively.

Total electricity generation dynamics analysis and renewable energy impacts in South Africa

AbstractThis research explores the dynamics of total electricity generation (TEG) in South Africa through an analysis of data from the International Energy Agency database from 1990 to 2020. A comprehensive examination of various energy sources, including coal, oil, biofuels, nuclear, hydro, solar photovoltaic (PV), solar thermal, and wind, is conducted to ascertain their respective contributions to TEG. Employing the R software environment, the study employs a methodical analytical framework encompassing meticulous data preparation, statistical analysis, and model formulation. The data preparation phase involves intricate processes such as structuring, cleansing, and visualization aimed at eliminating stochastic variables and outliers. Missing data are addressed through the application of the Piecewise Cubic Hermite Interpolating Polynomial method. Subsequent statistical analyses are informed by tests for normality and homogeneity of variance, revealing deviations from normality and disparate variances across energy source groups. Consequently, non‐parametric methodologies such as the Kruskal–Wallis test are adopted. Findings underscore the significant role of nuclear energy in TEG despite facing challenges. Model development entails the construction of multiple linear regression models with varying predictor sizes, with Model m06 emerging as the optimal choice, incorporating key predictors such as coal, nuclear, and solar PV. Rigorous diagnostic assessments confirm the robustness of Model m06 and its suitability for TEG prediction. Comparative analysis against actual data validates its superior performance, characterized by minimal errors and high predictive accuracy. The efficacy of Model m06 in capturing TEG dynamics underscores its utility for informing energy planning initiatives. Recommendations derived from the study advocate for prioritizing renewable energy integration, infrastructure investment, research endeavors, monitoring mechanisms, and public awareness campaigns to advance sustainable energy development goals in South Africa.

Multi-criteria decision-based hybrid energy selection system using CRITIC weighted CODAS approach

A complex and multicriteria decision making (MCDM) problem arises in a bid to select the most appropriate hybrid energy system among several combinations in distributed electricity generation as it involves conflicting criteria that must be simultaneously considered. In this work, Criteria Importance Through Intercriteria Correlation (CRITIC) along with Combinative Distance-Based Assessment (CODAS) was employed to select a suitable hybrid energy system combination for water pumping from four conflicting alternatives of Biomass-Battery (S1), PV-Battery (S2), PV-Biomass (S3), and PV-Biomass-Battery (S4) by objective weight estimation. This was followed by a confirmation by the Additive Ratio Assessment (ARAS) method for the solution. The results presented show that CRITIC method reveals 0.275, 0.224, 0.248, and 0.252 as different weights of the four alternatives of S1, S2, S3, and S4, respectively. The ranking results reveal S4 as the best alternative based on an assessment score of 0.4693. The same hybrid system was confirmed by ARAS based on overall performance and degree of utility of 0.287697 and 0.823716, respectively.

3D printing of phase change material-based Pickering emulsion gel for solar-thermal-electric conversion

The rapid global increase in the consumption of fossil energy had led to urgent environmental issues, thereby prompting vigorous efforts towards the development and application of renewable energy. The effective encapsulation of phase change materials (PCMs) is crucial and indispensable for achieving high-performance solar-thermal energy harvesting and storage. However, challenges persist in the manufacturing of PCMs encapsulations with customizable and intricate structures to meet diverse scenarios. Herein, a PCMs Pickering emulsion gel ink, based on lignocellulosic nanofibers (LCNFs)/graphene oxide (GO) nanosheets stabilized paraffin, has been prepared to fabricate customized PCMs using 3D printing techniques for solar-thermal-electric conversion applications. The micro-nano matrix consisting of LCNFs and GO nanosheets provides a stable oil/water (O/W) interface, limits movements and deformability of paraffin microsphere, thereby increasing the viscosity and stiffness of the PCMs Pickering emulsion gel ink to ensure its excellent rheological property. Moreover, the LCNFs enhance printability and shape fidelity of the ink as interfacial stabilizer and viscosity modifier, which facilitates the manufacture of various 3D geometries. As a result, the designed concave PCMs solar harvester not only exhibits exceptional solar-to-thermal conversion efficiency, but also effectively mitigates heat loss and enables efficient heat storage for electricity generation. Our work demonstrates a new way toward utilization of LCNFs as PCMs emulsion stabilizers and encapsulants in PCMs and the fabrication customized PCMs architectures for solar-thermal-electric conversion applications using 3D printing techniques.

Rooftop PV Potential Determined by Backward Ray Tracing: A Case Study for the German Regions of Berlin, Cologne, and Hanover

ABSTRACTPhotovoltaics (PV) on building rooftops is a major contributor to the decarbonization of energy systems. We simulate the PV energy yield potential for 2.5 million individual roofs in three German regions. We cumulate the results for each single roof to calculate the cost‐potential curves for the three cities Berlin, Cologne, and Hanover. These curves give the amount of electricity that can be generated at less than a given cost per kWh. We find that these curves have the shape of a hockey stick. Neglecting the dependence of PV investment on building size and thus on the system sizes causes largely different cost‐potential curves that differ by 11%–18% for flat roofs due to their heterogeneous building size distribution. The cost‐potential curves of the three cities are very similar when appropriately normalized, for example, by the local solar irradiation and the settlement area of the city, despite substantial variations in population density. This allows for an extrapolation of our results. For Germany, we reveal an upper limit for the total electricity generation from rooftop PV of 762 TWh/a with cost as low as 6.9 ct/kWh without accounting for area losses due to chimneys, air conditioning systems, and so forth. We estimate the actual potential to be at least half of that figure.

Assessment of the causal links between energy, technologies, and economic growth in China: An application of wavelet coherence and hybrid quantile causality approaches

It is undeniable that energy and technology play a vital role in driving the economic growth of a country. This paper's objective is to check the unexplored causal links between electricity generation and GDP growth in China by using a multivariate framework that contains technologies in the production or processing of goods, gross capital formation, labour force, financial sector development, and primary energy consumption as supplementary factors in growth model using the updated data. Applying new advances in time series data analysis, the study used wavelet coherence and hybrid non-parametric quantile causality approaches to analyze whether these factors predict GDP growth. We observed that technologies, capital formation, labor force, energy consumption, financial sector development, and electricity generation propel GDP growth in China. The quantile causality in mean and variance also corroborates that all these factors are causatives of GDP growth across their entire distribution. The Breitung-Candelon Spectral Granger-causality method further sustains the robustness of these results. Our findings provide valuable insight to policymakers to pave the way for these causative factors, mainly promoting electricity projects and adapting new technologies to propel economic growth in China.

Enhancing electricity generation from water evaporation through cellulose-based multiscale fibers network

Harvesting energy from the water − solid interface through natural water evaporation provides a promising approach for generating sustainable electricity to power self-powered electronics. Advancing the bio-based hydrovoltaic materials enhances sustainability, with wood as a viable candidate due to the inherent hydrophilic and charged properties. However, current wood-based water evaporation-induced electricity generators (WEIGs) mainly depend on the “top-down” construction strategies. Wherein, the improvement of power density is constrained by the limited structural regulation, nondiverse building blocks, and monolithic enhancement mechanisms. Here, the high-performance wood-based WEIGs based on multiscale fibers network (MFN) are reported by embedding the Ti4O7 nanofibers (T4NF) inside the assemblies of TEMPO-oxidized cellulose nanofibrils (TOCNF) through a “bottom-up” route. Benefiting from the large specific surface area, high surface potential, and photothermal effect of conductive T4NF, the WEIG achieves a high short-circuit current of ∼13.7 μA while delivering ∼0.94 V open-circuit voltage. This work presents an efficient method to boost performance while understanding the impact of functional MFN on water evaporation.

Technologies of the Integrated Development of Hydrogeothermal Resources of the North Caucasian Region

This paper focuses on the technologies of the integrated development of high-parametric geothermal brines with steam release. They differ from each other depending on initial parameters. Such way of brine utilization will make it possible to transform thermal energy to electrical power along with significant increasing its salinity that contributes to chemical components extraction. The opportunity is considered of this technology application in the Tarumovka geothermal field with electric power generation in steam-turbine and binary power plants, and consequent obtaining valuable mineral components. The geothermal and biogas technologies are given proposing integrated utilization of thermal water for various applications. Such systems make it possible to use resource potential of geothermal well and biomass that will result in improvement of economic and environmental situation in the North Caucasus region.

Hydrovoltaic electricity generation induced by living leaf transpiration

Hydrovoltaic electricity generation induced by living leaf transpiration

Environmental, technological, and economic analysis of supercritical coal-fired power system.

Developing countries primarily rely on fossil-based energy sources to meet their energy demands. The use of fossil fuels has several adverse environmental repercussions that damage the biosphere both directly and indirectly. Among fossil fuels, coal brings about the heaviest environmental externalities, yet its abundance makes its use widespread, particular in countries having significant power generation deficits, such as Pakistan. This study presents an environmental, technological, and economic analysis of a supercritical coal-based power unit located in Pakistan and used for electricity generation. For environmental assessment, the CML-1A baseline method in OpenLCA software was used, and eight midpoint impact indicators were selected. The functional unit chosen was 1 MWh of generated electricity. The results indicated that the category of ozone layer depletion has the least impact, whereas global warming potential has the highest impact score. Except for photochemical oxidation and human toxicity, the plant operational stage dominated most of the selected impact categories. The current paper also reveals that the removal efficiency of CO2 and other pollutants is higher in supercritical compared to subcritical plants. Moreover, the economic feasibility of supercritical plant is compared with chemical looping combustion (CLC)-based supercritical coal-fired power plant, and results shows that CLC-based coal-fired power plant is a more competitive and environmentally friendly option. The utilization of a scientific cleaner energy-management system in real-time, as exemplified in this study, may facilitate the development of a optimalpolicy framework that encouragesfor the adoption of cleaner coal power generation in developing countries, ultimately resulting in improved energy sustainability. Furthermore, this paper also presents some policy implications which could be helpful for policymakers, researchers, and industrialists to improve the sustainability of energy in emerging economies.

The Effect of Gas Turbine Inlet Air Temperature On Electricity Production Effiency in Trigeneration Power Plants

In this study, the operation of gas turbines used to generate energy in trigeneration plants with turbine inlet air at various temperatures was investigated. In today's world, the importance of energy and its efficient use is increasing. Developing population and technologies have increased the energy we need, and thus energy costs have reached serious levels. All these reveal the necessity of using energy efficiently. Trigeneration power plants provide less fossil fuel consumption than conventional production because they have high efficiency, prevent line losses with on-site electricity generation, and provide combined energy production. In our study, the increase in electricity production efficiency by cooling the inlet air of the Solar Turbines Taurus 60 gas turbine used in the trigeneration power plant was examined. It was determined that there was a 30.08% increase in active power efficiency in electricity production by cooling the turbine inlet air from 41.2 °C to 9.1 °C.

Development of a Smart Metering System for Efficient Energy Consumption

Smart energy concepts are based on the utilization of emerging integrated microprocessors and communication technologies for monitoring energy consumption. In the utilization of electricity, energy management is a core problem, especially for cost savings to the benefit of electricity customers. In modern electricity generation, transmission and consumption, energy management has occupied the center of attention for sustainable techno-economic motives. The present-day power sector has an immense role to play in the overall economic performance of the global community, thus, requiring the application of efficient and reliable metering systems for the measurement of energy consumption. The application of a smart metering system depends on the effectiveness of the embedded smart communication interface in the utility service provider system and the energy consumers’ metering devices based on energy supply reliability and consumption security. Therefore, this study focuses on the design and development of an efficient smart energy meter using the advancements provided by the Internet of Things (IoTs). The system was tested based on the collection of real-time data and subsequently analyzed for performance evaluation through a case study of household data collection.

Hydrogen Infrastructure in the Future CO2‐Neutral European Energy System—How Does the Demand for Hydrogen Affect the Need for Infrastructure?

The fast rollout of hydrogen generation, transport, and storage infrastructure has become a top priority of the European Union and its member states. Planning hydrogen infrastructure requires a thorough understanding of the future role of hydrogen in the energy system. At the same time, there is still huge uncertainty about the future demand for hydrogen and its overall role. An energy systems analysis is conducted with high temporal and spatial as well as technological resolution under alternative demand scenarios. An energy system model is used to optimize the entire European energy system with hourly time resolution and high spatial consideration of renewable energy potentials. The hydrogen demand in the five scenarios ranges from about 700 TWh for mainly industrial uses to 2800 TWh in all sectors in the EU27 + UK by 2050. The results show that an integrated European hydrogen system is a robust element of the cost‐optimal system design in all scenarios. This encompasses flexible electrolyzers at the most favorable wind and solar locations, long‐distance hydrogen transport network, large‐scale seasonal underground storage, and electricity generation for peak demand periods. Conclusions about the individual components are provided and high‐resolution data on hydrogen demand are available for future research.

Electricity Generation at Gas Distribution Stations from Gas Surplus Pressure Energy

At gas distribution stations (GDSs), the process of throttling (pressure reduction) of natural gas occurs on gas pressure regulators without generating useful energy. If the gas expansion process is created in a turbine, to the shaft where an electric generator is connected, then electricity can be obtained. At the same time, the recycling of secondary energy resources is provided, which is an important component in the efficient use of natural resources. The obtained electric power can be supplied to the external power grid and/or used for the GDS’s own needs. The process of generating electricity at the GDS from gas overpressure energy is an environmentally friendly, energy-saving technology that ensures an uninterrupted, autonomous operation of the GDS in the absence of an external energy supply. The power needs of a GDS with regard to electricity are relatively small (5 ÷ 20 kW). Expansion in throttling devices or turbine flow paths leads to gas cooling with a possible hydrate formation. It is prevented via gas preheating or vortex expansion equipment that keeps the further gas temperature at a necessary level. Turbogenerators can be created on the basis of vortex expansion turbomachines, which have many advantages compared to turbomachines of other types. This article studies how gas pressure (outlet: gas distribution station) and gas preheating (inlet: vortex expansion machine) influence turbogenerator parameters. Nine turbogenerator variants for the power needs of gas distribution stations have been assessed.