Techno-economic Considerations Research Articles

Integrating the Skies for 6G: Techno-Economic Considerations of LEO, HAPS, and UAV Technologies

Integrating the Skies for 6G: Techno-Economic Considerations of LEO, HAPS, and UAV Technologies

Exploring the superior adsorption capacity of multi-layer graphene/alginate granules for the removal of methylene blue dye from water

Graphene-based materials are gaining increasing attention towards their use in manufacturing and environmental applications. In this context, multi-layer graphene (MG) has been recently applied for the adsorption of contaminants from water resulting in promising results. However, the extreme lightness of this material often makes it difficult to handle due to its potential dispersion in the surrounding environment as well as to its transport and loss with the effluent. In this study, a novel granular material was synthesized by embedding MG into an alginate matrix, resulting in the so-called granular MG (GMG). This material was tested for the adsorption of methylene blue (MB) from water, which is a typical dye used in textile industries and must be removed from the effluent. GMG materials with different MG contents (5 and 20 %) were compared with MG and a commercial adsorbent to assess their adsorption capacity and the most performing material was selected for in-depth physical and chemical characterization. The structural, surface, kinetic, isotherm, and thermodynamic properties, the pH and temperature dependence, as well as the regeneration and reuse of GMG 5% were investigated through batch adsorption tests under different operating conditions. The study reveals that GMG 5% has a superior adsorption capacity compared to the tested materials and can be considered as a promising alternative to commercial carbon-based materials according to techno-economic considerations.

Degradation behavior of galvanostatic and galvanodynamic cells for hydrogen production from high temperature electrolysis of water

High temperature electrolysis of water using solid oxide electrochemical cells (SOEC) is a promising technology for hydrogen production with high energy efficiency and may promote decarbonization when coupled with renewable energy sources and excess heat from nuclear reactors. Apart from the technoeconomic considerations, commercial deployment of this technology critically depends on the long-term performance and durability of SOEC cells/stacks, especially under dynamic operations to withstand the intermittency of renewable energy. Herein, SOEC operation was conducted under galvanodynamic conditions and compared with galvanostatic cells to examine the effect on degradation behavior at an average current density of −0.75 A cm−2 at 750 °C. While dynamic operation shows no significant impact on the overall degradation rates compared to constant current operation, minor performance improvement was observed at potentials above 1.5 V when switched to galvanodynamic mode. The relatively lower overpotential during dynamic operation could not be explained by the negligible changes in the electrochemical impedance or cell temperature. Multiphysics modeling reveals that the oxygen partial pressure (PO2) in the electrolyte oscillates with the alternating current density under dynamic operations. The minor improvement in cell performance under dynamic mode might be associated with the relatively lower PO2 buildup as compared with that under galvanostatic operation. In addition, dynamic operation at high frequencies could effectively lower the extreme PO2 in the electrolyte, thus relieving stresses in the cells and alleviating cell degradation.

Performance Evaluation of Grounding Systems of Medium-Voltage Concrete Poles: A Comprehensive Analysis

Designing and installing efficient grounding systems in power distribution networks is considered a complex and crucial task to ensure the reliable operation of power-protective schemes while mitigating hazardous potentials arising from faults, thereby safeguarding both personnel and equipment. This paper aims to offer guidance on designing effective grounding systems in distribution networks by assessing the influence of parameters such as soil structure, fault current magnitude, and fault clearing time. This involves proposing a more precise methodology for calculating hazardous potentials, leveraging software tools like PowerFactory, to accurately determine short-circuit (SC) currents and fault clearing times at specific locations where grounding grids are to be installed. Consequently, Distribution System Operators (DSOs) can design tailored grounding systems that optimize techno-economic considerations without unnecessary over-dimensioning, accounting for the unique characteristics of the Medium-Voltage (MV) Line and soil structure.

Advancing sustainable water treatment strategies: harnessing magnetite-based photocatalysts and techno-economic analysis for enhanced wastewater management in the context of SDGs.

Herein, we explore the holistic integration of magnetite-based photocatalysts and techno-economic analysis (TEA) as a sustainable approach in wastewater treatment aligned with the Sustainable Development Goals (SDGs). While considerable attention has been devoted to photocatalytic dye degradation, the nexus between these processes and techno-economic considerations remains relatively unexplored. The review comprehensively examines the fundamental characteristics of magnetite-based photocatalysts, encompassing synthesis methods, composition, and unique properties. It investigates their efficacy in photocatalytic degradation, addressing homogeneous and heterogeneous aspects while discussing strategies to optimize photodegradation efficiency, including curbing electron-hole recombination and mitigating scavenging effects and interference by ions and humic acid. Moreover, the management aspects of magnetite-based photocatalysts are examined, focusing on their reusability and regeneration post-dye removal, along with the potential for reusing treated wastewater in relevant industrial applications. From a techno-economic perspective, the study evaluates the financial feasibility of deploying magnetite-based photocatalysts in wastewater treatment, correlating reduced pollution and the marketing of treated water with social, economic, and environmental objectives. By advocating the integration of magnetite-based photocatalysts and TEA, this paper contributes insights into scalable and profitable sustainable wastewater treatment practices. It underscores the alignment of these practices with SDGs, emphasizing a comprehensive and holistic approach to managing wastewater in ways that meet environmental, economic, and societal objectives.

Pumps as turbines for pumped hydro energy storage systems - A small-size case study

Pumped Hydro Energy Storage (PHES) technology has been used since early 1890s and is, nowadays, a consolidated and commercially mature technology. PHES systems allow energy to be stored by pumping water from a lower-to a higher-level reservoir. Subsequently, this energy can be released through a turbine placed in a penstock, which connects the two reservoirs, to produce energy. Although these plants have historically been employed at large power scales (in the order of hundreds of MW), in recent years, micro- and small-scale plants are becoming more interesting, due to their possibility of being integrated with renewable energy systems (RES) used in autonomous island grids. Capital costs associated with hydraulic machines used in PHES systems represent the most critical economic factor, which can be mitigated by using commercial centrifugal pumps in reverse mode (Pumps as Turbines, PATs) in place of small hydro turbines. These expected economic benefits must be weighed in each specific case study, with some drawbacks related to the use of PATs, mainly associated to a lower round-trip efficiency with respect to specifically designed pumps and turbines.In this work, a small-scale PHES plant has been studied coupled to an existent photovoltaic system for the integration in the electric grid of a small island in Southern Italy. Two different PHES outlines have been compared based on techno-economic considerations. The former is a typical PHES system composed of both pumps and a turbine, while the latter uses only an array of parallel pumps which work also in reverse mode. The analysis demonstrates the feasibility of integrating a photovoltaic and PHES plant, which results in a lower cost of electricity production, while PHES performance in the PAT-based outline results penalized by the lower efficiency of PATs with respect to the hydraulic turbine.

Does site selection need to be democratized? A case study of grid-tied microgrids in Australia

The choice of suitable sites for microgrids is not only a techno-economic process. Many aspects are important in understanding community support (or lack thereof) for the planning and deployment of grid integration. Alongside usual techno-economic considerations, the site selection process itself must be responsive to the local socio-political context and concerns (e.g., multiple values, needs and expectations of energy infrastructure or perceived fairness of technology deployment). In our project, we developed, in close collaboration with our local partners, an integrated site selection method to address these multiple imperatives. To this end, in addition to socio-technical considerations, our method seeks to (further) democratize network integration technology and its deployment so that it takes into account energy vulnerabilities and inequalities and fully integrates the views of the most affected (especially the most vulnerable) stakeholders into well-informed, place-based deliberative processes. With the support of the method we detail in this paper, we suggest that researchers and practitioners invest time and resources in developing more democratic and place-based site selection methods for microgrids.

(Invited) Bipolar Membrane Electrolysis for CO2 to Ethylene

Carbon dioxide conversion systems are important to drive down the cost of carbon capture through the creation of valuable products. However, how to integrate carbon capture with carbon conversion devices is not yet clear. Bipolar membrane electrolyzers have attracted significant interest as a device which is compatible with carbon capture, as these systems can operate with bicarbonate and carbonate-based solutions. In a bipolar membrane electrolyzer, carbonate is converted to carbon dioxide through a pH swing process driven by water dissociation within the bipolar membrane. However, balancing the rate of water dissociation, carbon dioxide production, and carbon dioxide electrocatalysis remains a critical challenge. Furthermore, steering carbon dioxide electrocatalysis toward a specific high value product such as ethylene is unclear.Here, we set out to examine the activity of Cu, Ag and CuAg catalyst in a carbonate electrolysis system. Cu is a unique metal catalyst and has previously shown the capacity to generate multi-carbon products such as C2H4 and C2H5OH within gas phase anion exchange membrane electrochemical cell. Cu-based catalysts are however known to suffer sluggish C–C coupling kinetics which is a requirement for C2+ product formation. To overcome this challenge, bimetallic are used. For instance, through introducing a known CO-producing catalyst such as Au and Ag with Cu one can perform a cascade reaction. This tandem strategy can enhance performance of multi-carbon products by increasing the coverage of *CO intermediates, known as an important intermediate for C–C coupling, on the Cu surface. Thus, here we will detail a set of experiments aimed at discerning the selectivity of a bipolar-membrane electrode assembly cell which contains Cu, Ag, and Cu-Ag bimetallic electrocatalyst. We examine the impact of temperature, catalyst loading, and system operations. We also will briefly discuss technoeconomic considerations.

Simulation Study of sc-CO2 Based Silylation for Decreasing Severity of Water Blockage and Salt Precipitation during Geological CO2 Storage in Deep Saline Aquifers

Deep saline aquifers are often favorable for underground CO2 sequestration due to their large capacity and relatively low likelihood for resource conflicts. However, many possible issues can arise during CO2 injection. Often these aquifers have a significant salinity level (as these often present minimal resource conflict issues) and as such salt precipitation near the injection wellbore can be problematic. Furthermore, when water blockage occurs, salt precipitation can be exacerbated since large amounts of water remain near the wellbore. Altering the rock wettability towards less water-wet can alleviate water blockage and in turn reduce the likelihood or severity of salt precipitation. Previous lab experiments have shown that supercritical CO2 (sc-CO2)-based silylation can effectively functionalize rock surfaces with hydrophobic silanes. In this study, numerical models were constructed to evaluate the combined effects of multi-phase fluid flow, water evaporation and salt precipitation assuming a change in wettability (thus impacting the relative permeability characteristics of the reservoir) resulting from the silylation process. The aim of this study is to evaluate the efficacy of this chemical treatment to address near wellbore salt precipitation induced by CO2 injection. According to the simulation results, a decrease in injectivity due to salt precipitation is more significant when water blockage is also present. Injectivity is deteriorated prominently in high salinity reservoirs with water blockage since evaporation into the injected CO2 phase will cause significant salt precipitation. In a representative formation, the injectivity decline is worse (up to 68.6% relative injectivity change (RIC)) when both salt precipitation and water blockage are considered since the latter provides more trapped brine inducing more salt accumulation around the wellbore. With hydrophobic silylation, the combined effects of salt precipitation and water blockage on RIC are decreased on an absolute basis by up to 7%. Depending on techno-economic considerations, this method is encouraged to be implemented as early as possible during a CO2 injection program to minimize salt accumulation from the outset.

Planning of an LVAC Distribution System with Centralized PV and Decentralized PV Integration for a Rural Village

Energy demand is continuously increasing, leading to yearly expansions in low-voltage (LV) distribution systems integrated with PVs to deliver electricity to users with techno-economic considerations. This study proposes and compares different topology planning strategies with and without PVs in a rural area of Cambodia over 30 years of planning. Firstly, the optimal radial topology from a distribution transformer to end-users is provided using the shortest path algorithm. Secondly, two different phase balancing concepts (i.e., pole balancing and load balancing) with different phase connection methods (i.e., power losses and energy losses) are proposed and compared to find the optimal topology. Then, the integration of centralized (CePV) and decentralized PV (DePV) into the optimal topology is investigated for three different scenarios, which are zero-injection (MV and LV levels), no sell-back price, and a sell-back price. Next, the minimum sell-back price from CePV and DePV integration is determined. To optimize phase balancing, including the location and size of PV, an optimization technique using a water cycle algorithm (WCA) is applied. Finally, an economic analysis of each scenario based on the highest net present cost (NPC), including capital expenditure (CAPEX) and operational expenditure (OPEX) over the planning period, is evaluated. In addition, technical indicators, such as autonomous time and energy, and environmental indicator, which is quantified by CO2 emissions, are taken into account. Simulation results validate the effectiveness of the proposed method.

Techno-economic assessment of energy storage systems in multi-energy microgrids utilizing decomposition methodology

Renewable resources and energy storage systems integrated into microgrids are crucial in attaining sustainable energy consumption and energy cost savings. This study conducts an in-depth analysis of diverse storage systems within multi-energy microgrids, including natural gas and electricity subsystems, with a comprehensive focus on techno-economic considerations. To achieve this objective, a methodology is developed, comprising an optimization model that facilitates the determination of optimal storage system locations within microgrids. The model considers various factors, such as operating and emission costs of both gas and electricity subsystems, and incorporates a sensitivity analysis to calculate the investment and maintenance costs associated with the storage systems. Due to the incorporation of voltage and current relations in the electricity subsystem as well as gas pressure and flow considerations in the natural gas subsystem, the developed model is classified as a mixed-integer nonlinear programming model. To address the inherent complexity in solving, a decomposition approach based on Outer Approximation/Equality Relaxation/Augmented Penalty is developed. This study offers scientific insights into the costs of energy storage systems, potential operational cost savings, and technical considerations of microgrid operation. The results of the developed decomposition approach demonstrate significant advantages, including reduced solving time and a decreased number of iterations.

Techno-economic considerations on cement substitute obtained from waste refining

Concrete production is the 3rd most intensive source of anthropogenic pollution, mainly due to its high energy and material demand. Previous struggles to decarbonize the concrete sector have identified that some 88% of the environmental burden is associated with cement production. Efforts to substitute some of the cement with char are of increased interest recently as some chars are considered carbon negative which could turn the entire concrete segment into a carbon-sequestering business. Here we transformed biowaste (fermentation residues) via waste heat (from flue gases at biogas plants) into char that was subsequently activated (by reactants made of scrap metal) to capture phosphorus (at wastewater treatment plant) into phosphates and thus produced novel a cement substitute. Changes in the strength characteristics of the concrete were analyzed and optimized based on robust semi-operational testing. The molecular dynamics simulations performed elucidate the mechanisms by which activation of char (FeCl3 and CaCl2) interacts with phosphorus at wastewater treatment plants (H2PO4−) and generates phosphate-enriched char as a source of crystallization nuclei in concrete.

Powering battery sustainability: a review of the recent progress and evolving challenges in recycling lithium-ion batteries

As the global consumption of lithium-ion batteries (LIBs) continues to accelerate, the need to advance LIB recycling technologies and create a more robust recycling infrastructure has become an important consideration to improve LIB sustainability and recover critical materials to reuse in new LIB production. Battery collection, sorting, diagnostics, and second-life usage all contribute to the LIB logistics network, and developments in each of these areas can improve the ultimate recycling and recovery rate. Recent progress in LIB recycling technology seeks to increase the amount of valuable metal compounds, electrode materials, and other LIB components that are recoverable and that can be redeployed in new LIB production or other markets. This review establishes an overview of these developments and discusses the strengths and weaknesses of each major recycling technology. Of particular note are the differences in recycling technology and infrastructure requirements created by various LIB markets, as well as the techno-economic considerations for different recycling methods based on the evolving LIB formats and component compositions.

Improving the Criteria for Transmission Line Routing beyond the Techno-Economics: The Case of Afghanistan

It is not always the technical, financial, and environmental aspects of power projects that decisions are based on. There are many other political, social, and local issues shaping the decision-making processes. This research shows how political and social issues challenged the decision-making process of a high-voltage transmission line routing and how to avoid such unwanted consequences in similar projects. Our insights reveal the importance of risk, conflict, and stakeholder management techniques and strategies in successfully delivering power projects. When planning large energy projects, it is of utmost importance to engage and consult stakeholders, especially direct recipients, civil society, political parties, people’s representatives, and experts, in addition to the techno-economic considerations. Finally, it is suggested that there should be an authority at the country level responsible for deciding on routing, siting, prioritizing, and the strategic planning of power projects.

The potential for hydrogen ironmaking in New Zealand

Globally, iron and steel production is responsible for approximately 6.3% of global man-made carbon dioxide emissions, because coal is used as both the combustion fuel and chemical reductant. Hydrogen reduction of iron ore offers a potential alternative ‘near-zero-CO2’ route, if renewable electrical power is used for both hydrogen electrolysis and reactor heating. This paper discusses key technoeconomic considerations for establishing a hydrogen direct reduced iron (H2-DRI) plant in New Zealand. The location and availability of firm renewable electricity generation is described, the experimental feasibility of reducing locally-sourced titanomagnetite ironsand in hydrogen is shown, and a high-level process flow diagram for a counter-flow electrically heated H2-DRI process is developed. The minimum hydrogen composition of the reactor off-gas is 46%, necessitating the inclusion of a hydrogen recycle loop to maximise chemical utilisation of hydrogen and minimize costs. A total electrical energy requirement of 3.24 MWh per tonne of H2-DRI is obtained for the base-case process considered here. Overall, a maximum input electricity cost of no more than US$80 per MWh at the plant is required to be cost-competitive with existing carbothermic DRI processes. Production cost savings could be achieved through realistic future improvements in electrolyser efficiency (∼ US$5 per tonne of H2-DRI) and heat exchanger (∼US$3 per tonne). We conclude that commercial H2-DRI production in New Zealand is entirely feasible, but will ultimately depend upon the price paid for firm electrical power at the plant.

A comprehensive optimal energy control in interconnected microgrids through multiport converter under N−1 criterion and demand response program

Nowadays, the local distribution grids have been facing technical, economic, and regulatory challenges, because of the increased integration of renewable energy sources (RESs) and electrification of vehicles. The traditional solutions to the grid expansion, e.g., to build an additional power line, are utility-centered solutions, i.e., the distribution grid operators (DSOs) are the only party involved to tackle grid issues. The DSOs have to engage grid users with technology providers to develop innovative solutions that tackle one problem and overcome several cost-effectively. This paper presents a holistic solution to optimally control cross-sectoral energy flow between interconnected microgrids (MGs) consisting of different RESs, hydroelectric power plant (HPP) and wind turbines (WTs) to meet electric vehicles (EVs), residential, commercial and industrial demands with the main grid contribution. This issue will provide the advantages of community-based MGs for local energy trading which causes for an active and engaged system, however, an adequate control strategy for proper operation is required. The proposed solution is based on a new interconnection line between two MGs through a multiport converter (MPC) with the techno-economic consideration of newly installed components such as MPC, cables and the required battery energy storage system (BESS). The proposed case study is evaluated under three different conditions e.g., load increment, demand response (DR) and N-1 criterion in separate, interconnect and island modes. The CPLEX solver of GAMS software is employed to solve the mixed-integer linear programming model. The results show that the applied interconnection line for MGs compared to the separated operation mode can decrease the system's total costs, reduce the applied peak to the upstream grid, and enhance the system's reliability under different conditions. Furthermore, the applied solution provides the ability for MGs operation even in island mode under different conditions for a full day (24 h).

Removal of nutrients and other emerging inorganic contaminants from water and wastewater by electrocoagulation process

The continual discharge of emerging inorganic pollutants into natural aquatic systems and their negative effects on the environment have motivated the researchers to explore and develop clean and efficient water treatment strategies. Electrocoagulation (EC) is a rapid and promising pollutant removal approach that does not require any chemical additives or complicated process management. Therefore, inorganic pollutant treatment via the EC process is considered one of the most feasible processes. The potential developments of EC process may make the process a wise choice for water treatment in the future. Thus, the present study mainly focuses on the use of EC technology to remove nutrients and other emerging inorganic pollutants from water medium. The operating factors that influence EC process efficiency are explained. The major advancement of the EC technique as well as field-implemented units are also discussed. Overall, this study mainly focuses on emerging issues, present advancements, and techno-economic considerations in EC process.

Optimization of a Hybrid Energy System with District Heating and Cooling Considering Off-Design Characteristics of Components, an Effort on Optimal Compressed Air Energy Storage Integration

In this work, the optimal design of a hybrid energy complex, including wind turbines, an internal combustion engine, and an adiabatic compressed air energy storage system is investigated. A novel bi-level optimization strategy is proposed for optimizing the capacity and operational power of each component of the system based on techno-economic considerations. The article presents information and discussions about the impacts of the partial-load operation of the energy storage system components on the optimal rated power and working strategies. The off-design characteristics are proven to have a huge negative impact on the efficiency and economy of the hybrid system. The efficiency reduction of the compressed air energy storage system is about 21% in summer and 8.9% in winter, when the system is operating in partial-load conditions. The operation cost of the system is reduced significantly when carrying out the proposed bi-level optimization strategy.

Pathways of lignocellulosic biomass deconstruction for biofuel and value-added products production

As the world attempts to transition from fossil fuels, lignocellulosic biomass (LCB) serves as a promising alternative due to its high abundance. Hydrolysing LCB can generate various bioproducts, such as biofuels and value-added chemicals. However, the presence of lignin inhibits the solubilization of LCBs, presenting a major techno-economic challenge in the biorefinery concept. Therefore, this paper addresses the gaps left by most of the recent review works that fail to comprehensively review different pretreatment methods and the full scope of applications of LCBs, and do not incorporate techno-economic considerations of the technologies, the latter being the greatest bottleneck in the commercialization of the processes. The literature review revealed that while many of the physical and chemical pretreatment methods exhibit great effectiveness, they have a huge dependence on energy, chemicals, water, and/or specialized equipment, and produce harmful waste and inhibitory compounds. The pretreatment of lignocellulosic biomass can account for 40% of total production costs. Biological pretreatment can address these challenges but is limited by long incubation times. For instance, the bacterial pretreatment can noticeably reduce sawdust cellulose, hemicelluloses, and lignin contents by 35.8%, 37.1%, and 46.2%, respectively. Recently, integrated/coupling (hybrid) methods, such as chemical-assisted liquid hot water/steam and microwave or ultrasound-assisted alkaline pretreatment, have been gaining popularity due to their potential to improve chemical yield, but at the expense of the high cost of operation. To make pretreatment processes more techno-economically feasible, there is a need for process integration and the standardization and optimization of process parameters.

Preliminary Techno-Economic Considerations of the Sisal Process - Closing Materials Loops through Industrial Symbiosis

Preliminary Techno-Economic Considerations of the Sisal Process - Closing Materials Loops through Industrial Symbiosis