Technical-economic Analysis Research Articles

Technical–Economic Analyses of Electric Energy Generation by Biogas from Anaerobic Digestion of Sewage Sludge from an Aerobic Reactor with the Addition of Charcoal

This study aimed to obtain the energy recovery potential of the biogas produced from anaerobic digestion (AD) of the sludge from a wastewater treatment plant (WWTP), including the use of biochar as an additive for substrate co-digestion and catalyst for methane production. We carried out the following steps: chemical–physical laboratory analyses of sludge samples; the building, operation, and monitoring of an experimental prototype of a batch bioreactor of 2.5 L for the AD of the sludge (with and without the addition of charcoal); qualitative measurements of biogas; the study of charcoal morphology; and the projection of useful energy generation from the AD sludge after treatment. A study on the economic viability and avoided greenhouse gas (GHG) emissions was performed based on the experimental results. The substrate showed alterations in all the physicochemical parameters evaluated after AD, such as a reduction of 35% in the biochemical oxygen demand (BOD) analysis; the experiment carried out using biochar showed positive results regarding the speed of CH4 production and a greater potential for energy recovery. Enterprises from 2000 kW onwards would present an internal rate of return (IRR) equal to or higher than the minimum attractiveness rate (MAR) of 15%. The USD 95.28/MWh tariff presented economic feasibility for the studied scenarios. WWTPs that produce enough sludge to generate power of 2000 kW would need to process the waste of 117,200 inhabitants with charcoal addition and 136,000 without charcoal. It would be possible to avoid the emission of 2307.97 tCO2/year (2000 kW). According to the results obtained, this study revealed that using alternative energies based on anaerobic digestion and biochar can generate positive results regarding methane production, and its application as an energy source in a WWTP proved to be economically viable at a specific level of power production.

Study and simulation of the coordination of electrical protections

In this work, an analysis of the coordination of protections of an electrical system is carried out. To do this, the ETAP software is used, which allows the modeling of each element from the single-line diagram of the electrical system. The initial conditions associated with the load level of the elements and lines due to the presence of loads at nominal values are defined. Next, a failure analysis is developed, to carry out a protection coordination study later, defining failure scenarios in different bars of the system, as well as the performance characteristics of the protections. Finally, a technical-economic analysis is carried out, considering historical data on energy consumption by the industrial plant.

Current approaches to meaningful learning that complement the construction of knowledge in the process of reading comprehension

In this work, an analysis of the coordination of protections of an electrical system is carried out. To do this, the ETAP software is used, which allows the modeling of each element from the single-line diagram of the electrical system. The initial conditions associated with the load level of the elements and lines due to the presence of loads at nominal values are defined. Next, a failure analysis is developed, to carry out a protection coordination study later, defining failure scenarios in different bars of the system, as well as the performance characteristics of the protections. Finally, a technical-economic analysis is carried out, considering historical data on energy consumption by the industrial plant.

Feasibility Study of a Wind-Diesel Hybrid System in a Remote Site on Southern of Algeria

In this study, we present an autonomous solution for a village located north of Timimoun in Algeria, with around thirty households. As the region has good wind potential with an average annual speed of around 5m/s, this resource is used to develop a hybrid wind/diesel/battery system. A technical-economic analysis is carried out using the HOMER optimization tool to determine the optimal solution. We considered a range of load sizes, from 0.9 kWh/d to 3.6 kWh/day, and a range of wind speeds, from 3.99 m/s to 5.42 m/s at 10 m from the ground. Several wind turbines with powers ranging from 1 kW to 10 kW have been tested.The best combination is given by the wind/diesel/battery system operating with the WES 5 Tulipo turbine with a rated power of 2.6 kW, with a diesel price equal to 0.22 $/kWh. This solution reduces the COE to 0.569 $/kWh and renewable fraction is maximum (86%). In addition, the emissions of CO2, CO and SO2 decrease to less than 70% of the emissions of Diesel power system. The sensitivity study shows that the wind/diesel/battery system is optimal for any wind speed greater than 3.5 m/s whatever the price of diesel.

Technical–Economic Analysis of Renewable Hydrogen Production from Solar Photovoltaic and Hydro Synergy in a Pilot Plant in Brazil

Renewable hydrogen obtained from renewable energy sources, especially when produced through water electrolysis, is gaining attention as a promising energy vector to deal with the challenges of climate change and the intermittent nature of renewable energy sources. In this context, this work analyzes a pilot plant that uses this technology, installed in the Itumbiara Hydropower Plant located between the states of Goiás and Minas Gerais, Brazil, from technical and economic perspectives. The plant utilizes an alkaline electrolyzer synergistically powered by solar photovoltaic and hydro sources. Cost data for 2019, when the equipment was purchased, and 2020–2023, when the plant began continuous operation, are considered. The economic analysis includes annualized capital, maintenance, and variable costs, which determines the levelized cost of hydrogen (LCOH). The results obtained for the pilot plant’s LCOH were USD 13.00 per kilogram of H2, with an efficiency loss of 2.65% for the two-year period. Sensitivity analysis identified the capacity factor (CF) as the main determinant of the LCOH. Even though the analysis specifically applies to the Itumbiara Hydropower Plant, the CF can be extrapolated to larger plants as it directly influences hydrogen production regardless of plant size or capacity.

High purity alumina production by leaching-ion exchange process: Design and flowchart proposal

Growing demand for high-purity Al2O3 for the electronic market and green energy production, allied with the need to decrease waste generation and dam use, will impact the future of mining, and new processes should be developed. The present study aimed to develop a hydrometallurgical process to obtain high-purity Al2O3 from bauxite. Among the samples studied, BX03 had the highest Al2O3 (63.8 %) and lowest Fe2O3 content (4.3 %). Different acids were evaluated – H2SO4, HCl, HNO3, and H3PO4 – and the H2SO4 reaction achieved all Al leaching with the best technical–economic analysis (TEA). Purification experiments were carried out with ion exchange resins in batch reactions. The best purification parameters were 4 h of contacting time and mass of resin/volume of solution ratio as 1/10 at 45 °C in two stages. The iminodiacetate resin (Lewatit TP 207) achieved the best results and removed all Fe ions without losses. High-purity Al2O3 was further obtained by precipitation with NH4OH after calcination. Considering the leaching step costs, the proposed process may achieve up to US$ 63,022.91 in profit.

Technical-economic analysis and optimization of multiple effect distillation system by solar energy conversion as the heat source

The utilization of multi-effect distillation (MED) in thermal desalination processes is more widespread owing to lower energy consumption. The focus of this paper is to optimize the performance of MED through process optimization. It aims to identify the optimal operating conditions that result in maximum water and power production. Additionally, it investigates the potential of using solar renewable energy as a substitute for the current fossil energy source. Subsequently, a switch to solar energy was made with a focus on an economically viable approach. The research explored the best-suited collector and fluid for heat transfer among the 8 types of molten salt for use in the collector. Subsequently, an economic and sensitivity analysis was conducted using this procedure. The outcomes indicated that by enhancing the stated procedure, it was found that 27.93 Megawatt (MW) of heat would be required when 6938 ton/h of natural gas are burned. Additionally, the 4-effect MED process produced 6.123 MW of electricity and 116.5 cubic meters per hour (m3/h) of freshwater. The gain output ratio (GOR) of the process saw an uptick from 2.75 to 3.328, whereas MED efficiency showed progress from 13.76 to 49.218 %. The parabolic trough collector (PTC) collector outperforms the linear Fresnel collector (LFC) and solar dish (SD) collector in terms of efficiency among other results. To store heat for the rest of the day and night and supply thermal energy for the entire process, 155,542 square meters (m2) of this collector are necessary. Additionally, in regards to the thermal fluid of the PTC collector, coastal chemical registered heat transfer salt (HITEC salt), a commercial mixture of solar salt, has exhibited superior performance over other molten salts (for a total expenditure of 50 million dollars over two decades). In addition, the economic analysis has indicated a return rate of 32.46 % for the investment and a capital recovery period of 3.08 years for the process. The implementation of the mentioned process in renewable mode results in the avoidance of 18.5 tons per hour (ton/h) of carbon dioxide (CO2) emissions.

Enhancing corn stover to bio-jet fuel process: Valorizing lignin-enriched residue for energy, economic, and environmental benefits

Bio-jet fuels are considered as a highly promising strategy for minimizing carbon emissions in the aviation sector. This study presents a scheme for producing bio-jet fuel from corn stover through aqueous phase conversion, focusing on the economics and environmental performance of various lignin utilization technologies. Three scenarios were simulated using Aspen Plus, each integrating a different approach: lignin hydrothermal conversion to jet fuel range arenes (LtoA), lignin gasification-syngas fermentation to ethanol (LtoE), and lignin direct combustion (LC). The energy conversion rates of the three cases are 32.75 %, 32.67 %, and 31.44 %, in that order. Technical-economic analysis and life cycle assessment were conducted for each scenario. The minimum jet fuel selling prices (MJFSP) for the three scenarios range between 2050 and 2562 $/t, 2095–2620 $/t, and 2024–2529 $/t, with greenhouse gas (GHG) emissions reduced by 33 %, 383 %, and 37 % compared to fossil jet fuel, respectively. Steam stripping for furfural production is the largest energy consumer, hindering economic improvement and GHG emission reduction due to inefficient furfural yield. The use of sulfuric acid and NaOH as catalysts contributes significantly to 37 % of greenhouse gas (GHG) emissions and 79 % of human toxicity emissions among other environmental impacts. The development of green solvents and the enhancement of lignin conversion rates could further improve the economic and environmental performance of bio-jet fuel.

Unfavourable scenario analysis of compensation mechanisms for excessenergy in self-consumption photovoltaic installations in the Spanishresidential sector

Self-consumption photovoltaic installations in the residentialsector have great potential to mitigate the emissions associatedwith the current high consumption of fossil fuels. However, fewstudies analyse the technical and economic performance of theseinstallations as a function of the electricity tariff contracted by theprosumer.This study provides a first approach to this idea, as well asanalysing an emerging tariff in the Spanish electricity market, suchas the virtual battery (solar piggy bank or net billing), which allowsthe entire bill to be offset with photovoltaic surpluses.A technical-economic analysis of a self-consumption photovoltaicinstallation connected to the grid is carried out for different peakpower values, as well as for different consumption profiles anddifferent electricity tariffs.The results show the importance of considering the prosumer'sconsumption habits, as these directly influence the performance ofthe installation. Thus, it is not possible to obtain a single optimalsolution for all cases. Among other conclusions, it was found thatfor surplus-to-consumption ratios in the range of 130-180 % andabove, the virtual battery tariff is the best economic option.

A technical-economic analysis and optimization of a direct molten salts linear Fresnel plant

A technical-economic analysis and optimization of a direct molten salts linear Fresnel plant

Análise técnico-econômica da implantação de um sistema de aquecimento solar para suprir a demanda de água quente dos vestiários de um abatedouro de aves

The use of electricity to heat bath water is still quite common in Brazil, especially in the South and Southeast regions. This practice represents about 24% of the total energy consumption in the residential sector. Additionally, its usage is concentrated between 6 and 9 PM, leading to serious issues in energy generation and distribution during this interval. Given the importance of rationalizing the electricity consumption, the aim of this paper was to conduct a technical-economic analysis for the implementation of a hybrid solar heating system to supply the demand for hot water in the bathrooms of a poultry slaughterhouse located in the Western region of Paraná. For this, different scenarios of usage were developed, where the type of solar collector and the auxiliary power source were varied and a comparison between the alternatives and the conventional water heating systems was made. A calculation routine based on the F-Chart method was used to size the alternative systems. The Net Present Value (NPV), the Internal Rate of Return (IRR) and the discounted Payback were used as decision-making criteria. All configurations sized in this study were proved to be viable. However, the most interesting one, from a technical-economic point of view, was the combination of the flat-plate solar collectors and the electric auxiliary power source. The comparison of this scenario with the conventional source showed an NPV of R$ 92,916.84, an IRR of 59.9%, and a payback period of 1 year and 11 months.

Techno-economics of multi-stage reverse electrodialysis for blue energy harvesting

Multi-stage reverse electrodialysis (MSRED) offers a promising way for efficient salinity gradient energy harvesting. Here, an improved model of the MSRED system under serial control strategy is proposed. The technical–economic analysis is conducted with considering discount, depreciation and different regional tax and electricity price levels under the maximum net power output conditions. Results reveal that net power output and energy efficiency both increase first with increasing stage numbers, reach their maximum values, and then decrease. For 5 M/0.05 M solutions, the optimal net power output of 4.98 kW is obtained at the stage number n = 12. The optimal stage number corresponding to the maximum net power increases with increasing feed solution concentrations. Due to the compromise between net power generation and capital cost, there exist optimal stage numbers leading to the lowest LCOE and largest NPV, respectively. Higher feed solution concentration can significantly decrease the system LCOE and increase the NPV. The optimal stage number corresponding to the maximum NPV increases with increasing feed solution concentrations. In Germany, for 5 M/0.05 M solutions, the lowest LCOE of 0.061 €·kWh−1 is achieved at n = 3 while the highest NPV over the system lifecycle of 52,005 € is obtained at n = 8. Lower tax, higher electricity price, appropriate membrane price and stage numbers, and high salinity gradient sources can significantly accelerate the commercial completeness of the MSRED systems.

A technical-economic analysis of integrating vine prunings energy conversion systems for CHP production in local wineries

This study proposes the energy conversion of vine prunings to supply energy to local wineries, with a focus on the Riunite & CIV branch winery located in Carpi (Modena, Italy), exploring the possibility of generating both electricity and heat through biomass gasification. A Matlab-Simulink model is used to evaluate the energy savings that can be achieved when an energy storage system is coupled with the combined heat and power generation system. Within this context, the results showed that it is possible to save ≈\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\approx $$\\end{document}30% of the electricity and ≈\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\approx $$\\end{document}60% of the thermal energy demanded by the winery. However, the economic viability of the project is hindered by high investment and operation costs. DPB is strongly affected by the cost of biomass and the energy prices, resulting in a profitable investment for electricity prices higher than 0.30 ÷>\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\div>$$\\end{document}0.57 €/kWh according to the different scenarios investigated.

Investigation of solar accommodation via storage configuration in district heating system based on granularity analysis

In the pursuit of achieving carbon neutrality, it is essential to advance the broad accommodation of renewable energy for the realization of a low-carbon district heating system (DHS). The heat storage configuration serves as an effective assurance for facilitating the accommodation of renewable energy in DHS. This paper analyzes the impact of heat storage configuration on the accommodation of solar energy in DHS, employing a granularity analysis method. This study proposes an optimization method for determining the maximum solar energy accommodation rate in solar-assisted DHSs using the granularity analysis method. Furthermore, this study optimizes the heat storage capacity configuration to facilitate varying ratios of solar energy accommodation. Finally, a technical-economic analysis of the solar-assisted DHS is performed in the context of rising energy cost. The case study reveals that greater granularity leads to a higher solar energy accommodation rate. Specifically, when the granularity increases from 0.43% to 22.22%, the solar energy accommodation rate increases by 8.01%. Moreover, the heat storage capacity configuration increases with the increase of the solar energy accommodation rate, while the heat storage capacity required to accommodate per unit of solar energy decreases. Additionally, as the granularity increases from 0.43% to 22.22%, the heat storage capacity configuration under the same solar energy accommodation ratio increases gradually. This study explores the potential of granularity-based heat storage configuration optimization in promoting solar energy accommodation and achieving the economy of DHS, which is of great significance for the decarbonization of DHS.

Development of a simulation model to carry out technical-economic analysis of a food waste valorization process.

Worldwide interest in food waste has been grown over the years. According to the FAO about one third of all food produced for human consumption in the world is lost or wasted each year, amounting to about 1,6 billion tons per year. Food waste can become a source of valuable compounds which may be used as ingredients in cosmetics, pharmaceuticals, or food products. This study aims to evaluate the use of a process simulation software, specifically SuperPro Designer®, to carry out a technical-economic analysis of an orange waste valorization process. Specifically, the extraction of free sugars, essential oils, antioxidant phenolic compounds and pectin were digitally replicated by reproducing the corresponding material and energy balances. An economic and environmental assessment were carried out to evaluate the feasibility of the biorefinery modeled. The amount of orange peel processed, utilities and raw material costs were identified as significant parameters in the analyses performed. A sensitivity analysis was carried out to evaluate the profitability patterns under different operating conditions. Meanwhile, the aim of the environmental assessment is to define a disposal inventory, which is the starting point for a life cycle assessment. As a result, SuperPro Designer® can be a valuable tool in the designing and optimizing food waste treatment systems, providing detailed descriptions of the process performance, and enabling cost-effective and sustainable waste management practices. Indeed, the simulation accurately reproduced all the steps involved, identifying the total investment and the related economic parameters, as well as the outputs and the resulting disposal inventory.

Natural biochar catalyst: Realizing the co-valorization of waste cooking oil into high-quality biofuel and carbon nanotube precursor via catalytic pyrolysis process

Valorizing renewable precursors into high-quality biofuel and functional carbon nanomaterials can considerably improve the economic viability. Here, we propose a process for integrated production of high-quality biofuel and carbon nanotubes from waste cooking oil via catalytic pyrolysis coupling with chemical vapor deposition (CVD) technology. The natural biochar catalyst demonstrates excellent deoxygenation performance and good stability in catalytic pyrolysis process. The alkali/alkaline earth metal species (AAEMs) content in biochar catalysts has a strong correlation with the selectivity of esters and hydrocarbons in bio-oil. The biofuel obtained under optimal conditions exhibited potential as a precursor for jet fuel. The CVD process convert pyrolysis gas into carbon nanotubes with yield of 2.13%. The technical–economic analysis demonstrated the feasibility of the integrated process, projecting profitability and substantial total profit over a ten-year period. Overall, this study improves the economic viability of the waste cooking oil pyrolysis process and supports its wider commercial application.

Development of a Tool for Sizing and Technical–Financial Analysis of Energy‐Storage Systems Using Batteries

In this article, an innovative approach is presented to the sizing and technical–economic analysis of battery energy‐storage systems (BESS) designed for customers in the free energy market in Brazil. The tool enables the integration of photovoltaic (PV) energy sources and includes a comparison between the BESS + PV system and diesel generators. Integrating the computational capabilities of Microsoft Excel in the backend and the intuitive interface of PowerApps in the front end, the sizing process is based on analyzing historical energy invoices spanning at least 12 months or loading data with a 1 h measurement interval. The data discretization over the 8760 h of the year, considering the consumer's load profile, is facilitated by the PowerApps interface, providing a comprehensive visualization of the technical‐economic sizing results for BESS. A case study is conducted for a commercial load with a specific tariff for free energy market customers, revealing viable solutions for BESS compared to diesel alternatives. In this approach, it is aimed to simplify the analysis and decision‐making process, offering a valuable tool for power system engineers to evaluate sustainable and economically viable solutions in the Brazilian free energy market.

Subsidy policies towards zero-emission bus fleets: A systematic technical-economic analysis

We establish a bus market evolution model to explore the implications of subsidy policies in Hong Kong (HK) for the transition to a zero-emission bus (ZEB) fleet using an unsubsidized case as the benchmark scenario. Using the system dynamics (SD) approach, we capture the intricate feedback mechanisms among market share dynamics, cost considerations, consumer preferences, and competitive interactions within the bus market. These interactions are encapsulated within three pivotal feedback loops: scale economy, public acceptance, and bus market competition. We systematically integrate the HK-specific features of hydrogen buses (H-buses), battery electric buses (E-buses), and diesel buses (D-buses) from technical and economic perspectives and compare them to the benchmark scenario. The results show that only 66% of the bus fleet would be ZEBs by 2050, and this underscores the necessity for governmental financial incentives to expedite the transition to a fully zero-emission fleet. Furthermore, we evaluate various ZEB subsidy policy alternatives in terms of timing, intensity, and recipients. The analysis suggests that policies offering long-term and low-intensity subsidies are most beneficial, taking into account the cumulative effects and inherent delays associated with policy implementation. Importantly, the study highlights the critical balance that policymakers must achieve between short- and long-term objectives, especially given the counter-intuitive outcomes observed in the early stages of policies favoring H-buses exclusively. This study provides valuable policy insights for policymakers and upstream energy companies in HK, with potential applicability in wider real-world contexts.

Bibliometric Analysis of Urban Coastal Development: Strategies for Climate-Resilient Timber Housing

Urban development in coastal areas has become increasingly important due to the climate crisis and its effects on sea level rise and extreme events, which increased the vulnerability of coastal zones. Therefore, it is important to analyze possible sustainable development techniques in urban planning and residential housing construction based on low-carbon footprint materials such as timber. These techniques should be capable of mitigating the effects of flooding and uncontrolled rises in coastal areas, as well as identifying normative and economic differences in their application in the Chilean context. For this purpose, a bibliometric analysis of 3882 articles selected from the Web of Science database between 1987 and 2022 was conducted, allowing us to identify a range of possible solutions to be developed in the study area. This includes evaluating their potential for normative application and a cost analysis of these solutions. In this regard, housing solutions such as amphibious houses and houses on stilts are two types of flood-resistant homes that are gaining popularity worldwide. Following the technical–economic analysis, it was observed that the solution on stilts can be up to 50% more cost-effective to implement in Chile. However, both options offer a promising solution to minimize the risks of coastal flooding and should be taken into account in the urban planning of coastal areas.

Technical–Economic Analysis for Ammonia Ocean Transportation Using an Ammonia-Fueled Carrier

This study performed a technical–economic analysis for ship-based ammonia transportation to investigate the feasibility of international ammonia transportation. Ammonia is considered to be a vital hydrogen carrier, so the international trade in ammonia by ship will considerably increase in the future. This study proposed three scenarios for transporting ammonia from the USA, Saudi Arabia, and Australia to South Korea and employed an 84,000 m3 class ammonia carrier. Not only traditional very low sulfur fuel oil (VLSFO)/marine diesel oil (MDO) but also LNG and ammonia fuels were considered as propulsion and power generation fuels in the carrier. A life-cycle cost (LCC) model consisting of capital expenditure (CAPEX) and operational expenditure (OPEX) was employed for the cost estimation. The results showed that the transportation costs depend on the distance. The unit transportation cost from the USA to South Korea was approximately three times higher than that of Australia to South Korea. Ammonia fuel yielded the highest costs among the fuels investigated (VLSFO/MGO, LNG, and ammonia). When using ammonia fuel, the unit transportation cost was approximately twice that when using VLSFO/MDO. The fuel costs occupied the largest portion of the LCC. The unit transportation costs from Australia to South Korea were 23.6 USD/ton-NH3 for the LVSFO/MDO fuel case, 31.6 USD/ton-NH3 for the LNG fuel case, and 42.9 USD/ton-NH3 for the ammonia fuel case. This study also conducted a sensitivity analysis to investigate the influence of assumptions, including assumed parameters.