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Microgrids and hybrid renewable energy systems play a crucial role in today's energy transition. They enable local power generation and distribution, reducing dependence on large centralized infrastructures, can operate independently or connected to a grid, and can provide backup power, thus increasing system resilience. In addition, they combine multiple renewable energy sources, such as solar, wind, hydro, and biomass, to maximize the efficiency and reliability of the supply, and are also adaptable to location-specific conditions, taking advantage of locally available energy resources and reducing the need for energy imports. Moreover, they contribute to decarbonization goals by offering a cleaner and more sustainable alternative. In this article, a documentary review is presented on the interaction of Homer Pro software 3.16.2 (July 2023), used for the design of hybrid renewable energy systems (HRES), with other methods of optimization or sizing. Allusion is made to the type of architecture in the most prominent clean and fossil source configurations, the levelized cost, net annual cost, and maintenance and capital investment cost. A comparison is made among the works reported in the last five years regarding the use of this software tool, based on load demand, geographical area, renewable energy sources, fossil sources, and objective functions, applied to the educational, rural, and industrial sectors. It is shown that India is one of the countries that has reported the most number of HRES techno-economic environmental analysis works, and that the case studies have focused approximately 47% on rural areas, 20% on educational agencies, 14% on commerce and industry, and 29% on urban buildings. [ABSTRACT FROM AUTHOR]

Frequency response services are one of the key components used by major electrical networks worldwide, acting to help control the frequency within set boundaries. Battery Energy Storage Systems (BESSs) are commonly deployed for this purpose; however, their potential is limited by susceptibility to cycle-based degradation and widely reported safety incidents. Flywheel Energy Storage Systems (FESSs) do not share these weaknesses and hence could be a potential candidate for longer-term participation in frequency response markets. This study presents the most in-depth and wide-ranging techno-economic analysis of the feasibility of FESSs for frequency response to date. Standalone FESSs are shown to be economically viable across a range of different specifications, achieving a positive Net Present Value (NPV) under varying economic conditions. At a capital cost of 500 GBP/kW with a discount rate of 4%, a 5C FESS can achieve an NPV of GBP 38,586 as a standalone unit. The complex trade-offs when considering hybridising FESSs and BESSs for this application are also investigated in-depth for the first time, again showing positive changes to NPV under various scenarios. Conversely, under some conditions, hybridisation can have a significant negative impact, showcasing the optimisation needed when considering hybrid systems. The impact of introducing a hybrid BESS varies from a low of decreasing the NPV of the system by GBP 97,955 to a high of increasing the NPV by GBP 119,621 depending on the configuration chosen. This comprehensive work provides the foundations for future research into FESS deployment for frequency response services and shows for the first time the circumstances under which deployment for this application would be both technically and economically viable. [ABSTRACT FROM AUTHOR]

Carbon geological storage (CGS) is one of the key processes in carbon capture and storage (CCS) technologies, which are used to reduce CO2 emissions and achieve carbon-neutrality and net-zero emissions in developing countries. In Thailand, the Mae Moh basin is a potential site for implementing CGS due to the presence of a structural trap that can seal the CO2 storage formation. However, the cost of CGS projects needs to be subsidized by selling carbon credits in order to reach the project breakeven. Therefore, this paper estimates the economic components of a CGS project in the Mae Moh basin by designing the well completion and operating parameters for CO2 injection. The capital costs and operating costs of the process components were calculated, and the minimum carbon credit cost required to cover the total costs of the CGS project was determined. The results indicate that the designed system proposes an operating gas injection rate of 1.454 MMscf/day, which is equivalent to 29,530 tCO2e per year per well. Additionally, the minimum carbon credit cost was estimated to be USD 70.77 per tCO2e in order to achieve breakeven for the best case CGS project, which was found to be much higher than the current market price of carbon credit in Thailand, at around USD 3.5 per tCO2e. To enhance the economic prospects of this area, it is imperative to promote a policy of improving the cost of carbon credit for CGS projects in Thailand. [ABSTRACT FROM AUTHOR]

The basic requirements for the design of a switchgear for main 35–220 kV step-down substations are reliability and efficiency. Switchgear circuits are chosen depending on the number of supply and transit lines and transformers, the substation's place in the power supply system, and the area that can be allocated under the substation construction. The substation switchgear's reliability depends on the circuit type and the equipment to be installed. When designing, as a rule, standard substation switchgear circuit solutions are chosen with often unreasonably overstated reliability indicators and, as a consequence, capital costs. This paper explores the issues of automated choice of the best option for the 35–220 kV substation switchgear circuit, considering its structural reliability and additional costs for the area allocated under the electrical unit. A distinctive feature of the work is a comprehensive accounting of the reliability indicators of the substation and the influence of the layout of switchgear circuits as a whole on the performance indicators of future electrical installations. The developed technique is used at the pre-design stages and allows for reducing further capital, maintenance, and repair costs for electrical units by up to 14.5%. The developed approach is implemented in the original TER CAD software product. [ABSTRACT FROM AUTHOR]

The biogas sector in Europe and Italy is attracting growing investment, combining agricultural activity, the circular economy, and renewable energy production. Firms in the sector widely use debt capital and, for this reason, there is a need to evaluate the structure of investments, financing, and debt service capacity calculated by applying interest coverage ratios (ICRs). ICRs are widely used by banks in granting loans, and calculation of ICRs allows managers and policy makers to correctly evaluate firms' performance in the sector. In this research, based on a sample of 160 observations, the structure of investments and sources of financing of firms in the biogas sector, operating in northern Italy, are analyzed. ICRs are calculated with different approaches to establish which ICRs provide the most reliable results in the application. The research analyzes the correlations and highlights significant differences between ICRs. The research highlights some important findings: (a) the NWC is negative in 109 out of 160 observations and, therefore, constitutes a source of financing in the majority of observations; (b) ICRs based on EBITDA and CF are above the threshold value of "1" in 143 and 145 observations, respectively, while ICRs based on EBIT, OCF, and UFCF are above the threshold value of "1" in 132, 133, and 122 observations, respectively. The research allows the conclusion that the ICRs based on EBITDA and CF tend to overestimate results; ICRs based on EBIT, OCF and UFCF are preferable, and can therefore be applied by managers, banks, and policy makers and be used as debt covenants. For the calculation of the repayment of the NFP, the research has highlighted that ICRs in which the cost of the debt is deducted from the numerator are preferable. The research can thus be usefully applied and expanded to other territories, or by considering a larger sample with the aim of inferring conclusions of general validity. [ABSTRACT FROM AUTHOR]

A promising method of energy storage is the combination of hydrogen and compressed-air energy storage (CAES) systems. CAES systems are divided into diabatic, adiabatic, and isothermal cycles. In the diabatic cycle, thermal energy after air compression is discharged into the environment, and the scheme implies the use of organic fuel. Taking into account the prospects of the decarbonization of the energy industry, it is advisable to replace natural gas in the diabatic CAES scheme with hydrogen obtained by electrolysis using power-to-gas technology. In this article, the SENECA-1A project is considered as a high-power hybrid unit, using hydrogen instead of natural gas. The results show that while keeping the 214 MW turbines powered, the transition to hydrogen reduces carbon dioxide emissions from 8.8 to 0.0 kg/s, while the formation of water vapor will increase from 17.6 to 27.4 kg/s. It is shown that the adiabatic CAES SENECA-1A mode, compared to the diabatic, has 0.0 carbon dioxide and water vapor emission with relatively higher efficiency (71.5 vs. 62.1%). At the same time, the main advantage of the diabatic CAES is the possibility to produce more power in the turbine block (214 vs. 131.6 MW), having fewer capital costs. Thus, choosing the technology is a subject of complex technical, economic, and ecological study. [ABSTRACT FROM AUTHOR]

Rising shares of variable wind and solar generation in decarbonized electricity systems motivate the development of novel power cycles employing unconventional fuels. Innovative designs must be highly flexible and profitable at low capacity factors, requiring a simple process layout and low capital costs. Fuel supply infrastructure represents a significant additional capital cost, which is often ignored in economic assessments of gas-fired power plants. When these capital costs are included, liquid fuels such as NH3 or MeOH gain relevance despite their high production costs because they are cheap to store and distribute. In addition, chemically recuperated power cycle designs upgrade these fuels with waste heat from the gas turbine exhaust, avoiding a capital-intensive bottoming cycle while achieving high thermal efficiencies. This work presents an exergoeconomic benchmarking of different large-scale power plants and their fuel supply infrastructure. The results show that chemically recuperated cycles using MeOH become competitive relative to natural-gas-fired combined cycles with fuel storage in salt caverns at capacity factors below 32% if seven-day storage is required and plants are located 500 km from the fuel source. NH3 can compete with H2 at a higher capacity factor of 47% because of the high cost of storing H2, while a CO2 price of 140 EUR/ton is required for NH3 to outperform MeOH as a fuel. In cases where salt cavern storage is unavailable, or the energy security of multi-week fuel storage is highly valued, liquid fuels present a clearly superior solution. [ABSTRACT FROM AUTHOR]

Published forecasts underestimate renewable energy capacity growth and potential cost reductions, creating uncertainty around investment decisions and slowing progress. Scenario-based projections diverge widely, driven by variations in modelling techniques and underlying assumptions, with policy-based models typically being overly conservative. With historical generation capacity and cost data readily available, this research demonstrates that data-driven approaches can be leveraged to improve long-term capacity and cost forecasts of solar, wind, and battery storage technologies. Unlike exponential growth models prevailing over shorter time scales, logistic curves requiring asymptotic limits, or machine learning algorithms dependent on extensive datasets, this analysis demonstrates that temporal quadratic regressions are a better starting point to represent capacity growth trends over two to three decades. When coupled with published learning rates, trend-based capacity forecasts provided tighter and lower capital and levelized cost of energy outlooks than most reviewed scenarios, with photovoltaics global average levelized cost of energy reducing from 0.057/kWh to below USD 0.03/kWh by 2030 and below USD 0.02/kWh by 2040. Greater transparency on manufacturing ecosystems is proposed so that more advanced analytical techniques can be utilized. This analysis indicates that without direct interventions to accelerate the growth in wind power generation, global renewable energy technology deployment will fall short of the generation capacities required to meet climate change objectives. [ABSTRACT FROM AUTHOR]

The increasing environmental concerns and dependence on fossil fuel-based energy sectors necessitate a shift towards renewable energy. Off-grid communities can particularly benefit from standalone, scaled renewable power plants. This study developed a comprehensive techno-economic framework, analyzed the objective metrics, and assessed the influence of economies of scale in solar PV power plants to electrify off-grid communities, taking Baluchistan, Pakistan, as a pilot case. Simulations and analyses were performed using the System Advisor Model (SAM). The results indicate a noteworthy reduction in the levelized cost of energy (LCOE) with increased power generation capacity. It was observed that utilizing bi-facial modules with single-axis tracking leads to a more cost-effective LCOE compared to the relatively expensive dual-axis trackers. The main cost factors identified in the analysis were capital costs, installed balance of plant (BOP), mechanical, and electrical costs. Notably, the disparity between the highest and lowest LCOE values across the six different power generation pathways amounted to approximately 38.5%. The average LCOE was determined to be 2.14 USD/kWh for fixed-mounted plants, 1.79 USD/kWh for single-axis plants, and 1.74 USD/kWh for dual-axis plants across the examined power generation capacity range. The findings can serve as a valuable benchmark, specifically for regional key stakeholders, in making informed investment decisions, formulating effective policies, and devising appropriate strategies for off-grid electrification and the development of renewable energy value chains. [ABSTRACT FROM AUTHOR]

There is mounting evidence that, unless greenhouse gas (GHG) emissions fall back quickly, the goals outlined by the 2015 Paris Agreement to keep the global temperature rise well below 2 °C and preferably 1.5 °C will not be met. In response to these concerns, direct air carbon capture and storage (DACCS) technologies are gaining research and development attention. This article provides a thorough comparison of the two leading DACCS variants and reports on their status among major research and policy institutions worldwide. By translating the operating and capital costs to the Australian context, we assess the viability of DACCS implementation using either cheap renewable or legacy fossil energy to power CO2 extraction plants. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical programming approach for the strategic planning of hydrogen production from renewable energies and its use in electric power generation in conventional technologies. The proposed approach aims to determine the optimal selection of the different types of technologies, electrolyzers and storage units (energy and hydrogen). The approach considers the implementation of an optimization methodology to select a representative data set that characterizes the total annual demand. The economic objective aims to determine the minimum cost, which is composed of the capital costs in the acquisition of units, operating costs of such units, costs of production and transmission of energy, as well as the cost associated with the emissions generated, which is related to an environmental tax. A specific case study is presented in the Mexican peninsula and the results show that it is possible to produce hydrogen at a minimum sale price of 4200 $/tonH2, with a total cost of $5.1687 × 106 and 2.5243 × 105 tonCO2eq. In addition, the financial break-even point corresponds to a sale price of 6600 $/tonH2. The proposed model determines the trade-offs between the cost and the emissions generated. [ABSTRACT FROM AUTHOR]

One year of high-resolution driving data from a sample of 333 instrumented gasoline passenger vehicles are used to create a trip inventory of U.S. vehicle travel requirements. A set of electric vehicles (EVs) is modeled, differing in battery size (kWh), recharging power (kW), and locations for charging when parked. Each modeled EV's remaining energy is tracked while traversing the entire sample's trip inventory in order to estimate how well each EV meets all U.S. driving requirements. The capital cost of refueling infrastructure is estimated per car, for gasoline and for each analyzed combination of charging station locations. We develop three metrics of the ability of different EV characteristics to meet trip requirements: the percentage of trips successfully met by each modeled EV, the number of days that the driver must "adapt" EV use to meet more demanding trip requirements, and the total driver time required for refueling. We also segment the market of trip patterns per car, finding that 25% to 37% of the vehicle population could meet all their drivers' trip needs with a smaller-battery EV combined with community charging. This potential combination of EVs and charging would enable lower-price EVs and lower-cost recharging power, and would broaden EV availability to groups for whom today's EVs and charging configurations are less accessible. [ABSTRACT FROM AUTHOR]

In electrical power engineering, elements such as reliability analysis, modeling, and optimization for complex systems are of the utmost importance. Although there exist myriad studies regarding reliability optimization with conventional methods, researchers are still seeking to find more efficient and accurate methods to address the issue of the redundancy allocation problem. To that effect, an ideal power energy management approach is put forward for the operation of a hybrid microgrid system with different kinds of productions. In the present study, we suggest three algorithms in order to optimize the series-parallel power energy system: the Firefly (FA), Bat (BA), and Interior Search (ISA) algorithms. Moreover, the reliability estimate of the system is solved with the Ushakov algorithm (UMGF). The components may completely fail, which decreases their performance rate. Furthermore, the optimization results are achieved using objective functions that include the total cost of the system, emission gases (NOX, SO2, and CO2) of the power production from fuel cells, diesel generators, and gas turbines, and take into consideration the dependability indices. Devices used in power subsystems are characterized based on their dependabilities, performances, capital costs, and maintenance costs. Reliability hinges on a functioning system, which naturally entails meeting customer demand; as a result, it is influenced by the accumulated batch curve. This method provides an idea with regards to the economic cost optimization of microgrid systems. Finally, we present the results of numeric simulations. [ABSTRACT FROM AUTHOR]

In emerging countries, energy service users generally pay high rates of return to transmission system operators (TSOs). One of the causes of this situation is the application of the CAPM with the comparable beta method when estimating the cost of equity in the WACC. The purpose of this article is to present a new methodology for calculating the cost of equity of TSOs in Colombia. To achieve this objective, a multifactor model has been built to explain the variation in returns on the electric utilities portfolio in Colombia between April 2008 and March 2022 and then recalculate the WACC approved by the country's regulatory commission. It was found that, in addition to the estimated market risk in the CAPM, there is a risk due to the regulatory framework and changes in interest rates, which helps to explain 73% of the variations in the electric utilities portfolio, resulting in a lower cost of equity, and therefore a lower WACC of 5.28% compared to the WACC estimated by the regulator of 11.79% in 2019. These results can support regulatory commissions in emerging countries in establishing a more accurate rate of return for users. [ABSTRACT FROM AUTHOR]

The paper is aimed to develop a wireless alternating current (AC) power monitoring module which features the advantage of cost-effectiveness and sufficient reliability for the proposed AC power monitoring Internet of Things (IoT) system. The novel wireless AC power monitoring module consists of both ZMPT101B voltage sensor and ACS712-20 current sensor; a 16-bit analog-to-digital (ADC) ADS1114 with I2C interface and WeMos D1 Mini Wi-Fi module were integrated for monitoring refrigerator and air conditioner appliances with the ratings of single-phase 110/220 VAC, respectively. First, both analog readings of V/I sensors for AC appliances are converted into data streams in compliance with I2C (inter-integrated circuit) protocol, and are forwarded to a WeMos D1 Mini Wi-Fi module for the corresponding values of instantaneous electric power and energy, power factor (pf), and frequency well programmed in the built-in ESP8266EX IoT-based microcontroller unit (MCU) based on the well-known AC power fundamentals. All of the important AC power parameters are sent to the ThingSpeak IoT platform through Wi-Fi network. The visualization of voltage, current, electric power and energy, pf, and frequency is illustrated in the ThingSpeak IoT platform. Both close agreement and confidence of the proposed AC power monitoring IoT system for both refrigerator and air conditioner are evaluated with two CM3286-1 AC Power Meters. Taking the commercialized CM3286-1 instrument as reference, the values of mean absolute percentage error (MAPE) for above six electrical parameter readings are all less than 2%. The evaluation results illustrate sufficient closeness of agreement and confidence for the proposed wireless AC power monitoring IoT system for in situ monitoring AC appliances with single-phase 110/220 VAC ratings. Furthermore, the cost of the proposed AC power monitoring module is less than 100 USD, which makes the novel module more cost-effective than commercialized AC power meters which generally cost over 1000 USD. The novelties of the work are the following: (1) the introduction of ADS1114 provides I2C interface directly for Wi-Fi module to reduce the capital cost of the proposed wireless AC power monitoring module; (2) the sufficient confidence of the proposed AC power monitoring IoT system has been validated with closeness of agreement as compared to the commercialized CM3286-1 AC Power Meters. These make the assessment action of environmental, social, and governance (EGS) for stakeholders much more feasible with the advantages of cost-effectiveness and sufficient confidence. [ABSTRACT FROM AUTHOR]

Operation strategies for a park-level integrated energy system (PIES) in terms of carbon prices and feed-in tariffs, have not been adequately studied. This paper addresses this knowledge gap by proposing operation strategies based on the PIES driven by biogas, solar energy, natural gas, and the power grid. Meanwhile, the electricity-driven dispatching strategy (EDS), thermal-driven dispatching strategy (TDS), cost-driven dispatching strategy (CDS) are compared to assess their impacts on operation cost, carbon dioxide emissions, etc. The flexibility and complementarity of the three operation strategies in energy supply are analyzed in detail. The results indicated that biogas was the main energy supply fuel, accounting for 46% to 72% of the total energy supply. About 33% to 54% of electricity was transmitted to the grid each month using the TDS. The annual initial capital cost of the CDS was only 1.39% higher than that of the EDS. However, the annual operation cost of the EDS was 16.86% higher than that of the CDS. The emissions of the EDS were the lowest, and the CDS had 38.51% higher emissions than the EDS. In the CDS, the ratio of carbon emission costs to operation costs was as high as 0.80 when the carbon tax reached USD 100/ton. The carbon tax had a greater impact on the CDS than the other strategies. Feed-in tariffs had a greater impact than the carbon tax on the TDS. This study provides an effective method for the selection of optimal operation strategies in regards to carbon prices and feed-in tariffs. [ABSTRACT FROM AUTHOR]

The present study investigates low-grade heat utilization in ejector refrigeration systems under hot climatic conditions. A variable area ejector is used to maximize the harvested heat from the generator of the solar system at peak times. Exergy, economic, and exergoeconomic analyses are conducted to evaluate the performance of the system. A thermodynamic model of the system has been developed using Ebsilon Professional software. Available experimental and theoretical data validate the results. The effects of properties of the working fluids, ejector geometry, and operation conditions are also evaluated. It was found that the coefficient of performance of the system reached 0.45 at a generator pressure of 3 bars. Furthermore, it was noticed that the overall exergy efficiency could be increased for a fixed generator temperature while increasing the ejector area ratio. A value of 21% exergetic efficiency was calculated for the system. The exergoeconomic analysis of the system demonstrated that heat exchangers are required to be improved thermodynamically at the expense of the capital investment cost. [ABSTRACT FROM AUTHOR]

Process heating represents about two-thirds of the energy that the industry sector consumes worldwide; this energy comes primarily from burning fossil fuels. There is a wide variety of processes for which solar technologies can supply energy. Within these technologies, the CSPth Central Tower produces heat at temperatures about 600 °C, making it suitable for high-temperature processes. A CSPth Central Tower can be combined with a fuel-based system to form a CSPth Hybrid Central Tower system, which results in a high-reliable energy source with low rates of CO2 emissions. In this work, the levelized cost of heat (LCOH) of the CSPth Hybrid Central Tower technology was calculated. SolarPILOT was used to design and evaluate the CSPth Central Tower; fuel consumption was calculated using a steady-state energy balance. The LCOH was evaluated considering the CO2 prices recommended by the High-Level Commission on Carbon Pricing. The analysis shows that this technology can be highly competitive and, in certain cases, shows lower LCOH than fuel-based systems. However, these cases depend on reasonable CO2 prices, low costs of capital (≈5%), and efforts to reduce the capital expenditure, which can nowadays be possible for CSPth Hybrid Central Tower systems designed with large solar multiples. [ABSTRACT FROM AUTHOR]

Recent economic anomalies, including the unprecedented lockdown generated by the COVID-19 crisis, have demonstrated that the weighted average cost of capital (WACC) remains an actual topic in the financial literature and in practice. Companies operate in an increasingly volatile environment, due to twin transitions and interlinked crises, and so they must have specific tools for measuring risk and profitability, in order to enable them to have a sound financial policy. Based on the earlier results obtained by Modigliani and Miller (1963), Harris and Pringle (1985), and Farber, Gillet, and Szafarz (2006), this study shows the relationship between WACC and interest rate. It offers a modified WACC formula that considers unstable market circumstances. The new redefined WACC can be a valuable tool in business planning for companies from different fields. The companies in the energy sector are very interested in the topic of WACC, considering not only the complex nature of the investments made and the long-term nature of investment recovery but also the multiple risks that have an impact on their activity and that can be found in different economic, social, and geopolitical spheres. [ABSTRACT FROM AUTHOR]

The sizing of microgrids depends on the type of load and its operational hours. The significance of understanding the load operational characteristics in special purpose islanded microgrids is much needed for economic system sizing. The load operation of special-purpose microgrids often consumes high power for a short duration and remains idle most of the time, thus reducing the load factor. The inclusion of such loads in microgrid sizing causes huge capital costs making islanded microgrids an unfeasible solution. The islanded microgrid under study is an agricultural microgrid in a village having a small Crab Processing Plant (CPP) and a Domestic Sector (DS). The CPP constitutes the major power consumption. The community has a unique load consumption trend that is dependent on the highly uncertain parameter of availability of the crabs. Interestingly, crab availability is an independent parameter and cannot be accurately scheduled. The existing system sizing of the microgrid is performed based on the conventional methods that consider the CPP for full-day operation. However, the microgrid sources, especially the storage system may be reflected as oversized if the crab processing plants do not operate for several days due to the uncertain behavior of CPP causing enormous power wastage. In this paper, an integrated fixed and operational mode strategy for uncertain heavy loads is formulated. The proposed algorithm is based on the optimal sizing methodology aided by the load scheduling control strategy. The Particle Swarm Optimization technique is used for the optimal sizing integrated with the fuzzy logic controller to manage the available load. The membership functions are available excess power and the state of the charge of storage that defines the operational conditions for CPP. Based on input membership functions, the fuzzy controller decides on power dispatch in DS or CPP, keeping considerable SoC available for night hours. The simulation result shows that the time-dependent fuzzy controller approach manages to provide power to both sectors under optimal sizing while reducing the overall cost by 24% less than the existing microgrid. [ABSTRACT FROM AUTHOR]

The power-sharing possibility amongst microgrids (MGs) in networked microgrids (NMGs) offers multiple profits to the NMG by employing an applicable energy management system. An efficient energy management system can provide an adequate compromise in terms of the component sizing of NMGs through MG collaboration. This paper proposes a procedure to size the component for an isolated networked hybrid microgrid. The proposed design procedure relies on the optimum operation of individual MGs. The defined Reduced Factor (RF) identifies the possible size reduction for the dispatchable components, such as diesel generators and the energy storage system of each MG. The introduced RF is based on the operating reserve evaluation obtained from the optimal operation of individual MGs and the correlation between load profiles. Eventually, the simulation and practical results of a networked hybrid MG consisting of three MGs are presented to verify the proposed component sizing procedure. The practical results verify the theoretical expectations. The results show that NPC and capital costs are reduced up to 13% and 17%, respectively. [ABSTRACT FROM AUTHOR]

Due to the significance of environmental aspects, the modeling of hybrid systems should be performed with the lowest cost and environmental pollution. Therefore, an effective and optimum sizing method can ensure acceptable performance. This paper implements a "technique for order performance by similarity to the ideal solution" (TOPSIS) method combined with the "analytic hierarchy process (AHP)" method to size a standalone system based on techno-economic parameters. For this reason, a survey was conducted to collect local load data on Monpura Island, located in Bhola, Bangladesh. Visible and design faults of the existing PV/diesel mini-grid have also been identified. Five alternative hybrid configurations have been considered as to evaluate the best optimum system. Two economic and one environmental criterion was used to size the system. Two experts specialized in energy systems evaluated the criteria and proposed the suitable system. Battery, wind and PV capital cost multipliers have been considered as to perform sensitivity analysis. According to techno-economic analysis and expert opinion, PV/biogas/wind has been found to be the most appropriate system among these configurations. The system has a cost of electricity (COE) of 0.691 (USD/kWh) and emits only 4.43 kg of CO2 per year. The net present cost of the proposed system is 18% lower than the existing microgrid, and the model has lower emissions due to high renewable penetration. It was also found that integrating wind can significantly reduce battery capacity in the mini-grid. The proposed system consumes 34% less batteries than the existing system. Implementing this optimum system can result in greater benefit to the local people. [ABSTRACT FROM AUTHOR]

Several regulations and standards have been developed to reduce the carbon footprint of buildings, but these have failed to provide a clear pathway to a net zero future. Hence, we recently introduced the Active Building Code (ABCode). This provides guidance on reducing the environmental impact of the next generation of buildings, termed Active Buildings (ABs), through their synergy with the grid. This paper aims to illuminate the regulatory landscape, justify our initial proposal for the ABCode, and reveal opportunities and challenges to the popularisation of ABs. Twelve online focus group discussions were conducted, with thirty stakeholders in total, all selected on the basis of their expertise. A grounded theory approach identified five core themes in such discussions. These strongly overlap with what is incorporated in the ABCode, suggesting the code successfully captures issues important to experts. Stakeholders defined ABs as responsive buildings and proposed both energy and carbon are considered in their assessment. They hence aligned with the definition and evaluation framework proposed by the ABCode. Finally, stakeholders considered people's tendency to prioritise capital cost as the greatest challenge to the popularisation of ABs, and the increasing demand for healthy environments as its greatest opportunity. [ABSTRACT FROM AUTHOR]

The operation of natural gas grids requires electric-powered devices as data acquisition and control systems, surveillance and communication appliances, etc., often located in remote, unpopulated off-the-grid areas, where there is no personnel for surveillance, and maintenance costs are prohibitive. The literature on the power generating systems for these devices is limited to specific applications without a comparison between competing technologies, making their choice a difficult task for natural gas operators. This work presents a comprehensive up-to-date survey of market available technologies for remote power generation in the range of 20–1000 W for gas grid applications: thermoelectric generators, solid acid, direct methanol and solid oxide fuel cells, Stirling engines and microturbines. The work aims at sorting the technologies by techno-energetic, economic and environmental performance while providing specific technological characteristics and limitations. The results indicate well-defined ranges of power in which only some of the technologies are suitable and have very different efficiencies (3–30%). The capital cost of equal power technologies is similar (EUR 5000–30,000) and roughly linear with power (34.8Pel + EUR 6553), whereas operation costs (10–120 cEUR/kWh) and lifetime (0.5–20 yr) significantly depend on the technology. The indications of this review may constitute helpful guidelines to choose properly power generation systems for remote applications. [ABSTRACT FROM AUTHOR]

This article analyzed the cost of capital under risk conditions for thermoelectric plants in Brazil, applying the Capital Asset Pricing Model—CAPM and the Weighted Average Capital Cost—WACC. To estimate the local CAPM, we used information from the Electric Energy Index—IEE of publicly traded companies in the electricity sector in Brazil and for the global CAPM, we observed the companies associated with the Edison Electric Institute—EEI, listed on the New York Stock Exchange—NYSE and at the National Association of Securities Dealers Automated Quotations—NASDAQ—USA. The risk conditions for capital costs were represented by Monte Carlo simulation using, as a basis, the WACC of a fuel oil thermoelectric plant and the local and global CAPM. The main results show that the IEE and EEI companies obtained a positive average daily return. Due to the Brazil risk, under deterministic conditions, the local WACC (11.13% p.a.) was more attractive to investors when compared to the global WACC (10.32% p.a.) and the regulatory WACC of 10.55% p.a., established by the National Electric Energy Agency—ANEEL. The most risk-sensitive input variables were: unleveraged beta, net debt and equity. Under risk conditions observed by the market from the point of view of Brazilian companies, the chances of the WACC of the fuel oil thermoelectric plant being 11.1% p.a. was 68.30% and from a global perspective, the chance of WACC being 10.32% p.a. was 99.51%. It is concluded that the cost of capital under risk conditions provides a more realistic view of decision-making for privately held companies. [ABSTRACT FROM AUTHOR]

Sophorolipids (SLs) are microbial biosurfactants with an important role in industry and a continuously growing market. This research addresses the use of sustainable resources as feedstock for bioproducts. Winterization oil cake (WOC) and molasses are suitable substrates for SLs via solid-state fermentation (SSF). The model proposed herein was established for annually processing 750 t of WOC and comparing three support materials: wheat straw (WS), rice husk (RH), and coconut fiber (CF). Production capacity ranged 325–414 t of SLs per year. Unit Production Cost was 5.1, 5.7, and 6.9 USD/kg SL for WS, RH, and CF production models, respectively, and was slightly lower with other substrates. Financial parameters were CAPEX 6.7 MM USD and OPEX 1.9 MM USD/y, with a NPV, IRR and payback time of 6.4 MM USD, 31% and 3.2 y, respectively. SLs recovery from the solid matrix was the major contributor to operating costs, while fermentation equipment shaped capital costs. Results show that the physical properties (bulk density, WHC) of substrates and supports define process costs beyond substrate purchase costs and process yields in SSF systems. To our knowledge, this is the first attempt to model SLs production via SSF at full scale for the economic valuation of the SSF process. [ABSTRACT FROM AUTHOR]

Nowadays, several technologies for desalination processes are available and widely employed. However, they consume a considerable amount of energy and involve high capital and operating costs. Therefore, the techno-economic analysis of a system coupling different energy sources with the desalination processes is of value. The possibility of coupling a small gas turbine combined heat and power system (GT CHP) with hybrid desalination plants (HDPs) has been assessed in this study. The proposed gas turbine power generation system, based on a single-stage centrifugal compressor and an uncooled centripetal turbine, provides design simplicity and reasonable installation costs for the power generating plant. The hybrid desalination technique, based on the use of two different desalination technologies, i.e., Reverse Osmosis (RO) and a thermal desalination process, has been chosen to better exploit the electrical and thermal energy produced by the mini CHP plant. The proposed solution is numerically investigated from both thermodynamic and economic points of view, and the results of the thermodynamic analysis of the cycle are used as input for the evaluation of the amount of freshwater produced and of costs. The economic assessment of standalone desalination systems is also shown for the comparison with the hybrid solutions here proposed. Results show that the total cost of the water produced by MED + RO was less than the total cost of the water obtained by MSF + RO, and that the energy cost of MED + RO hybrid desalination system was about 15% less than that for stand-alone RO desalination technology. Thus, the MED + RO hybrid desalination system can be considered a promising solution for the coupling with the proposed mini GT CHP plant, which, due to the small size and cost, as well as the easy installation, can be easily applied in off-grid or remote areas. [ABSTRACT FROM AUTHOR]

Optimal dispatch is a major concern in the optimization of hybrid energy systems (HESs). Efficient and effective dispatch models that satisfy the load demand at the minimum net present cost (NPC) are crucial because of the high capital costs of renewable energy technologies. The dispatch algorithms native to hybrid optimization of multiple energy resources (HOMER) software, cycle-charging (CC) and load-following (LF), are powerful for modeling and optimizing HESs. In these control strategies, the decision to use fuel cell systems (FCs) or battery energy storage systems (BESs) at each time step is made based on the lowest cost choice. In addition, the simultaneous operation of a FC with a BES reduces the operating efficiency of the FC. These deficiencies can affect the optimal design of HESs. This study introduces a dispatch algorithm specifically designed to minimize the NPC by maximizing the usage of FCs over other components of HESs. The framework resolves the dispatch deficiencies of native HOMER dispatch algorithms. The MATLAB Version 2021a, Mathworks Inc., Natick, MA, USA Link feature in HOMER software was used to implement the proposed dispatch (PD) algorithm. The results show that the PD achieved cost savings of 4% compared to the CC and LF control dispatch strategies. Furthermore, FCs contributed approximately 23.7% of the total electricity production in the HES, which is more than that of CC (18.2%) and LF (18.6%). The developed model can be beneficial to engineers and stakeholders when optimizing HESs to achieve the minimum NPC and efficient energy management. [ABSTRACT FROM AUTHOR]

Anaerobic digestion (AD) plants enable renewable fuel, heat, and electricity production, with their efficiency and capital cost strongly dependent on their installed capacity. In this work, the technical and economic feasibility of different scale AD combined heat and power (CHP) plants was analyzed. Process configurations involving the use of waste produced in different farms as feedstock for a centralized AD plant were assessed too. The results show that the levelized cost of electricity are lower for large-scale plants due to the use of more efficient conversion devices and their lower capital cost per unit of electricity produced. The levelized cost of electricity was estimated to be 4.3 p/kWhe for AD plants processing the waste of 125 dairy cow sized herds compared to 1.9 p/kWhe for AD plants processing waste of 1000 dairy cow sized herds. The techno-economic feasibility of the installation of CO2 capture units in centralized AD-CHP plants was also undertaken. The conducted research demonstrated that negative CO2 emission AD power generation plants could be economically viable with currently paid feed-in tariffs in the UK. [ABSTRACT FROM AUTHOR]

One of the main challenges for widespread penetration of plug-in hybrid electric vehicles (PHEVs) is their impact on the electricity grid. The energy sector must anticipate and prepare for this extra demand and implement long-term planning for electricity production. In this paper, the additional electricity demand on the Ontario electricity grid from charging PHEVs is incorporated into an electricity production planning model. A case study pertaining to Ontario energy planning is considered to optimize the value of the cost of the electricity over sixteen years (2014–2030). The objective function consists of the fuel costs, fixed and variable operating and maintenance costs, capital costs for new power plants, and the retrofit costs of existing power plants. Five different case studies are performed with different PHEVs penetration rates, types of new power plants, and CO2 emission constraints. Among all the cases studied, the one requiring the most new capacity, (~8748 MW), is assuming the base case with 6% reduction in CO2 in year 2018 and high PHEV penetration. The next highest one is the base case, plus considering doubled NG prices, PHEV medium penetration rate and no CO2 emissions reduction target with an increase of 34.78% in the total installed capacity in 2030. Furthermore, optimization results indicate that by not utilizing coal power stations the CO2 emissions are the lowest: ~500 tonnes compared to ~900 tonnes when coal is permitted. [ABSTRACT FROM AUTHOR]

In this study, we used the thermoeconomic theory to evaluate the impact of residue cost formation on the cost of electricity generated from natural gas burned in a gas turbine that applied sequential combustion; we also analyzed the impact of the combustion process on the additional fuel consumption to compensate for a malfunction component. We used the Alstom GT24 gas turbine, which applied sequential combustion and generated 235 MW of power. Thermoeconomic analysis indicated that the exergy cost of power generation was 626.33 MW (30.42% corresponded to irreversibility costs, and 29.22% and 2.84% corresponded to the formation costs of physical and chemical residues, respectively). The exergoeconomic production cost of gas turbine was 10,098.71 USD/h, 34.76% from external resources and 65.24% from capital and operating costs. Thermoeconomic diagnosis revealed that a compressor deterioration (of 1-% drop in the isentropic efficiency) resulted in an additional fuel consumption of 4.05 MW to compensate for an increase in irreversibilities (1.97 MW) and residues (2.08 MW); the compressor generated the highest cost (49.9% of additional requirement). Thus, our study can identify the origin of anomalies in a gas-turbine system and explain their effects on the rest of the components. [ABSTRACT FROM AUTHOR]

The global tidal energy resource for electricity generation is small, and converting tidal kinetic energy to electricity is expensive compared to solar-photovoltaic or land-based wind turbine generators. However, as the renewable energy content in electricity supplies grows, the need to stabilise these supplies increases. This paper describes tidal energy's potential to reduce intermittency and variability in electricity supplied from solar and wind power farms while lowering the capital expenditure needed to improve dispatchability. The paper provides a model and hypothetical case studies to demonstrate how sharing energy storage between tidal stream power generators and wind or solar power generators can mitigate the level, frequency, and duration of power loss from wind or solar PV farms. The improvements in dispatchability use tidal energy's innate regularity and take account of tidal asymmetry and extended duration low-velocity neap tides. The case studies are based on a national assessment of Australian tidal energy resources carried out from 2018 to 2021. [ABSTRACT FROM AUTHOR]

Hydropower as stable power installations play an important role among renewable energy sources. Yet, their share in renewable energy is small. Currently, it is only 10% of energy from renewable energy sources (RES), compared to 27% in 2010. Therefore, the aim of this paper is to assess the RES support schemes in Poland related to hydropower, such as green certificates, auctions and FIT, with the use of the Levelized Cost of Electricity (LCOE) analysis in order to determine which support scheme is best incentivizing hydropower development. The evolution of the hydropower support scheme in Poland is presented. The total LCOE and possible revenues from support systems for various segments of hydropower installations are graphically analyzed for two analysis periods (15 and 50 years) and for two discount rates (7% and 11.4%). The analysis shows the great importance of the support schemes in the profitability of the hydropower plants investments. The LCOE graphical analysis proves to be suitable for showing sensitivity analysis of capital and operating costs of various sizes of hydropower plants. The analysis shows that the LCOE in micro-power plants is usually higher than the support and revenues available in the green certificates or auctions or FIT schemes in Poland. [ABSTRACT FROM AUTHOR]

The main objective of this article is to test the relationship between the intensity of CO2 emissions and company's cost of debt capital. This study fills a gap in the financial literature on this compound by examining a sample of 225 large nonfinancial enterprises operating in 15 EU countries in the years 2018–2021. The fractional logit regression controlling for company's characteristics (assets, profitability, liquidity and leverage) was used. The results show that by reducing the intensity of CO2 emissions, a company can reduce the cost of debt. This relationship was confirmed for three measures of intensity, i.e., CO2 emissions in relation to revenues, assets and number of employees. Markets and financial institutions impose an additional risk premium in relation to companies operating in an industry considered to be comprised of strong CO2 emitters. The use of the latest data for a wide sample of European enterprises provides an up-to-date assessment of the analyzed issues and the results can be used by enterprises and public authorities when analyzing the benefits of implementing a technology that reduces CO2 emissions. [ABSTRACT FROM AUTHOR]

Biological biogas upgrading with H2 derived from excess renewable electricity was modeled and simulated in PROII® (AVEVA Group plc, Cambridge, UK). An economic analysis was performed for a biogas plant processing 100,000 tons of biomass (substrate) per year. The biogas and biomethane production simulation results were validated with laboratory experimental data, as well as full-scale data obtained from biogas plants. A biomethane production cost of 0.47 €/Nm3 was calculated, while the minimum biomethane selling price for NPV = 0 was equal to 0.66 €/Nm3, considering a H2 price of 1.0 €/kg. The feasibility analysis indicated that the H2-related costs were the major contributor to the capital and operation costs due to high expenses associated with the in-situ H2 storage facility and the purchasing of H2, respectively. Compared to conventional upgrading methods, biological biogas upgrading has a higher capital and production cost, which can be reduced by increasing the plant capacity. The sensitivity analysis showed that the profitability is very sensitive to biomethane prices, capital investment, and the H2 price. [ABSTRACT FROM AUTHOR]

The concept of risk is well known in the energy sector. It is normally recognized when it comes to price and cost forecasting, annual production calculation, or evaluating project lifetime. Nevertheless, it should be pointed out that the quantitative evaluation of risk is usually difficult. The discount rate is the only parameter reflecting risk in the discounted cash flow analysis. Therefore, knowledge of the discount rate along with the major components affecting its level is of fundamental significance for making investment decisions, capital budgeting, and project management. By referring to the standard coal-fired power generation projects the authors of the paper tackle the analysis of the composition of discount rate for onshore wind farm technologies in the Polish conditions. The study was carried out on the basis of a typical (hypothetical) onshore wind farm project assessed at the feasibility stage. To enable comparisons and discussions, it was assumed that the best reference point for such purposes is the real risk-adjusted discount rate, RADR, after-tax, in all equity evaluations (the 'bare bones' assumption); that is because such a rate reflects the inherent characteristics of the project risk. The study methodology involves the a priori application of the discount rate level and subsequently—in an analytical way—calculation of its individual components. The starting point for the analysis of the RADR's composition was the definition of risk, understood as the product of uncertainty and consequences. Then, the risk factors were adopted and level of uncertainty assessed. Subsequently, using the classical sensitivity analysis of IRR, the consequences (as slopes of sensitivity lines) were calculated. Consequently, risk portions in percentage forms were received. Eventually, relative risks and risk components within cost of equity were assessed. Apart from the characteristics of the discount rate at the feasibility stage, in the discussion section the study was supplemented with an analogous analysis of the project's cost of equity at the operating stage. [ABSTRACT FROM AUTHOR]

An inventive method was applied to determine the minimum major radius, R0, and the optimum build of a tokamak fusion reactor that simultaneously meets all physics, engineering, and neutronics constraints. With a simple cost model, tokamak systems analyses were carried out over ranges of system parameters to find an optimum build of a tokamak fusion reactor at minimum cost. The impact of a wide range of physics parameters and advanced engineering elements on costs were also addressed. When a central solenoid was used to ramp up a plasma current, design solutions with a cost of electricity (COE) between 109 and 140 mills/kWh, direct capital cost between 5000 and 6000 M/USD, and net electric power, Pe between 1000 and 1600 MW could be found with a minimum R0 between 6.0 and 7.0 m, and fusion power, Pfusion between 2000 and 2800 MW. When the plasma current was driven by a non-inductive external system, the system size and costs could be reduced further; a COE between 98 and 130 mills/kWh, direct capital cost between 4000 and 5000 M$, and Pe between 1000 and 1420 MW could be found with a minimum R0 between 5.1 and 6.7 m, and Pfusion between 2000 and 2650 MW. [ABSTRACT FROM AUTHOR]

During the design of extra-high-voltage transmission lines, studies of the influence of asymmetry due to the phase difference of the parameters on its processes and the electrical network were performed. To compensate for this source of asymmetry for transmission lines longer than 100 km, a relatively simple technical means was proposed and implemented—phase transposition (change of the mutual location of phase wires in space). However, at the same time transposition causes additional capital costs in construction and reduces reliability during operation, so when designing a specific transmission line, extra-high-voltage is desirable to evaluate the effectiveness of the use of this measure in the real electricity network. Thus, under certain conditions, even for a transmission line 600 km in length, it was possible to perform either an incomplete transposition cycle, or abandon this measure altogether. [ABSTRACT FROM AUTHOR]

The design and development of wind turbines in low-wind-speed areas involves several technical and financial challenges related to maximizing conversion efficiency and minimizing cost. Unfortunately, much of the African continent is dominated by low-wind-speed resources. In this study, a multi-parameter optimization method is used to explore the design of a novel Ferris wheel wind turbine (FWT) technology, which has an 800-kW generation capability. We used the tip speed ratio, lift-to-drag ratio and power coefficient to determine the optimal efficiency by varying the number of blades and rim diameters. The capital cost estimates, as affected by rim diameter and the number of blades, are presented. This paper studies FWTs at their rated wind speeds because wind turbines have their maximum performance at the rated wind speeds, and this allows one to observe the effects of changing the rim diameter and the number of blades without the need to consider the location of the turbine. The results show that reducing the number of spokes by half (from 64 to 32) on the four rim diameters studied decreases the efficiency by less than 0.19%, while reducing the acquisition cost by 42%, installation cost by 42% and mass by 28%. Reducing the number of spokes to a quarter (i.e., from 32 to 16) decreases the efficiency by less than 0.31%, reduces the acquisition and installation costs by 36% and 35.5%, respectively, and the mass by 19.2%, of the four rim diameters studied. The reduction of the number of blades has a significant effect on the efficiency and capital cost with varying rim diameters. This paper shows the potential for Ferris-wheel-based wind turbines for low-wind-speed conditions, such as those that prevail in parts of Africa. [ABSTRACT FROM AUTHOR]

Fuel cell technologies have several applications in stationary power production, such as units for primary power generation, grid stabilization, systems adopted to generate backup power, and combined-heat-and-power configurations (CHP). The main sectors where stationary fuel cells have been employed are (a) micro-CHP, (b) large stationary applications, (c) UPS, and IPS. The fuel cell size for stationary applications is strongly related to the power needed from the load. Since this sector ranges from simple backup systems to large facilities, the stationary fuel cell market includes few kWs and less (micro-generation) to larger sizes of MWs. The design parameters for the stationary fuel cell system differ for fuel cell technology (PEM, AFC, PAFC, MCFC, and SOFC), as well as the fuel type and supply. This paper aims to present a comprehensive review of two main trends of research on fuel-cell-based poly-generation systems: tracking the market trends and performance analysis. In deeper detail, the present review will list a potential breakdown of the current costs of PEM/SOFC production for building applications over a range of production scales and at representative specifications, as well as broken down by component/material. Inherent to the technical performance, a concise estimation of FC system durability, efficiency, production, maintenance, and capital cost will be presented. [ABSTRACT FROM AUTHOR]

The growth in renewable energy integration over the past few years, primarily fueled by the drop in capital cost, has revealed the requirement for more sustainable methods of integration. This paper presents a collocated hybrid plant consisting of solar photovoltaic (PV) and Ternary pumped-storage hydro (TPSH) and designs controls that integrate the PV plant such that the behavior and the controllability of the hybrid plant are similar to those of a conventional plant within operational constraints. The PV array control and hybrid plant control implement a neural–network-based framework to coordinate the response, de-loading, and curtailment of multiple arrays with the response of the TPSH. With the help of the designed controls, a symbiotic relationship is developed between the two energy resources, where the PV compensates for the TPSH nonlinearities and provides required speed of response, while the TPSH firms the PV system and allows the PV to be integrated using its existing infrastructure. Simulations demonstrate that the designed controls enable the PV system to track references, while the TPSH's firming and shifting transforms the PV system into a base load plant for most of the day and extends its hours of operation. [ABSTRACT FROM AUTHOR]

Energy storage devices are collocated with conventional solar photovoltaic (PV) systems to tackle the intermittency of solar irradiance and maintain the power quality of supplied energy. The energy storage system usually has its own conversion devices that may incur an extra capital cost of installation. This paper proposes an integrated and cost-effective photovoltaic-supercapacitor (PVSC) system in which the energy storage functionality of the supercapacitor (SC) is merged into the PV array where the power flow bidirectionally takes place to maintain the system stability under grid disturbances during the daytime, nighttime, and cloudy weather. A nonlinear mathematical model (NMM) was developed to conduct the stability analyses and to design the controller parameters, which facilitates a faster and more accurate numerical analysis compared to existing average models. The effectiveness of the proposed system was evaluated by simulation analysis and compared to that of the basic PV and a conventional SC system in which full energy storage is connected in parallel with the PV. The results demonstrate that the proposed PVSC system is effective in improving the dynamic performance of the connected power grid system. In addition, the proposed PVSC system fulfills the functionality of the conventional SC with merged conversion devices; that is, the performance of the proposed PVSC system is comparable to the conventional SC system. [ABSTRACT FROM AUTHOR]

Economic cost is decisive for the development of different power generation. Life cycle cost (LCC) is a useful tool in calculating the cost at all life stages of electricity generation. This study improves the levelized cost of electricity (LCOE) model as the LCC calculation methods from three aspects, including considering the quantification of external cost, expanding the compositions of internal cost, and discounting power generation. The improved LCOE model is applied to three representative kinds of power generation, namely, coal-fired, biomass, and wind power in China, in the base year 2015. The external cost is quantified based on the ReCiPe model and an economic value conversion factor system. Results show that the internal cost of coal-fired, biomass, and wind power are 0.049, 0.098, and 0.081 USD/kWh, separately. With the quantification of external cost, the LCCs of the three are 0.275, 0.249, and 0.081 USD/kWh, respectively. Sensitivity analysis is conducted on the discount rate and five cost factors, namely, the capital cost, raw material cost, operational and maintenance cost (O&M cost), other annual costs, and external costs. The results provide a quantitative reference for decision makings of electricity production and consumption. [ABSTRACT FROM AUTHOR]

Gas-fired heat pumps are a potential replacement for condensing boilers, utilizing fossil-fuel resources more efficiently and reducing the amount of biogas or hydrogen required in sustainable gas grids. However, their adoption has been limited due to their large size and high capital cost, resulting in long payback times. For adsorption-based heat pumps, the major development challenge is to maximize the rate of heat transfer to the adsorbent, whilst minimizing the thermal mass. This work develops a modular finned-tube carbon–ammonia adsorption generator that incorporates the adsorbent in highly compacted 3-mm layers between aluminum fins. Manufacturing techniques that are amenable to low cost and high-volume production were developed. The module was tested using the large temperature jump (LTJ) method and achieved a time constant for adsorption and desorption of 50 s. The computational model predicted that if incorporated into two adsorption generators of 6 L volume each, they could be used to construct a gas-fired heat pump with a 10 kW heat output and a gas utilization efficiency (GUE, the ratio of useful heat output to higher calorific value of gas used) of 1.2. [ABSTRACT FROM AUTHOR]

This study determines the relationship between the increase in size of dry bulk carriers and container ships and the changes in sustainable shipping performance. It measures the elasticities of shipping costs for bulk carriers and container ships. Using regression, it derives the functions of the daily and unit costs of shipping with respect to the size of dry bulk carriers and container ships. The estimated daily and unit cost elasticities and cost models reveal significant but diversified impacts of vessel size on dry bulk and container shipping cost and its components, other operating capital, and fuel costs. Findings: Dry bulk carriers and containership size mean elasticities of daily operating costs estimates respectively: total operating costs 0.291 and 0.552, other operating cost (labor cost included) 0.238 and 0.328, capital costs 0.329 and 0.765, fuel costs 0.289 and 0.462; dry bulker and container ship unit shipping mean elasticity respectively: full operating costs (−0.751) and (−0.553), other operating cost (−0.804) and (−0.782), capital costs (−0.713) and (−0.399), fuel costs (–0.757) and (−0.702). This research provides an insight into the impact of technology and the way the services are provided (irregular versus regular) on shipping cost and energy savings. The cost models can be used for estimating the savings in shipping costs resulting from handling larger vessels in seaports. [ABSTRACT FROM AUTHOR]

This work analyses and discusses data on thermochemical plants in Southern Italy that are fed with solid biomass. The analysis takes into account the biomass availability and potential together with the cost-benefit analysis using technology development and economic indicators (LCOE). A total of 63,762 units have been categorised according to the employed technology and produced energy: power plants for electricity production or cogeneration plants for combined heat and electricity production (53 plants) and thermal units for heat production (63,709 units). The eight regions of the area have noteworthy differences. In terms of electricity generated from solid biomass Calabria is by far the largest producer, followed by Apulia. Sicily, Sardinia and Molise provide lower amounts while Abruzzo, Basilicata and Campania generate almost negligible amounts. Regarding thermal production, Campania and Calabria are the largest producers, but Basilicata, Molise and Abruzzo generate the highest amount per capita. The area is far from fully exploiting its biomass potential, and there are also no district heating grids. Bioenergy can be remarkably competitive, provided that capital costs are relatively low and low-cost biomass is available, as it is the case of Italy. New applications and markets for sub-products (i.e., char, ash) would help in lowering the still not competitive economic indicators (LCOE). [ABSTRACT FROM AUTHOR]

The European Union Green Deal aims at curbing greenhouse gas emissions and introducing clean energy production. But to achieve energy efficiency, the opportunity cost of different energies must be assessed. In this article, two different energy self-sufficient systems for wastewater treatment are compared. On the one hand, high-rate algal ponds system (HRAP) is considered; on the other hand, a conventional activated sludge system (AS) which uses photovoltaic power (PV) is studied. The paper offers a viability analysis of both systems based on the capacity to satisfy their energetic consumption. This viability analysis, along with the opportunity cost study, will be used in the article to compare these two projects devoted to the treatment of wastewater. In order to assess viability, the probability of not achieving the energy consumption threshold at least one day is studied. The results point that the AS+PV system self-sufficiency is achieved with much lesser land requirements than the HRAP system (for the former, less than 6500 m2, for the latter 40,000 m2). However, the important AS capital cost makes still the HRAP system more economic, although storage provides a great advantage for using the AS+PV in locations where a lot of irradiance is available. [ABSTRACT FROM AUTHOR]

The incorporation of phase change materials (PCM) in buildings has the potential to enhance the thermal efficiency of buildings, reduce energy cost, shift peak load, and eventually reduce air pollution and mitigate global warming. However, the initial capital cost of PCM is still high, and thus the establishment of a control strategy has become essential to optimize its use in buildings in an effort to lower investment costs. In this paper, an extensive review has been made with regard to various control strategies applied to PCM-enhanced buildings, such as ON/OFF control, conventional control methods (classical control, optimal, adaptive, and predictive control) and intelligent controls. The advantages and disadvantages of each control strategy are evaluated. The paper further discusses the opportunities and challenges associated with the design of PCM-enhanced buildings in combination with control strategies. [ABSTRACT FROM AUTHOR]

This paper aims to identify the costs of capital in a group of companies from the energy sector by including an investor and market risk approach. The study also concerns the company's Weighted Average Cost of Capital (WACC) cost intra-industry analysis related to sector characteristics such as total assets, revenues, market capitalization, and companies' age. In order to assess the intergroup relationships, basic correlation relationships were compared and a nonparametric test of variance was performed. The period under study covered the years 2015–2019. The conducted research evaluates groups of companies that dedicated their activity to a particular energy intra-industry division under numerous regulations in Europe. The study contributes to assessing the level of risk among energy listed companies in European capital markets based on capital structure valuation. The study results underline the role of the cost of equity financing, which was twice as high as the cost of debt. The highest WACC was related to the Beta indicator that also expressed the political and regulatory risk over the investigated period. Across debt cost analysis, the role of effective tax rate decreased the level of WACC. The highest level of WACC was noticed among uranium and integrated oil and gas companies. The study contributes to information asymmetry theory related to the cost of capital assumptions. [ABSTRACT FROM AUTHOR]

Steelmaking is responsible for approximately one third of total industrial carbon dioxide (CO2) emissions. Hydrogen (H2) direct reduction (H-DR) may be a feasible route towards the decarbonization of primary steelmaking if H2 is produced via electrolysis using fossil-free electricity. However, electrolysis is an electricity-intensive process. Therefore, it is preferable that H2 is predominantly produced during times of low electricity prices, which is enabled by the storage of H2. This work compares the integration of H2 storage in four liquid carriers, methanol (MeOH), formic acid (FA), ammonia (NH3) and perhydro-dibenzyltoluene (H18-DBT), in H-DR processes. In contrast to conventional H2 storage methods, these carriers allow for H2 storage in liquid form at moderate overpressures, reducing the storage capacity cost. The main downside to liquid H2 carriers is that thermochemical processes are necessary for both the storage and release processes, often with significant investment and operational costs. The carriers are compared using thermodynamic and economic data to estimate operational and capital costs in the H-DR context considering process integration options. It is concluded that the use of MeOH is promising compared to the other considered carriers. For large storage volumes, MeOH-based H2 storage may also be an attractive option to the underground storage of compressed H2. The other considered liquid H2 carriers suffer from large thermodynamic barriers for hydrogenation (FA) or dehydrogenation (NH3, H18-DBT) and higher investment costs. However, for the use of MeOH in an H-DR process to be practically feasible, questions regarding process flexibility and the optimal sourcing of CO2 and heat must be answered. [ABSTRACT FROM AUTHOR]