Techno-economic Benefits Research Articles

Technoeconomic analysis of thermoelectric power plant condensers with nonwetting surfaces

This paper investigates the dynamic performance and economic benefits of using nonwetting tube surfaces fabricated by electrodeposition process in thermoelectric power plant condensers. Nonwetting surfaces enhance performance by reducing fouling resistance and promoting dropwise condensation of steam on the shell side. Using a thermal resistance network of a shell and tube condenser, detailed parametric studies are presented to investigate the effects of design parameters and operating parameters on the annual condenser performance and its impact on the net electric energy output of a representative 550 MW coal-fired power plant. A cost model is presented to evaluate the technoeconomic benefits of the enhanced condenser design in a unified manner, in terms of a new levelized cost of condenser (LCOC) metric. The model is coupled with a numerical optimization method to identify optimal nonwetting condenser tube designs that minimize LCOC. The results show optimal cooling water flow velocity of 2.5 m/s and tube diameter of 0.032 m (0.025 m) for nonwetting (plain) condenser tube surfaces that exhibit dropwise (filmwise) condensation. Condensers with nonwetting surfaces are shown to reduce LCOC by a factor of 2.5 and 1.7, respectively, compared to plain titanium and aluminum-brass tubes.

Techno-economic benefits deriving from optimal scheduling of a Virtual Power Plant: Pumped hydro combined with wind farms

Wind and solar are renewable sources characterized by a great potential but a variable and unpredictable nature. Characteristics that provoke mismatch between power supply and demand which in turns are the source of network control issues. Problems manageable with the installation of large-scale energy storage like Pumped Hydro Energy Storage (PHES). To this purpose, the paper presents a techno-economic analysis for assessing the benefits deriving from the hybridization of a seawater PHES (sPHES) plant with an in-operation wind farm. Plants work as a Virtual Power Plant (VPP) instead of two separate unit. The hybridization aims to avoid the unbalances of the wind farm, having negative impact on both the grid and the wind farm owner itself. The unbalances cause unpredictable deviations from the predicted production and, hence, power production fluctuations faced by the grid with curtailments and/or calls in operation of fossil-fuelled power plants. A VPP techno-economic optimization on a daily bases is performed using the ASD-PSO algorithm while the optimization aim is the revenue maximization. Results show that a VPP composed by a sPHES and a wind farm and with a single owner, is able to manage the wind farm production, improving the revenue of 6.8% compared to plants acting separately on the market. The VPP approach is also convenient in the case of a joint venture between the plants owners. But, in this case, the revenue is increased only of 0.4% compared to plants working separately. Finally, results also highlight that, in the Italian electricity market, a sPHES plant alone is not able to generate sufficient revenue to guarantee a reasonable payback time while coupling it with a wind farm increases incomes and working days and avoid cost and grid issues in managing the unpredictable wind farm production.

Analysis of Influencing Factors of Modification Potential of Abandoned Coal Mine Into Pumped Storage Power Station

Abstract By modifying underground spaces of abandoned coal mines into underground pumped storage power stations, it can realize the efficient and reasonable utilization of underground space and, at the same time, meet the increasing demand for energy storage facilities of the grid, bringing social, economic, and environmental benefits. Previous research in this area has been limited to the stage of conceptual discussion, and there is no scientific evaluation method for the modification and utilization potential of abandoned coal mine spaces. Establishing a scientific evaluation indicator system forms the basis for evaluating the underground space development and utilization capacity of abandoned mines. Based on the principle of pumped energy storage and the characteristics of coal mine roadway conditions, this paper utilized an analytical hierarchy process (AHP) to evaluate the main influencing factors, including elevation difference between the upper and lower reservoirs, reservoir capacity, roadway surrounding rock stability, and roadway permeability. It analyzed the modification potential of underground spaces and then verified the development potential of the underground spaces of abandoned mines by a statistic model. The study found that the elevation difference between the upper and lower reservoirs is the most influential indicator; second, the capacity of the upper and lower reservoirs is also an important evaluation indicator. The research methods and conclusions will provide useful tools and decision-making basis for analyzing the feasibility and techno-economic benefit of modifying the underground spaces of abandoned coal mines into pumped storage power stations.

One-step synthesis of molten salt nanofluid for thermal energy storage application – a comprehensive analysis on thermophysical property, corrosion behavior, and economic benefit

Concentrating solar power (CSP) plants have been widely commercialized for generating electricity from solar energy. Thermal energy storage (TES) systems have been deployed as a key component in CSP plants for resolving the supply-demand gap during daily operation. Nowadays, molten salts are used as both the primary heat transfer fluid (HTF) and as TES medium in many CSP plants. However, molten salts suffer from poor thermo-physical properties, e.g., specific heat capacity is typically less than 2 J/(g•K). In addition, the practical operational performance of CSP plants running on molten salt is limited by the chemical compatibility between the heat transfer fluid and the container. Many efforts have been devoted to developing molten salt material with enhanced thermal properties and reduced corrosivity. As a typical example, doping molten salts with minute quantities of nanoparticles has shown potential as a simple approach for enhancing the thermo-physical property values and mitigating corrosion due to formation of passivation on metal surface from naturally deposited nanoparticles. Nevertheless, mixing nanoparticles in solvents is not cost-effective for industrial applications and often results in agglomeration and precipitation issue. In this study, the feasibility of using molten salt nanofluid as the TES medium has been examined comprehensively based on its thermophysical property, corrosion behavior, and the economic value. Specifically, the specific heat capacity of the solar salt (NaNO3-KNO3 eutectic)-based nanofluid prepared from both two-step and one-step methods were measured at elevated temperatures (~500°C). In addition, the corrosion behavior of SS304 in molten salt nanofluids is investigated experimentally at 565 °C for 432 hours interval. Finally, the techno-economic benefit is assessed based on the energy storage capacity and material costs. The results from the study demonstrated that the one-step synthesis protocol for nanofluids involving generation of nanoparticles in-situ from cheap additives is a viable and cost-effective approach in industrial applications (e.g., CSP) for enhancing the energy storage capacity and power rating as well as for extending the life-cycle of equipment (e.g., heat exchangers).

Techno-economic design of energy systems for airport electrification: A hydrogen-solar-storage integrated microgrid solution

Can aviation really become less polluting? The electrification of airport energy system as a micro-grid is a promising solution to achieve zero emission airport operation, however such electrification approach presents the engineering challenge of integrating new energy resources, such as hydrogen supply and solar energy as attractive options to decarbonize the present system. This paper explores the techno-economic benefits of integrating hydrogen supply, electric auxiliary power unit (APU) of aircraft, electric vehicles, photovoltaic energy (PV), and battery storage system into electrified airport energy system. The hydrogen fuel cell generation provides great flexibility to supply aircraft at remote stands, and reduces the carbon emissions caused by traditional fuel-powered APU. A mixed integer linear programming optimization method based on life cycle theory is developed for capacity sizing of hydrogen energy system, PV and battery storage, with optimization objective of minimizing the total economic costs as well as considering environmental benefits of the proposed airport microgrid system. Case studies are conducted by five different energy integration scenarios with techno-economic and environmental assessments to quantify the benefits of integrating hydrogen and renewable energy into airport. Compared with the benchmark scenarios, the integration of hydrogen energy system reduced the total annual costs and carbon emissions of airport energy system by 41.6% and 67.29%, respectively. Finally, sensitivity analysis of key system parameters such as solar irradiance, grid emission factor, elctricity price, carbon tax, unit investment cost of hydrogen energy system have been investigated to inform the design of hydrogen-solar-storage integrated energy system for future airport electrification.

Stochastic Optimal Planning of Distribution System Considering Integrated Photovoltaic-Based DG and DSTATCOM Under Uncertainties of Loads and Solar Irradiance

Optimal planning of integration the Photovoltage Distributed Generation (PV-DG) and DSTATCOM is a crucial task due to the stochastic variations of PV output power and the load demand which are related to solar irradiance variations and the activities of the customers, respectively. In this article, the optimal planning problem of the PV-DG and DSTATCOM system is solved. The proposed model considers the uncertainties of the solar irradiance and the load demand for a multi-objective function, including the cost reduction, the voltage profile, and stability index improvement. Modified Ant Lion Optimizer (MALO) is proposed to enhance the basic ALO searching ability using two strategies. The first strategy is based on Levy Flight Distribution (LFD) to strengthen the exploration of the algorithm and avoid the premature of the basic ALO. In contrast, the second strategy is based on updating the solutions in a spiral orientation to improve the exploitation of the algorithm. The IEEE 69-bus and 118-bus radial distribution systems are used to demonstrate the effectiveness of the proposed method, and the yielded simulations are compared with the basic ALO and other well-known optimization techniques for power loss minimization under deterministic conditions. The simulation results demonstrate that the techno-economic benefits can be increased considerably by optimal inclusion of two PV-DGs and DSTATCOMs compared with a single system.

A metaphor-less based AI technique for optimal deployment of DG and DSTATCOM considering reconfiguration in the RDS for Techno-Economic benefits

The advent of distributed energy resources is undoubtedly transforming the nature of the electric power system. The crisis of conventional energy sources and their environmental effects resulted in the integration of Distributed Generators (DGs) into the distribution system. Simultaneous application of optimum network reconfiguration, DGs, and Distribution Static Compensator (DSTATCOM) unit’s placement in the Radial Distribution Systems (RDS) comes with a raft of technical, economic, and environmental benefits. Benefits include improved power quality, reliability, stability, mitigation of power losses, and voltage profile improvement. In this paper, the combinational process of optimal deployment of DGs and DSTATCOM units in RDS with suitable network reconfiguration to achieve positive benefits has been analyzed. A recent metaphor-less based Artificial Intelligence (AI) technique named the Rao-1 method is employed to overcome this combinational nonlinear optimization problem. The objective functions are to mitigate the power losses, enhance the voltage profile, and voltage stability index of the RDS considering the net economic cost-benefit to the distribution utility. The simulation study of this pragmatic approach problem is carried out on IEEE 33-bus RDS. The comparison of the results obtained by the Rao-1 method with other existing meta-heuristic optimization methods has been made to show its efficacy.

Modeling Economic Sharing of Joint Assets in Community Energy Projects Under LV Network Constraints

The trend of decentralization of energy services has given rise to community energy systems. These energy communities aim to maximize the self-consumption of local renewable energy generated and stored in assets that are typically connected to low-voltage (LV) distribution networks. Energy community schemes often involve jointly owned assets such as community-owned solar photo-voltaic panels (PVs), wind turbines and/or shared battery storage. This raises the question of how these assets should be controlled in real-time, and how the energy outputs from these jointly owned assets should be shared fairly among heterogeneous community members. Crucially, such real-time control and fair sharing of energy must also consider the technical constraints of the community, such as the local LV network characteristics, voltage limits and power ratings of electric cables and transformers. In this paper, we design and analyze a heuristic-based battery control algorithm that considers the influence of battery life degradation, and the resultant increase in local renewable energy consumption within local operating constraints of the LV network. We provide a model that first studies the techno-economic benefits of community-owned versus individually-owned energy assets considering the network/grid constraints. Then, using the methodology and principles from cooperative game theory, we propose a redistribution model for benefits in a community based on the marginal contribution of each household. The results from our study demonstrate that the redistribution mechanism is fairer and computationally tractable compared to the existing state-of-the-art methods. Thus, our methodology is more scalable with respect to modeling the economic sharing of joint assets in community energy systems.

The Techno-Economic Benefit of Sorption Enhancement: Evaluation of Sorption-Enhanced Dimethyl Ether Synthesis for CO2 Utilization

Dimethyl ether (DME) is an important platform chemical and fuel that can be synthesized from CO2 and H2 directly. In particular, sorption-enhanced DME synthesis (SEDMES) is a novel process that uses the in situ removal of H2O with an adsorbent to ensure high conversion efficiency in a single unit operation. The in situ removal of steam has been shown to enhance catalyst lifetime and boost process efficiency. In addition, the hydrogen may be supplied through water electrolysis using renewable energy, making it a promising example of the (indirect) power-to-X technology. Recently, major advances have been made in SEDMES, both experimentally and in terms of modeling and cycle design. The current work presents a techno-economic evaluation of SEDMES using H2 produced by a PEM electrolyzer. A conceptual process design has been made for the conversion of CO2 and green H2 to DME, including the purification section to meet ISO fuel standards. By means of a previously developed dynamic cycle model for the SEDMES reactors, a DME yield per pass of 72.4 % and a carbon selectivity of 84.7% were achieved for the studied process design after optimization of the recycle streams. The production costs for DME by the power-to-X technology SEDMES process at 23 kt/year scale are determined at ∼€1.3 per kg. These costs are higher than the current market price but lower than the cost of conventional DME synthesis from CO2. Factors with the highest impact on the business cases are the electricity and CO2 cost price as well as the CAPEX of the electrolyzer, which is considered an important component for technology development. Furthermore, as the H2 cost constitutes the largest part of the DME production cost, SEDMES is demonstrated to be a powerful technology for efficient conversion of green H2 into DME.

Optimal integration of distributed generation resources in active distribution networks for techno-economic benefits

In recent years, modern electricity utilities face great challenges regarding the deregulated energy markets, transition toward sustainable smart grids and the increased load demand. These challenges are a part of the reasons that have paved the way toward the rapid progress of spreading the different Distributed Generation (DG) technologies into the modern Distribution Networks (DNs). DGs integration into DNs can be employed as a key solution for tackling the problems, facing the distribution systems, and verifying more technical and economic benefits while considering the systems’ uncertainties and the operational policies of the distribution utilities. This paper introduces the application of Modified Sine Cosine Algorithm (MSCA) for enhancing the DNs performance through the integration of multiple DG technologies in order to optimize the active power losses, the fast voltage stability index and the total costs, considering the DGs penetration level as well as the DG units’ operating power factor constraints. The proposed algorithm has been implemented using MATLAB software and applied on three-benchmark IEEE test systems (30-bus, 33-bus and 300-bus) as different models of electric power networks. The attained results show that the suggested optimization platform especially using MSCA, is more effective and successful in determining and finding better results than existing results.

Overview and Feasibility of Floating Solar Photovoltaic System in Nepal

As a next generation technology, Floating Solar Photovoltaic (FSPV) System has had a remarkable growth in the field of Renewable Energy since 2014 with an installed capacity of more than 200 MWp as of 2017. Interest in FSPV system is on the rise compared to its land-based counterpart due to significant benefits like an increased efficiency of the panel, omission of land-related cost and cost of the mounting structure along with environmental benefits like water conservation of the reservoir through a reduced rate of evaporation and containment of algae boom. In this paper, the overall benefit of exploiting FSPV system in case of Nepal has been explored and the techno-economic feasibility of such system in Nepalese scenario has been analyzed. Improvement in efficiency of the panel has been calculated mathematically which also seems to support results from previous works. After analyzing the techno-economic benefits, it was found that FSPVs, even though having a marginal financial profit at current PPA rate of Rs. 7.3/kWh, can still prove beneficial if used concomitantly with storage type hydropower plants.

Project planning and control analysis for suburban photovoltaic alternative electric power supply in Southwestern Nigeria

Alternative photovoltaic (PV) electric power systems are designed for suburban residential complexes in Nigeria’s Southwestern region as succour to erratic grid power supply. The initial project in suburban Ibadan, Oyo State was analyzed as model for other stakeholders in the region. A project planning framework was used for analysis. The project scope, cost and time specifications were determined: a 7 MW PV system designed over 35 acres, estimated power generation costs of US$2.56 per watt, estimated total project cost of $17.9 million, estimated cost at completion of $21.6 million, and estimated completion time of 12 months 19 days. Techno-economic benefits include 15.83 GWh of electricity and revenue of US$1.74 million per annum per state. Environmental benefits include annual elimination of 1.58 million litres of diesel fuel use and 4241.8 metric tonnes of CO2 emissions from the atmosphere. The schemes were determined to be non-viable at the extant electricity utility rates of US$0.07 per kWh but viable at electricity utility rate of $0.11 per kWh with payback period of 16 years. The study concluded that in spite of the expected project time delay and budget overshoot, the project was viable and a suitable template for Southwestern Nigeria.

Techno-Economic evaluation of single and multi-purpose grid-scale battery systems

As the technological evolution continuously flourishes, battery cell prices plunge and political debates about sustainable innovation heat up, the economic attractiveness of battery energy storage systems gets stimulated. The recent development in the German political sphere is driving the transformation in energy generation from traditional to sustainable energy supply. Whereas most research analyzes the potential of single-purpose battery energy storage systems, few studies prove the techno-economic benefits of this technology and its ability to serve multiple purposes. This study evaluates the economic implications of such batteries with a simulation model designed to optimize the return of investment and net present value for a project scope of 20 years while serving as frequency containment operators. The model simulates one year with real data of the Continental European grid frequency, the EPEX electricity market, and load and generation profile of a northern German distribution grid and scales the results with respect to the battery's degradation. Enhanced frequency response and primary control reserve are compared on their technical and economic feasibility as well as their combination with peak shaving applications. The results of the simulations indicate that the enhanced frequency response has the highest profitability and performance for battery energy storage systems. Adding the peak shaving application can improve the profitability and de-stress the grid. In any case, larger battery dimensions regarding capacity and power are linked to higher investment costs and thereby reduce the overall return on investment.

A novel severity performance index for optimal allocation and sizing of photovoltaic distributed generations

Optimal allocation and sizing of the distributed generations (DGs) attract great attention of many researchers all over the world. In this study, the problems associated to optimal DGs allocation and sizing are divided into two sub-problems. One of them deals with the DGs allocation at the critical buses and the other aims to select the optimal size of these DGs. A novel severity performance index (SPI) is introduced to evaluate both the power system reliability and quality. The crow search (CS) is integrated with PSO not only to collect the merits of both CS and PSO but also to solve the optimal power flow problem including multi-DGs allocated at the critical buses for the IEEE 30-bus test system. Detailed comparisons of four distinct DGs allocation cases are presented, discussed, and analyzed. The simulation findings proved that the DGs allocated based on the multi-objectives (SPI, total fuel costs; FC; and power losses; PL) have a superior performance compared to other cases in terms of voltage profile, branches loading, power losses, and total costs. Therefore, the multi DGs is preferred to be allocated based on these multi-objectives (SPI, FC, and PL) in order to attain additional techno-economic benefits to the power system.

Renewable hydrogen production: A techno-economic comparison of photoelectrochemical cells and photovoltaic-electrolysis

The present paper reports a techno-economic analysis of two solar assisted hydrogen production technologies: a photoelectrochemical (PEC) system and its major competitor, a photovoltaic system connected to a conventional water electrolyzer (PV-E system). A comparison between these two types was performed to identify the more promising technology based on the levelized cost of hydrogen (LCOH). The technical evaluation was carried out by considering proven designs and materials for the PV-E system, and a conceptually design for the PEC system extrapolated to future, commercial scale.The LCOH for the off-grid PV-E system was found to be 6.22 $/kgH2, with a solar to hydrogen efficiency of 10.9%. For the PEC system, with a similar efficiency of 10%, the LCOH was calculated to be much higher, namely 8.43 $/kgH2. A sensitivity analysis reveals a great uncertainty in the LCOH of the prospective PEC system. This implies that much effort would be needed for this technology to become competitive on the market.Therefore we conclude that the potential techno-economic benefits that PEC systems offer over PV-E are uncertain, and even in the best case, limited. While research into photoelectrochemical cells remains of interest, it presents a poor case for dedicated investment in the technology's development and scale-up.

Capacity benefit margin assessment in the presence of renewable energy

Energy sustainability and reliability issues have created great concerns globally, instigating various utilities to create interconnections with one another for system security and techno-economic benefits. Capacity benefit margin (CBM) is the amount of transmission capacity reserved between interconnected systems for emergency power exchange between utilities. It is usually estimated by evaluating the reliability of the generating units of interconnected systems to know the amount of external generation required during emergency supply shortage. Various techniques have been employed in literature to evaluate CBM. However, despite the global awareness on the continuous shift from conventional power generation sources to renewable energy sources, the assessment of CBM in the presence of renewable energy has not been addressed. Moreover, existing techniques for CBM calculation are based on iterative optimization and may not scale well to more than one deficient area. To solve these issues, this article incorporates wind power (WP) generation in CBM computation. The proposed technique is based on graph theory and can be used to calculate CBM in the presence of multi-deficient areas and renewable energy sources, in particular, WP. Simulations using the IEEE 24-bus reliability test system in MATLAB show that the proposed technique is significantly better in terms of scalability and accuracy as compared to existing techniques. The proposed technique can be employed by utilities for CBM estimation in the presence of renewable energy sources.

Influence of rectifiers on the techno-economic performance of alkaline electrolysis in a smart grid environment

Abstract Alkaline electrolysis is a mature technology with long lifetimes and high reliability. However, the conventional electroylzer systems are only designed for constant operation at full load. Depending on the employed rectifiers, they show reduced efficiencies in dynamic operation. Recent advances in rectifier and electrolysis systems allow their dynamic operation in a smart grid environment with volatile renewable energy generation. This study investigates the techno-economic benefits of a recently developed process current source in combination with an alkaline electrolyzer, compared to three frequently employed conventional rectifier topologies. The smart grid simulation regards three scenarios with differently scaled electrolyzer units and therefore, varying amounts of surplus energy. Simulation results display an increased amount of annually produced hydrogen from 2250 MWhH2,LHV for the worst conventional system to 3050 MWhH2,LHV for the new process current source, in the scenario with the highest electrolyzer scaling. In this case, a larger electrolysis system results in more partial load operation and here, the process current source outperforms all conventional rectifiers in amount of generated hydrogen as well as in the economic viability. The levelized costs of hydrogen are always more than 0.5 €/kgH2 cheaper, especially in highly dynamic operation.

Planning optimization and stochastic analysis of RE-DGs for techno-economic benefit maximization in distribution networks

In practical distribution networks of long-distance feeders, load's expansion and seasonal load variations seriously affect the system performance. In the context of the present advancements in D.G.s, especially generating from the renewable energy (RE) sources along with the recent support of policy-makers, it is smart consideration to transform the long-distance conventional distribution networks into the optimal DG-integrated systems for the augmentation of the technical and economic benefits jointly. In this article, a novel methodology, namely Hybrid-PPSO-GSA, is proposed and applied to maximize the techno-economic benefits via an optimal RE-DG integrated system. The proposed methodology focused on the optimal placement and sizing of RE-DG into the distribution system, considering the stochastic analysis of RE-DGs such as W.T. and P.V. with multiple objectives. The Hybrid PPSO-GSA was tested on standard 69-bus systems and particularly implemented on 94-bus long-distance practical distribution feeder located in Portuguese; for power loss reduction, voltage profile, and stability enhancement. Apart from the reduction in the power loss and voltage improvement, the energy loss can be improved jointly, resulting in the coupled techno-economic contribution of the DG-integrated system. Simulations are conducted for various scenarios, and the obtained results demonstrate the merits of the proposed scheme.

Optimal Allocation of Distributed Generation Considering Protection

The integration of distributed generation (DG) into the power grid has increased in recent years due to its techno-economic benefits for utilities and consumers. However, due to the fact that distribution systems were not originally designed to accommodate such DG units, many challenges are being faced by utilities to seamlessly integrate them into their systems. One of the critical challenges is their effect on protection system settings and coordination. The DG units will affect the pickup current settings of the protection relays, coordination between the primary and secondary relays, and even the direction of the fault current. Failing to consider DG’s effect on the protection system may lead to serious equipment damage or system failure, causing huge financial setbacks for utilities. To that end, this work proposes a new dynamic approach to optimally allocate different types of DG units over the planning horizon. The objective is to minimize the overall costs of the system while taking into consideration the intermittent nature of renewable DG and the impacts on the protection system. Simulation results have been developed on a typical distribution system to prove the effectiveness of the proposed approach.

Techno-economic benefits of grid-scale energy storage in future energy systems

The increasing penetration of renewable energy sources in the power sector represents an important challenge for energy systems due to their elevated intermittency. Energy storage constitutes a key component for its ability to add flexibility to the system allowing further integration of these renewable sources. Therefore, the aim of this study is to analyse the impact of grid-scale energy storage in a hydro dominated power system with increasing renewable generation shares. The Colombian energy system is used as a case study. The model used in this work is built using the EnergyPLAN tool and validated against actual data. Successively, the techno-economic effects of large-scale energy storage technologies are assessed on three different future scenarios for the year 2030. The results evidence that increasing levels of storage could allow significant reductions in both the curtailed energy and the total fuel consumption of the country. The best-case scenario shows an estimated 67% reduction in the emission intensity of the power sector by 2030 compared to the baseline scenario.