Years Of Payback Period Research Articles

A systematic design of integrated palm-oil biorefinery networks: Identifying sustainable solutions

This paper presents a comprehensive and systematic analysis of synthesis and design of sustainable palm oil integrated biorefinery networks involving multiple platforms of bioresources for sharing materials, energy, and facilities to obtain a more sustainable solution. There are three main processing platforms consisting of palm oil, palm biomass, and biogas from palm oil mill effluent (POME-biogas). The alternatives are generated from a superstructure of each platform representing different products that can be made and their established processing routes. Utilizations of glycerol, bio-syngas, and CO2, which are by-products of the palm oil, palm biomass, and POME-biogas platforms, respectively, are also considered as three other platforms. Different scenarios of materials, energy, and facility integration among the platforms are analyzed by considering economic benefits together with CO2 emissions, as well as Life Cycle Assessment (LCA), which includes climate change impact and other environmental impact categories. Analyses of the design of the palm oil integrated biorefinery network with multiple process networks and heat integration point to the achievement of more sustainable solutions for production and consumption compared to the scenario of business as usual (BAU). The sustainable palm oil integrated biorefinery network corresponds to economic improvement and CO2 reduction potential as well as satisfying environmental impacts. The analysis results show that the palm oil integrated biorefinery network alternatives can provide high economic potential and less environmental impacts compared to without any integration. The best non-tradeoff solution proposes the integration of palm biomass and POME-biogas platforms for bio-methanol production and the integration of palm oil platform with glycerol production to produce 1,2-propanediol as an additional product. It offers 23.5 million dollars per year of economic value-added benefit with 2.9 years of payback period while also reducing the environmental impacts. Wind power and river water are selected to maximize profitability options for electricity and freshwater supplies, respectively.

Assessment of costs and benefits of green retrofit technologies: Case study of hotel buildings in Sri Lanka

With the rising impact of greenhouse gas emissions, resource depletion, and the global interest in sustainability advancements within all sectors, construction industry practitioners are also interested in incorporating sustainable features and practices into their buildings. Nevertheless, most of the commercial buildings in Sri Lanka had been constructed during the unprecedented urbanization between 1995 and 2010, thus, before sustainable concepts became more prominent. Therefore, existing buildings in Sri Lanka is experiencing ever-increasing energy consumption, resulting in higher utility costs, with which green retrofitting has become imperative, notably in hotel buildings. This study, therefore, conducted an economic evaluation of three existing hotel buildings to establish an account of the cost implications and saving potentials of different green retrofit technologies. The data collected through document reviews and site visits were analysed using net present value and simple payback period calculations. Although number of retrofitting technologies have been incorporated in the selected buildings, more weight has been given to incorporating technologies to achieve energy efficiency and indoor environmental quality. Considering the financial viability, all the implemented green retrofits have a positive return on investment and less than ten years of payback period, except LED televisions. Amongst the implemented retrofits, biomass boilers, energy-efficient chillers, and solar PV systems have the highest energy-saving efficiency, followed by VFDs and LED lighting, while LED televisions have the lowest. The study's findings contribute to industry practitioners identifying the appropriate green retrofits based on the cost implications and savings potential and enhancing the sustainability of the built environments by reducing greenhouse gas emissions and depletion of natural resources.

Design and multi-objective optimization of a multi-generation system based on PEM electrolyzer, RO unit, absorption cooling system, and ORC utilizing machine learning approaches; a case study of Australia

The geothermal systems' capability to produce various products persuades the design of a novel hybrid system, including power, cooling, freshwater, and hydrogen. Australia, with numerous geothermal sources and the tendency of hydrogen utilization as fuel, is considered a case study. The designed system is analyzed from energy, exergy, and economic viewpoints. Also, the artificial neural network is implemented to optimize the system's operation. Hence, the accuracy of four artificial neural networks in optimizing and predicting systems' performance is compared. Furthermore, four double-objective and four triple-objective optimization scenarios are considered to achieve the best optimum state from different viewpoints. The mean absolute Error value of 2.28×10−14 to predict the exergetic efficiency in the testing procedure is the best algorithm. The system provides 1263 kW net power with 39.89% exergy efficiency and 2.13 years of payback period at the base condition. The exergy efficiency-net present value scenario represents the best performance in which the net power, hydrogen, and freshwater production rates reach 3946 kW, 8.73 kg/h, and 152 kg/h, respectively. Subsequently, the exergy efficiency, payback period, and net present value are estimated at 46.27%, 1.84 years, and 19.52 M$.

Decision Support Tool for the Optimal Sizing of Solar Irrigation Systems

Solar photovoltaic (PV) irrigation is increasingly used in agriculture, driven by its low operation cost and virtually zero emissions, providing electricity access in rural areas. However, the high investment cost requires an optimal design. The objective of this work was to develop a user-friendly tool to optimally size a PV generator that satisfies crop irrigation needs under local constrictions. The ODSIS (Optimal Design of Solar Irrigation System) tool, was organized in three calculation modules, preceded by two complements, which determine the daily crop irrigation needs and power demand of the pumping system. Then, the first module sizes the PV plant, considering a multiplication factor, and provides the PV production potential throughout each day of the season. The second and third modules evaluate the total investment cost and equivalent greenhouse gas emissions avoided by comparison with traditional energy sources. This tool was applied to a case study in Senegal for which a multiplication factor of 1.4 was obtained for the optimal PV plant size. Between 22% to 64% of the investment cost corresponded to the PV pumping system, depending on the irrigation technique. The use of PV energy in the case study would represent an annual economic saving for the farmer after 5 to 8 years of payback period, avoiding the emission of between 29.8 and 37.9 tCO2eq/year for the case study area.

Feasibility Study of Road Improvement Geotextile using Discounted Cash Flow Method: Study Case of PT Berau Coal

Lati Mine Operation is one of the open pit mining operational owned by PT Berau Coal. This area has overburden removal production annual target 134,556,000 BCM and coal getting 8,631,000 MT in year 2022. In the first semester of 2022, actual overburden removal was achieved in 94% under the year to date plan. Based on pareto loss production analysis, the biggest lost contributor of overburden removal was came from hauler productivity parameter. The root cause of hauler productivity problem is material used for road surfacing which has implication to road condition. Road surfacing material was came from redisturb material that cause low bearing capacity on subgrade layer and impacted to road damage on the surface. One of improvement can be done to increase productivity and reduce cost maintenance is investment of geotextile implementation to mine road reinforcement. Therefore, project investment need to be evaluated through a comprehensive financial analysis to get financial feasibility of this project. This research will use capital budgeting analysis to evaluate the financial feasibility, including sensitivity analysis and risk analysis. The baseline of feasibility analysis regarding improvement project shows good result with Net Present Value (NPV) worth IDR 2.232.785.016, Internal Rate Return (IRR) of 42,56%, 1,46 of Profitability Index (PI) , and 1,2 years of payback period (PBP). Based on Monte Carlo Simulation, the probability of this project failing (NPV < 0) is 0%, or in the other words, there is no probability that the NPV project will generate negative value or loss in this project. In conclusion, mine road improvement using geotextile is feasible and potentially give optimum impact on increase productivity and cost efficiency regarding to mine road maintenance.

A dual-mode novel Parabolic Trough Collector for process heating applications in small scale industries—Thermo-hydraulic and performance investigation

Only a few industries worldwide use solar heat for industrial processes, despite the fact that it is a proven and cleaner solution. More over, Small-scale industries need hot water and low-enthalpy steam, but such systems receive scant attention due to the active nature of Parabolic Trough Collectors as well as the use of less efficient flat plate technology in this temperature range. This delineate the opportunity for research focus in efficient passive technologies especially in low temperature range. In this regard a novel dual mode Parabolic Trough Collector based on an Open Natural Circulation Loop (PTC-ONCL) is proposed here. Focus of this work is to assess the proposed system’s suitability for process heating applications requiring hot water/low enthalpy steam, especially in rural areas. Experiments are conducted on an in-house prototype. A novel methodology for correlating actual solar data to the input heat load for the in-house test facility is developed. Five representative solar days are considered for individual tests. Startup, transient, and efficiency parameters are evaluated. Productivity, industrial viability, and environmental impact are also accessed. Throughout the test, the loop maintained a stable flow, where the start-up oscillations, thermal oscillations and type-I instabilities are observed. The system operates at an unprecedented efficiency of 72 ± 4% in hot water mode and 70 ± 5% in Steam generation over a 7 h period. The economic analysis shows an ambitious Levelized Cost of Heat of 2.8 cents/kWh, with a payback period of 3.21 years. Moreover environmental study shows its huge potential in reducing the CO 2 emissions. A dimensionless index is proposed to represent the solar day and is correlated to predict the average water temperature and steam generated with RMSE values of 0.98 °C and 0.125 kg respectively. The solar day index comprehends the total irradiation, wind velocity and the ambient temperature. The proposed PTC-ONCL system is capable of producing an annual average of 8.67 kgday −1 and/or 150 L of hot water at an average temperature of 89.07 °C. The results, and the system’s low cost and near-maintenance-free nature demonstrates its capability in the desired application, both technologically and economically. • A passive Parabolic Trough Collector based on an Open Natural Circulation Loop for process heat at low temperature. • New methodology correlates actual solar data to input for an in-house test facility. • Generates 8.67 kg of steam/ hot water at 89 °C on a yearly average with 65% efficiency. • Levelized Cost of Heat of 2.8 cent/kWh & 3.2 years of payback period found promising. • Dimensionless solar day index includes combines irradiation and ambient condition.

Recycled Aggregates Production Through Economic Perspectives

Construction and Demolition Waste (CDW), especially laboratory waste and concrete debris from construction, manufacturing errors, and demolition of existing structures, is posing challenges to the urbanization. As nowadays the aforementioned waste is disposed in landfills, this diminishes the development opportunity of cities. Although there are standards and research pointing out the application of recycled concrete aggregates in proper proportion, the theory has never been put into practice. This research aims to present feasibility of applying recycled aggregates through Bangkok’s economic perspectives. It is found that the investment in recycled aggregate plants takes nine years of payback period. Besides, the sensitivity analysis suggests that implementing certain strategies, such as imposing a landfill tax increase and applying dumping fee will significantly shorten the payback period of recycling business.

Comprehensive assessment of a green cogeneration system based on compressed air energy storage (CAES) and zeotropic mixtures

This paper proposes combining the solar-based adiabatic compressed air energy storage system to respond to the grid peak-time demand. Two ejector refrigeration cycles with zeotropic mixture working fluid are employed as the waste heat recovery system. Eight different zeotropic mixtures were candidates for the first ejector refrigeration cycle working fluid. Its working fluid selection was carried out via studying their mass fraction variation on the system's performance. Among the considered zeotropic mixture, the Pentane/Butane with a mass fraction of 0.5–0.5 presented the best performance. Comprehensive thermodynamic and thermo-economic analyses were performed to evaluate the system's performance. The proposed plant could provide 991.89 kW power for the grid's peak-shaving and 170.7 kW cooling load with 35.82% and 33.19% round trip and exergetic round trip efficiencies and 7.75 years of payback period. A parametric study was performed to investigate some main parameters variation's effect on the system's performance indexes and demonstrated that the cavern inlet pressure has the highest impact on the system's power production, and charging to discharging pressure ratio influenced the round trip, exergetic round trip efficiencies. Finally, triple-objective optimization is applied, obtaining 35.87%, 33.23%, and 7.72 years of round trip efficiency, exergetic round trip efficiencies, and payback period.

Feasibility Study of the Technical and Economic Performance of Grid-Connected PV System for Selected Rooftops in UTHM

This paper presents the feasibility study of the technical and economic performances of grid-connected photovoltaic (PV) system for selected rooftops in Universiti Tun Hussein Onn Malaysia (UTHM). The analysis of the electricity consumption and electricity bill data of UTHM campus show that the monthly electricity usage in UTHM campus is very high and expensive. The main purpose of this project is to reduce the annual electricity consumption and electricity bill of UTHM with Net Energy Metering (NEM) scheme. Therefore, the grid-connected PV system has been proposed at Dewan Sultan Ibrahim (DSI), Tunku Tun Aminah Library (TTAL), Fakulti Kejuruteraan Awam dan Alam Bina (FKAAS) and F2 buildings UTHM by using three types of PV modules which are mono-crystalline silicon (Mono-Si), poly-crystalline silicon (Poly-Si) and Thin-film. These three PV modules were modeled, simulated and calculated using Helioscope software with the capacity of 2,166.40kWp, 2,046.20kWp and 1,845kWp respectively for the total rooftop area of 190,302.9 ft². The economic analysis was conducted on the chosen three installed PV modules using RETScreen software. As a result, the Mono-Si showed the best PV module that can produce 2,332,327.40 kWh of PV energy, 4.4% of CO₂ reduction, 9.3 years of payback period considering 21 years of the contractual period and profit of RM4,932,274.58 for 11.7 years after payback period. Moreover, the proposed installation of 2,166.40kWp (Mono-SI PV module) can reduce the annual electricity bill and CO2 emission of 3.6% (RM421,561.93) and 4.4% (1,851.40 tCO₂) compared to the system without PV system.

Design and simulation of a rooftop PV System in Taylor’s University Lakeside Campus

Solar photovoltaic (PV) system is proven to be a future-proof type of power generation for growing economies. There are almost zero pollutants released, low maintenance cost with high reliability as the lifespan of a solar PV stretches up to 30 years, a well-sought alternative form of sustainable energy. Moreover, the electricity consumption in Taylor’s University (TU), Malaysia is very high, as a consequence, a huge fraction of the fund is used to settle an RM450,000 electricity bill on average annually. In this paper, the study focused on how to reduce electricity consumption in TU by proposing a design of a comprehensive solar PV system. PVSYST and Sketchup software are used to design and analyze the PV system. In the present study, a Grid-Connected Photovoltaic (GCPV) mounted on the available roof space of TU is investigated. Also, a detailed economic analysis that includes the payback period and annual savings achieved through the proposed PV installation is analyzed. Annual savings of RM 267,621.00 can be made upon utilizing the proposed idea. Besides that, TU would be able to recover the initial investment cost in approximately 8 years of payback period, proving that the implementation of a 433kWp of solar PV unit is a smart option to address the sustainable energy goals.

Energy, Exergy, Economic, Environmental (4Es) comparative performance evaluation of dewpoint evaporative cooler configurations

The performance of different configurations of Maisotsenko (M-cycle) based dew point evaporative cooler is significantly effected by operating range in a certain climate. Moreover, the system's economic and environmental aspects are equally important for its viability. In the current study, experimentation is conducted to explore the impact of the wide range of operating parameters on performance. The experimental results are further utilized for 4E (energy, exergy, economic and environmental) analysis of counter and cross flow configurations analysis along with resource consumption. Results show that supply temperature increases around 70% and 78%, cooling capacity increase about 87% and 60%, and energy efficiency ratio decreased 13.7% and 25.5% at low to high operating range. The maximum and minimum exergy efficiency of counter and cross flow are 46%, 18.23%, and 52%, 21.58%, respectively. Furthermore, counter flow configuration consumes 39% and 2.7%, 24.65% and 35%, 21.4%, and 38% more water and electricity consumption at low, medium, and high operating conditions. The decrease in present worth cost at low to high-interest rates is around 31.8% for counter flow and 29.6% for cross flow at a high range of operating parameters. The counter flow system at 13% interest rate has 48%, 34.6%, and 28% more life cycle cost than cross flow. Around 59%–34% more net present value with 1.3 years and 1.96 years of payback period at the high range of operating parameters. Moreover, the counter and cross flow configurations produce 158 to 342.57 kgCO2/month and 153 to 329 kgCO2/month, respectively when operated at low to high operating parameters range.

Techno-Economic Assessment of On-Farm Anaerobic Digestion System Using Attached-Biofilm Reactor in the Dairy Industry

In this study, a techno-economic assessment of an on-farm biogas system using an anaerobic biofilm reactor utilizing cow manure as a fermentation substrate was evaluated. A projection model was developed using Microsoft Excel software with three outputs, the size and dimension of a bioreactor, experimental microbial kinetic studies, and the economic studies based on the experimental results. Characterization analysis of cow manure wastewater showed the total solid (TS), total volatile solid (TVS), total carbohydrate (TC), chemical oxygen demand (COD), and pH values which were 10.95 g/L, 8.65 g/L, 6.65 g/L, 57.80 g/L, and 7, respectively. Using the modified Gompertz equation for the microbial studies, it was found that, at 37 °C and 20 days hydraulic retention time (HRT), the biogas yield was 934.54 mL/gVS, the volume of biogas produced was 11.28 m3/d, and 22.56 kWh of electricity was generated. The Gompertz prediction helps to determine the optimal HRT for the system so that the microorganisms are at their optimum stage to produce biogas. The economic analysis was done, and the results illustrated that, when the rate of cow manure produced was at 55 L/day.cow, the net present value (NPV) was RM 611,936.09, with a 13% internal rate of return (IRR), 0.14 return on investment (ROI), and 7.02 years of payback period (PP). By developing a techno-economic assessment that included all the necessary parameters such as sizing of the bioreactor, microbial kinetic studies, and economics of the plant, farmers could easily implement the system into their farms. This model showed that the anaerobic digestion system utilizing an attached biofilm with cow manure as a fermentation inoculum and substrate was applicable on an industrial scale to generate electricity and reutilize to the farm, at the same time generating additional income from the production of fertilizer.

A novel heating strategy and its optimization of a solar heating system for a commercial building in term of economy

The existing solar heating system has high cost and a poor economy and is difficult to popularize because it needs a large area of solar collector and a volume of storage tank. Although many researchers attempted to optimize the system, it still could not reduce the initial cost significantly. To solve this problem, this paper presented a novel heating strategy for a specific commercial building and optimized it in term of economy. The novel strategy adopts a time-share heating method to reduce the initial cost and operating cost according to the heating requirement of the specific commercial building. In this study, a general model of a solar heating system based on TRNSYS was established. The combined effect of collector area, storage tank volume and electricity price on the economy was analyzed. The optimal matching ratio between storage tank volume and the collector area was obtained, and the heating performance in optimal matching was evaluated. The results showed that when the electricity price is $ 0.12, Vt/Ac = 0.05 has the maximum net present value (NPV), which has good economy with 6 years of payback period. This study presented an effective approach to solve the economic problem of solar heating.

Optimizing a PV/Diesel Hybrid System in Oil and Gas Industry using Metaheuristic Techniques

The purpose of this work is to develop a systematic optimization methodology for utilizing renewable energy resources, specifically Photovoltaic (PV), in Oil & Gas Industry. The study has been applied on sucker rod pump, which is considered as the conventional technique for lifting crude oil (artificial lifting). The pump is operated with integrated solar assisted system and standalone diesel generator. The annual energy requirements using the levelized cost of energy (LCOE) for a sucker rod unit at western desert in Egypt have been evaluated. A metaheuristic optimizer (Water Cycle Optimization Technique WCOT) has been utilized to optimize the PV contribution in the hybrid PV/diesel system proposed. The results have shown that the hybrid system can provide up to 25% reduction in the LCOE with respect to the running diesel generator 24/7 system. Over and above, by considering the annual saving, only two years of payback period will be needed.

Solar PV powered water pumping system – A review

Diesel-powered pumps are widely used for irrigation purposes. However, due to an increase in the price of oil in the international market, harmful emissions from burning of it, high maintenance cost, and short lifetime have been forced to find some alternative. Renewable energy has the potential to limit the use of fossil fuel, as researchers are shifting towards a solar-powered water pumping system. As solar is available in large amounts and almost everywhere even in remote locations, which makes a good alternative to the diesel-powered water pump. The main aim of this review is to present a short overview of the solar PV powered water pumping system, its important components, applications, and India scenario. Economic and environmental aspects were also discussed. Solar PV water pumping system is found to be more economical, eco-friendly, reliable, with less maintenance and a long life span in comparison to diesel-powered water pumps. 4–6 years of payback period is found for some of the systems. The recent Indian subsidy provided and the latest scheme available for installation purposes are also discussed in the work.

Preliminary Design of Phycocyanin Production from Spirulina platensis Using Anaerobically Digested Dairy Manure Wastewater

Phycocyanin is a blue pigment that is found in cyanobacteria such as Spirulina platensis. Its ability to provide stable and non-toxic blue color makes its market value is so high that it reaches USD 112.3 million in 2018. However, the cultivation of S. platensis to produce phycocyanin can only be carried out by large-scale industry, due to high operating costs of synthetic medium such as Zarrouk. We considered the use of Anaerobically Digested Dairy Manure Wastewater (ADDMW) as an alternative for growth medium to produce phycocyanin from S. platensis. A laboratory-scale study was conducted to determine the optimum composition of the medium containing ADDMW and NaHCO3 as a carbon source for S. platensis. We found that the ADDMW medium combined with 16.8 g/L NaHCO3 and 25 g/L NaCl resulted the highest productivity of phycocyanin among the other variations. Industrial-scale economic analysis of this integrated cultivation method showed its economic feasibility using 10 years lifetime analysis. Highest GPM (gross profit margin) obtained is 12.40 with IRR (internal rate of return) 23% which give 3.13 years of payback period. Futher study is needed on technical aspect and actual implementation of industrial scale design.

Technical-economic analysis for a green ammonia production plant in Chile and its subsequent transport to Japan

Green ammonia can be produced using fossil fuels or any renewable energy source combined with heat or electricity. Chile has one of the highest rates of solar irradiation and also the environmental conditions that support the development of solar industry. Other renewable sources of energy are the wind and the hydraulic dams. These energies could be used to generate ammonia by a standard method such as the Haber-Bosch process, which transforms hydrogen and nitrogen using high temperatures and a catalyst. The ammonia has several desirable characteristics that suggest its use as a way to store hydrogen. Firstly, it can be liquified under mild conditions. Secondly, the ammonia has a high weight fraction of hydrogen. Thus, it is deemed necessary to study technical and economic variables that may support the use of green ammonia as an energy carrier for hydrogen. The aim of this work is to develop a technical-economic analysis about the production of ammonia using hydrogen by means of electrolysis (carried out with solar, wind, and hydraulic renewable energies). The aforementioned green ammonia would be produced in Chile and it would be necessary to transport it to Japan. Sensitivity analysis of main parameters (plant operating hours, size of the ammonia synthesis plant - related to the capacity of the electrolysis plant size in MW-, electricity price, electrolyzer cost, Haber-Bosch cycle cost, and ammonia sales price) was performed to report what factors are primordial at the moment of carried out techno-economic analyses. An optimization process that minimize the NPV was run in order to settle the most convenient size of the electrolyser stack. A net present value (NPV) of base case is €77,414,525 and 7.62 years of pay-back period were calculated for this green ammonia production plant, which considered hydrogen production via electrolysis, Haber-Bosch processes, and trade values of different operational units. The sensitivity analysis has determined that the main variables affecting the NPV are the size of the ammonia synthesis plant and the electricity price. Furthermore, by considering triangular probability distribution of specific variables, it was observed that with a 95% of confidence, the NPV would be positive with a 76.1% of occurrence. The optimization process defined that a stack of 164.21 MW would be the most convenient electrolyser stack dimension, which was estimated by considering all different effects over the operational expenditure (OPEX), capital expenditure (CAPEX), and investments risk. Therefore, the hydrogen production in Chile and its transportation to Japan using ammonia as an energy carrier would be a technically viable and profitable solution, which also has environmental benefits.

LCA-Based Economic Benefit Analysis for Building Integrated Photovoltaic (BIPV) Façades: A Case Study in Taiwan

ABSTRACTSolar energy is one of the major sources of alternative and green energies that humanity need now and will continue to need in the future. There are now a large number of R&D activities on solar power generation facilities and equipment around the world. Located in a subtropical region, Taiwan is rich in solar energy resources; therefore, how to effectively use and store solar energy is a research topic of great interest to Taiwan. The main purpose of this study explores the economic benefits of building-integrated photovoltaics (BIPV) facilities and equipment by analyzing the net present values (NPV) and payback period of the BIPV façade of a shopping mall in Taiwan over its lifecycle. The NPV and payback period analysis results both indicate that the BIPV façade in the case study reaches its breakeven point within 10 years of payback period and 16 years of NPV during a life cycle of 20 years. By showing BIPV investments can bring an acceptable range of benefits profits, this study hopes to provide references for promoting the photovoltaic (PV) industry.

Economic analysis of a new class of vanadium redox-flow battery for medium- and large-scale energy storage in commercial applications with renewable energy

Interest in the implement of vanadium redox-flow battery (VRB) for energy storage is growing, which is widely applicable to large-scale renewable energy (e.g. wind energy and solar photo-voltaic), developing distributed generation, lowering the imbalance and increasing the usage of electricity. However, a comprehensive economic analysis of the VRB for energy storage is obscured for various commercial applications, yet it is fundamental for implementation of the VRB in commercial electricity markets. In this study, based on a new class of the VRB that was developed by our team, a comprehensive economic analysis of the VRB for large-scale energy storage is carried out. The results illustrate the economy of the VRB applications for three typical energy systems: (1) The VRB storage system instead of the normal lead-acid battery to be the uninterrupted power supply (UPS) battery for office buildings and hospitals; (2) Application of vanadium battery in household distributed photo-voltaic power generation systems; (3) The wind power and solar power stations equipped with the VRB storage systems. The economic perspectives and cost-benefit analysis of the VRB storage systems may underpin optimisation for maximum profitability. In this case, two findings are concluded. First, with the fixed capacity power or fixed discharging time, the greater profit ratio will be generated from the longer time or the larger capacity power. Second, when the profit ratio, discharging time and capacity power are all variables, it is necessary to find out the best optimisation result containing the highest profit ratio, the lowest capacity power and the shortest payback years. After the algorithm, it can be concluded that when t=8h (including 3h high peak period and 5h peak period), and P=94.7MW, the shortest years of payback period are 3.4years, and the profit ratio is 196.5%.

Techno-economic assessment of a heat-integrated process for hydrogenated renewable diesel production from palm fatty acid distillate

Hydrogenated renewable diesel (HRD), which is defined as paraffinic hydrocarbon derived from vegetable oil and animal fat, has received consideration worldwide as an alternative diesel fuel. In this work, HRD production from palm fatty acid distillate (PFAD) feedstock was designed and techno-economic evaluation of a heat-integrated HRD production plant was performed. HRD production for a PFAD feed flow rate of 579 g s−1 was simulated in Aspen Plus® software as the base-case model; the minimum energy consumption was calculated using pinch point analysis, and a heat exchanger network of heat integration was designed. Subsequently, the modified heat integration HRD production plant was subjected to economic analysis to determine the HRD production attractiveness to investment. It was found that investment in HRD production would be attractive as the fixed capital investment cost of the production plant was 20.735 M$. With a HRD selling price of 950 $ m−3 the project gave 39.4% of return on investment and 3.0 years of payback period. If the company has PFAD readily available, a HRD production project was attractive to investment with a NPV of 61.89 M$.