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A techno-economic analysis (TEA) was conducted to evaluate the economic profitability and feasibility for a H2 energy storage system using an alkaline and a polymer electrolyte membrane water electrolysis for 1 MW water electrolysis operation. Many economic analysis methods such as itemized cost estimation, profitability analysis using a cumulative cash flow diagram, and uncertainty analysis employing a Monte-Carlo simulation method were utilized to perform a TEA. In particular, a renewable energy certificate (REC) was considered as an additional benefit of a renewable energy use. From itemized cost estimation, respective levelized costs of H2 of 7.21 and 9.19 $ kgH2−1 were obtained for both H2 energy storage systems in an alkaline and a polymer electrolyte membrane water electrolysis by considering current economy situation and therefore it is still difficult to be cost-competitive compared to a commercial H2 production cost. From profitability and uncertainty analysis results, an appropriate REC weight was confirmed in terms of discounted profitability criteria like a discounted payback period, a net present value, a present value ratio, and a discounted cash flow rate of return. In addition, a REC weight was affected on a net present value compared to a REC trading cost fluctuation.

This study presents an economic analysis of grid-connected residential rooftop PVs in Turkey under the current feed-in tariff (FiT) scheme. Three solar parts are formed on the solar map of Turkey to discuss the effect of solar radiation differences between regions on the feasibility of the systems. Nine provinces are selected for a nationwide analysis. 5 kW rooftop PVs are simulated using HOMER Grid. Discounted Payback Period (DPBP), Internal Rate of Return (IRR) and Profitability Index (PI) are used to ensure the viability of the systems from all aspects. DPBP below 8 years, IRR above 13.12%, and PI above 2 are considered feasible. The results showed that current DPBP, IRR, and PI of the systems are in the range of 7.75–14.43 years, 13.68%–6.87%, and 2.02–1.28, respectively. The systems are attractive only in one province in the southern part, and far from being investable in the northern part. A sensitivity analysis is performed to analyze the effect of varying FiT and PV initial cost on the feasibility of the systems and make policy implications. It is recommended to increase the amount of residential PV incentives in Turkey and develop a regional support mechanism, considering solar differences between regions.

Green ammonia production is facing increasing interest on a global scale as a hydrogen carrier for power generation as well as fertilizer for food production. The conventional Haber-Bosch method for ammonia synthesis is energy demanding, requires high purity hydrogen, and is based on fossil fuels. A preliminary techno-economic model for electrochemical ammonia synthesis at near ambient pressure using feed rates of 32 metric ton/day for hydrogen and 135 metric ton/day for nitrogen is presented in this study. Various pathways using different methods for nitrogen generation and hydrogen production were investigated to gain insight into added energy savings per metric ton of ammonia. Electrochemical synthesis using electrolysis for hydrogen and cryogenic nitrogen was found to be a potentially viable pathway for green ammonia. The profitability metrics including discounted cash flow rate of return, net present value and discounted payback period were estimated to be 8%, $40 MM, and 4–6 years respectively for this pathway. The cost of electricity, conversion rate, and conversion efficiency dominate the tonnage cost of ammonia and were used to assess the feasibility of the model. A life cycle assessment was also conducted to assess the environmental impact of a well to product ammonia process.

This paper presents a holistic approach to promote bioenergy in India by designing a conceptual framework that combines resource, technology and market. The proposed concept is an attempt to integrate pelletization and gasification technology for bioenergy system development through an end-to-end approach. The potential of bioenergy resource (i.e. agro waste) was estimated based on survey. The study further assessed the economic feasibility of agro waste pelletization. The economic evaluation was made using indicators such as net present value (NPV), internal rate of return (IRR), discounted payback period (DPBP) etc. Pellet plant capacity of 0.5 ton h−1 showed acceptable economics and the NPV, IRR and DPBP were ₹9.35 million ($0.13 million), 41% and 2.8 years, respectively. Moreover, the larger capacity plants (>2 ton h−1) were subjected to more risk under low pellet prices (

This paper aims to make an investigation on economic analysis of fusion-biomass hybrid system for clean fuel production. A blanket concept with lithium lead (LiPb) and silicon carbide (SiC) technology such as dual coolant lithium lead (DCLL) is capable of delivering over 600 °C of high temperature heat for endothermic gasification reaction. This technical extension enables to produce syngasane gas which converts into either artificial diesel by Fischer-Tropsch reaction or hydrogen by water-gas shift reaction. An experiment has been perform to learn the mass loss and endothermic heat of biomass in the high temperature condition. With the experimental result, levelized cost of fuel (LCOF) was calculated 0.46 $/liter (9.2 $/GJ) for diesel and 1.05 $/kg (8.7 $/GJ) for hydrogen. Also further economic analysis of internal rate of return and discounted payback period was demonstrated for the feasibility of the future deployment.

Sub-Saharan African region currently suffers from the lack of clean energy and heavy postharvest loss. Hence, a biogas driven combined cooling, heating and power generation system that harmonises power generation with food drying and cold storage is studied in the context of current renewable energy policies of the Nigerian government. Wastes from a community cattle market are assessed for biogas generation that is subsequently used to power a 72 kW internal combustion engine. Heat is recovered from the engine to drive a cabinet dryer, an absorption chiller and maintain anaerobic digestion process. The model is developed in Aspen Plus and the results are used to evaluate the economic viability of the system. The electricity and tri-generation efficiencies are 25.7% and 74.5%, respectively. Results also suggest that energy demand of 407 farmers can be met including drying of 12,190 kg of cassava, 3,985 kg of maize and cold-storage of 6,080 kg of tomato per farmer every year. At $0.05·kWh−1 of electricity, the discounted payback period varies between 2.5 and 4.7 years depending on agricultural product processed. Levelised cost of energy and profitability index are also sensitive to both interest rate and plant’s availability which become uneconomical above 9% and below 80%, respectively.

One main obstacle to the implementation of low-temperature district heating is the existing infrastructure along with consumer heating devices that were usually designed for higher operating temperatures. If a DHN is installed for a new urban area, these obstacles can be avoided. This study presents an analysis of alternative heat supply scenarios for the newly developing city subdistrict of Kopli (Tallinn, Estonia). The following scenarios were analysed from economic and environmental aspects: scenario A-connection to the existing DHN (supply/return temperatures 95 °C/55 °C, gas-fired boiler house); scenario B-small local DHN (80 °C/40 °C, small gas-fired boiler house); scenario C-small local LTDHN (60 °C/35 °C, small gas-fired boiler house, integrated large-scale heat pump using seawater as heat source). The results of the study have shown that the primary energy consumption per 1 MWh of heat consumed is 1.33 MWh for scenario A, 1.15 MWh for scenario B, and 0.71 MWh for scenario C. To achieve IRR = 7%, a 4 year discounted payback period was calculated for scenario B, with the NPV of 1.000.000 EUR after the period of 10 years. For scenario C, the payback period is more than 5 years, and the NPV is 2.600.000 EUR after 10 years.

In this study, techno-economic comparison of three different biodiesel production scenarios integrated with glycerol supercritical water reforming (SCWR) process to produce electricity is conducted. In the first scenario, biodiesel is synthesized from acid-pretreated waste cooking oil (WCO) in the presence of alkali catalyst. In the second scenario, biodiesel is obtained from WCO by acid catalyst. In the third scenario, biodiesel is derived from WCO using acid catalyst, followed by hexane extraction of the produced methyl esters. The glycerol evolved from all the above-mentioned pathways is then subjected to the SCWR process in order to produce hydrogen. The produced hydrogen is then combusted to provide thermal energy required by biodiesel production and purification processes as well as to generate electricity. All the developed scenarios are modeled and simulated in Aspen HYSYS software environment. In order to simplify the simulation process, canola-based WCO is considered as triolein with 6 wt% oleic acid (free fatty acid) and, accordingly, the prepared biodiesel is taken into account as methyl oleate. In order to compare the economic profitability of the developed approaches, several economic indicators including net present value (NPV), internal rate of return (IRR), payback period (PBP), discounted payback period (DPBP), and return on investment (ROI) are used. A sensitivity analysis is also carried out to show how variations in feedstock, biodiesel, and electricity prices can affect the NPV of the developed scenarios. According to the results obtained, the highest IRR and ROI values as decision-making parameters are obtained for the first scenario, manifesting its suitability from the techno-economic viewpoint. The economic indicators of the second scenario are also acceptable and very close to the first approach. Overall, upgrading glycerol into hydrogen using SCWR process appears to be an attractive strategy for enhancing the economic viability of biodiesel production plants.

An assessment of the financial attractiveness of using Scheffler dish for solar steam cooking at institutional/community level in India is presented. Three sizes of institutional kitchens, i.e. small (200 persons), medium (500 persons) and large (1000 persons) have been considered. Aperture area of solar energy collection, the investment required and consequently the values of several measures of financial performance for small, medium, and large-sized Scheffler dish based institutional solar steam cooking systems have been estimated. The assessment of the annual amount of steam generation has been carried out at over thirty different locations in the country (capital city of each state of India). The annual amount of steam generated is estimated to vary between 583 and 1072 kg per m2 of the aperture area of the Scheffler dish. As expected, the financial attractiveness of the Scheffler dish based solar steam cooking system changes with the locations. The lowest values of the estimated discounted payback period are 9, 7 and 6 years respectively, for small, medium and large-sized institutional kitchens. Large-sized solar steam cooking systems are financially more attractive essentially due to the economy of scale in the capital cost of these system.

This paper examines the economic viability of a hydroponic system using a distinguished approach to treat investment risk. Risks of the proposed investment project were considered in an investor’s minimum attractiveness rate, in which theoretical models of mature financial markets were adjusted to specificities of emerging markets, such as Brazil. Production costs of a hydroponic farm in Mato Grosso do Sul (Brazil) were searched between July and October 2017. Economic viability of the project was evaluated using the following financial metrics: Net Present Value (NPV), Internal Rate of Return (IRR), Modified Internal Rate of Return (MIRR), Benefit-Cost Ratio (BCR), Cash Generating Index (CGI) and Discounted Payback Period (DPP). An annual interest rate of 9.1060% was used as a Minimum Acceptable Rate of Return (MARR). Sensitivity analysis based on a Monte Carlo simulation was adopted for risk analysis. Initial investment for deploying the project was estimated at $ 89,653.66, with gross annual revenue of $103,903.63. Results of economic viability analysis showed the following financial values: NPV ($ 177,845.74), IRR (30,45%), MIRR (16,81%), EAV ($ 24,856.30), BCR (2,13), CGI (2,29) and DPP (5,24 years). Sensibility analysis identified that NPV is mostly affected by variations in prices received by the farmer. Risk analysis based on Monte Carlo method confirmed economic viability for the investment project proposed in this study.

This study presents the outdoor performance assessment of a 2.5 MW solar-photovoltaic power plant installed at Navrongo, in the northern part of Ghana. The system's hourly energy output and environmental data between June 2013 and May 2016 were collected and analysed. The average yearly energy generated by the installation was 3547.8 MWh, while the performance ratio was found to be 70.4% and levelized cost of energy estimated as US$0.2411/kWh. Using the prevailing exchange rate at the time of commissioning and guaranteed feed-in tariff, the installation's discounted payback period is estimated at 14.95 years. Furthermore, the solar PV power plant project has saved over 3852 metric tons of carbon per year since its installation.

Transplanting of unrooted plant cuttings to produce rooted liner trays is a manufacturing process that requires considerable manual labor. However, increasing labor cost and reduced labor availability has increased interest in automation. The objective was to evaluate return on investment of transplanting robots, and identify key factors that businesses should consider when purchasing a transplanting robot. Data on labor costs, cuttings transplanted, and costs of automated transplanting were surveyed at six greenhouse firms. The resulting average scenario assumed an annual labor cost of $408,377 to manually transplant 29.3 million (M) cuttings at $12.49 per hour, resulting in a cost of $0.014 per cutting. An investment of $125,000 in one transplant robot operated for up to 76 h per week (2 shifts) had an annualized cost of $70,270 ($6,250 cost of ownership and $64,020 labor cost for robot operators). The robot could transplant 7.2 M cuttings per year (25% of the total), at an average cost of $0.010 per cutting compared with $0.014 for manual transplanting. With these assumptions, over 10 years the transplant robot would yield an annual cash flow saving of $29,891 a Net Present Value (NPV) of $105,807 and a discounted payback period of 4.8 years. Each transplant robot would reduce labor requirements during the peak week by two full time equivalent workers (3% of total workforce). Sensitivity analysis showed investment in automatic transplanting was increasingly profitable with a high local wage, and low manual labor efficiency (few cuttings per workers). There were economies of scale when more than one robot was used. Greater efficiency resulted from increasing hours of robot operation during the peak period, and in operations where cuttings were transplanted throughout the year. Results can be used to evaluate the impact of automation on labor cost and availability for the transplant process.

Recently, solar energy is considered as the most promising renewable energy source, due to the availability and advancement of the solar technologies. This paper presents an extensive energy, economic and environmental analysis of 2.04 kWp of polycrystalline (p-Si), 2.04 kWp of monocrystalline (m-Si) and 1.86 kWp of amorphous on microcrystalline (a-Si/μc-Si) identical PV systems installed on the rooftop of 20 different institutional buildings, located in various Moroccan sites. Based on the analysis conducted, annual results are predicted with respect to hourly meteorological data and performance characteristics of each technology are examined using energetic, economic and environmental indexes (3E analysis). Daily simulation results were compared with actual recorded data for one of the geographical site (Meknes city) and good matching between simulated and recorded data has been achieved to prove its validity. The energetic analysis has shown that poly-Si modules surpassed the mono-Si and amorphous-Si modules in terms of performance, capacity factor and conversion efficiency. Besides, economic analysis has been conducted to determine the discounted payback period and levelized cost of electricity (LCOE) for 20 Moroccan cities and the results have shown that p-Si, m-Si and a-Si/μc-Si offered the 20-city average of 17.1, 21.6 and 28.6 years payback period, respectively. Moreover, LCOE has been determined for each city and the results reveal that p-Si, m-Si and a-Si/μc-Si types PV modules presented the average of 9.02, 10.13 and 12.53 cent€/kWh, respectively. Finally, the environmental analysis has revealed that average of 1.316, 1.286 and 1.051 tons of CO2 per kWp can be reduced by adopting the p-Si, m-Si and a-Si/μc-Si PV modules in the studied locations. The findings confirm the potential of the examined technologies and elucidate specific conclusions for the practice of such systems under Morocco’s climate.

In this paper, we report an integrated techno-economic analysis of glycerol steam reforming (GSR) targeting distributed H2 refueling stations for a H2 production capacity of 700 m3 h−1. A process simulation based on mass and energy balances was performed to identify the product yield at effect of temperature and water/glycerol ratio. The results show that temperature of 900 K and a water/glycerol ratio of 9 are optimal to techno-economically operate a GSR process. An economic analysis using itemized cost estimation, sensitivity analysis (SA), and profitability analysis (PA) was carried out to investigate the economic feasibility of GSR for distributed H2 refueling stations. The unit H2 production cost was 4.46 $ kgH2−1 at the optimum conditions identified in the process simulation, and the most influential economic key factor was the reactant from the SA. Meaningful economic indicators such as net present value, discounted payback period, present value ratio, and rate of return on investment were obtained from the PA through a discounted cash flow diagram. Moreover, a cumulative probability analysis based on an uncertainty analysis using a Monte-Carlo simulation method was applied to unit H2 production cost and B/C ratio calculations to quantify the risk of a proposed GSR process as premature technology providing crucial guidelines to decision-makers.

The return on investment in agroforestry depends mainly on meteorological and market variables, both uncontrollable. For this, it is necessary to prepare investment projects to verify the feasibility before executing them, minimizing the risks and uncertainties to the farmer. In this sense, the study aimed to identify the economic and financial viability of a biodiverse agroforestry system to boost income generation and recovery of degraded areas. For this, it was decided to model a biodiverse agroforestry arrangement with the purpose of meeting the new Brazilian Forest Code, Law no. 12,651 of 2012 and promoting economic-financial return to the family farmer in the state of Mato Grosso do Sul. The study method considered the following capital investment valuation techniques: Net Present Value (NPV), Internal Rate of Return (IRR), Equivalent Uniform Annual Worth (EUAW), Discounted Payback Period (DPP), Profitability Index (PI), Modified Internal Rate of Return (MIRR), Benefit Cost Ratio (BCR) and Capital Asset Pricing Model (CAPM). In addition, sensitivity and risk analyzes were developed using Software R (R Development Core Team). There were 10,000 interactions between variables of productivity, price and variable costs. The results demonstrate that the agroforestry system is significantly viable regardless of whether the farmer owns rural property, since net sales revenues can remain higher than the costs over 20 years.

Ground source heat pump (GSHP) system is an efficient solution to mitigate energy consumption and environmental emissions in the building sector. Although the GSHP system is categorized among renewable energy technologies, considering the fact that the system's power demand is usually provided by fossil fuel resources, it may not fully meet this classification. One way to offset the GSHP's electricity consumption in a renewable approach is the use of photovoltaic (PV) panels. This paper aims to study the feasibility of a hybrid PV-GSHP system for a residential building in Tehran, Iran. To that end, a numerical model is developed to explore the GSHP system's performance over a 20-year design life, taking several borehole lengths into account. Moreover, the PV modules are simulated by EnergyPlus software. A life cycle cost analysis is also performed to assess the economic viability and optimal design of the PV-GSHP system. The results illustrate that using four PV modules can best cover the system's electricity consumption and the discounted payback period is less than four years. Furthermore, an environmental evaluation reveals that the PV-GSHP system can save 29.2 t of carbon dioxide emissions over the 20-year period compared to the GSHP system.

The heat treatment followed by polyelectrolyte precipitation is evaluated as an alternate technique for membrane separation-based process for whey protein recovery. The evaluation was conducted on two parameters, quality and techno-economic analysis. The optimum conditions for maximum recovery using combined heat and polyelectrolyte carboxy methyl cellulose (CMC) were determined at lab scale. The quality of the recovered whey protein powder (WPP) was adjudged by determining the functional properties and in-vitro digestibility. The digestibility of the recovered WPP reduced with an increase in heat treatment temperature, with no impact of CMC addition on digestibility observed. The digestibility of WPP recovered at 50 °C was similar to that of commercial whey protein concentrate (CWPC). Although solubility of the recovered protein was lower, but the emulsifying properties were acceptable. For the techno-economic evaluation, a conceptual flowsheet of the thermal-polyelectrolyte precipitation plant was developed and the capital and operating cost was determined. It was found that an integrated whey processing plant producing lactose, in addition to whey protein concentrate was needed to make the project profitable. The NPV of the project came out to be 4.3 million dollars with a discounted payback period of 3.3 years. The risk analysis to quantify the probability of the project being profitable under various deviations from the base case values was done using Monte Carlo simulation. It was found that for the deviation range studied, there is a higher probability of the project being profitable.

The amount of installed solar power in Finland tripled in 2016, reaching 27 MWp. In Finland there are no feed-in tariffs, and with the low price of electricity together with the annual distribution of insolation concentrating on summer, the photovoltaic electricity production is economical only when used for self-consumption. When the produced electricity is used for self-consumption, optimization of the photovoltaic power system size is essential for the profitability of the investment. Usually when optimizing the size of the PV system, the electricity production is optimized so that the electricity sold to the grid is minimized. However, this can lead to undersizing of the PV power system. The PV power system size can for example be dimensioned by using methods such as the minimum energy consumption of the building, the maximum power consumption, or the net zero principle. In Finland, the smart meters provide hourly consumption data from the electricity consumers, which can be used to generate electrical load profiles. These smart meters have been installed on almost every real estate. In this paper, the profitability of a photovoltaic power system in the conditions of southern Finland is studied, simulated, and analyzed for self-consumption. Three cases, a grocery store, a dairy farm, and a domestic house with direct electric space heating, are presented and used in the simulation. Their electricity consumption is measured by hourly automatic meter reading (AMR) on a yearly basis. An Excel tool was used for the analysis of the electrical load profiles against the PV power system production at different system sizes. The profitability of the PV power system was studied by using internal interest rate, net present value, discounted payback period, and self-consumption rate. The effects of government subsidies on the profitability of a PV power system were also examined. The optimized system sizes for the grocery store, dairy farm, and domestic house with direct electric space heating were 89 kWp, 28 kWp, and 5.2 kWp, respectively. The solar modules of the grocery store and the domestic house were facing south whereas the optimal module orientation in the dairy farm was 50–50% east-west. It was found that in the case of the grocery store and the dairy farm, the PV system size could be increased without the internal rate of return decreasing significantly, and thus, a larger system could be justified. Using the self-consumption ratio to optimize the PV power system size leads to undersizing of the system. It was found that the subsidies for the PV power systems have a significant impact on profitability. In the cases of optimized sizes, the grocery store would be economically viable even if the electricity price decreased annually by 3.6% with subsidies and 1.0% without subsidies. The optimized PV power system of the dairy farm would be economically viable if the electricity price decreased by 3.3% annually; however, without subsidies the electricity price would have to increase by 1.0% annually to remain viable. Considering a residential house, the annual increase in electricity price should be 0.6% with subsidies and 1.9% without subsidies. Post-print / Final draft

Dairy industry in India has a substantial demand for process heating at temperatures that can be provided with solar collectors. However, the acceptance and dissemination of solar industrial process heating systems would also be affected by their financial attractiveness for the users. Another attractive feature of SIPH systems is their ability to mitigate environmental emissions. Results of a financial viability analysis including estimation of cost of mitigating carbon emissions with use of SIPH in dairy industry in India are presented in this paper. Seven locations in India with dairy plants have been selected and annual useful thermal energy output of SIPH systems at these locations has been estimated. Further, levelized unit cost of useful thermal energy (LCUTE) delivered by the SIPH systems is estimated and a comparison with the existing process heating options being used in the dairy industry in India have been made. Other measures of financial viability such as discounted payback period, net present value and internal rate of return for an investment in SIPH systems in dairy plants have also been estimated. Finally, the cost of carbon mitigation with use of SIPH in dairy industry in India has been estimated. Results presents that in terms of LCUTE solar industrial of process heating systems doesn’t seems financially viable. Moreover, payback period of the SIPH systems are very higher thus lower value of NPV and IRR, therefore, their use does not seem to be much attractive. Also the cost of carbon emissions likely to be mitigated with use of SIPH is on higher side. Therefore, In view of the long term economic and environmental benefits of using SIPH in dairy industry there is a need of marginal support to ensure their financial viability as compared to fossil fuel based systems, the government may consider providing suitable incentives for the same.

Microgrids are usually powered partially and sometimes fully by small scale distributed generators, renewable energy resources and batteries. The batteries of the electric vehicles (EVs) in a parking deck can also be used as a power source of the microgrids. However, unlike fixed batteries, the storage capacity of a parking deck depends on the number of installed V2G (vehicle to grid) stations and the number of available EVs. In this paper, we propose a mathematical model that aims to determine the optimal number of V2G stations in a microgrid parking deck by minimizing the total cost of investment and operation. The EVs in the parking deck are discharged to shift energy purchases from high-price to low-price hours and vice versa. The uncertainty of the demand and the EVs arrivals and departures and the intermittency of the renewable resources are taken into account. We develop a methodology to compute the operation cost of the system using Benders’ decomposition and search for the optimal number of V2G stations using the Nelder-Mead heuristic algorithm. Numerical experiments are conducted on a 14-bus microgrid test system for a planning horizon of five years. We also assess the effects of uncertainties, EVs battery size, chargers’ rated capacity, EVs arrivals and departure rates, dispatch constraints and interest rate on the determined number of V2G station and the discounted payback period. The experimental results show that investing in the V2G technology can reduce the long-term cost of electricity supply for the microgrid.

In this paper, we report economic feasibility studies focusing on profitability analysis of high pressure polymer electrolyte membrane (PEM) water electrolysis for distributed H2 refueling stations in Korea. From capital and operating costs, a unit H2 production cost of 6.24 $ kgH2−1 was obtained for a H2 capacity of 700 m3 h−1, which is equivalent to handling about 300 fuel cell electric vehicles. Based on cost estimations, profitability analysis using cash flow diagrams was performed to assess the economic feasibility of high pressure PEM water electrolysis and various key economic indicators like net present value (NPV), discounted payback period (DPBP), and present value ratio were obtained for both different discount rates and capacity factors. In conclusion, employment of high pressure PEM water electrolysis was found to be economically profitable showing reasonably high NPVs (16–52 MM$) and short DPBPs (4–7 years).

Techno-economic analysis (TEA) for CO2 reforming of methane in a membrane reactor (MR) was conducted by using process simulation and economic analysis. Parametric studies for key operating conditions like a H2 permeance, a H2O sweep gas flow rate, operating temperature, and a CO2/CH4 ratio were carried out for a conventional packed-bed reactor (PBR) and a MR using Aspen HYSYS®, a commercial process simulator program and some critical design guidelines for a MR in terms of a H2O sweep gas flow rate and a CO2/CH4 ratio were obtained. Further economic analysis based on process simulation results showed about 42% reduction in a unit H2 production cost in a MR (6.48 $ kgH2−1) than a PBR (11.18 $ kgH2−1) mostly due to the elimination of a pressure swing adsorption (PSA) system in a MR. In addition, sensitivity analysis (SA) revealed that reactant price and labor were the most influential economic factors to determine a unit H2 production cost for both a PBR and a MR. Lastly, profitability analysis (PA) from cumulative cash flow diagram (CCFD) in Korea provided positive net present value (NPV) of $443,760∼$240,980, discounted payback period (DPBP) of 3.03–3.18 y, and present value ratio (PVR) of 7.51–4.97 for discount rates from 2 to 10% showing economic feasibility of the use of a MR as simultaneous CO2 utilization and ultra-pure H2 production.

Solar cooling systems are gaining more attention as eco-friendly cooling technology, which could be an alternative to the conventional vapor compression cooling one to meet the growing demand of space cooling. This paper proposes the investigation of different solar cooling systems, namely: solar absorption, solar adsorption, photovoltaic and photovoltaic thermal cooling systems on the basis of performance, economic and environmental aspects. The main objective is to identify the most favorable system depending on climate condition and solar fraction. Moreover, a numerical simulation is performed on EnergyPlus software to determine the cooling loads of a typical office building for air-conditioning purpose. Performance, economic and environmental analyses are carried out in terms of key indicators, such as solar coefficient of performance (SCOP), levelized cost of cooling (LCOC), discounted payback period (DPP), and life cycle climate performance (LCCP). The results showed that the increase of solar fraction impacts positively the economic and environmental indicators, since this could reduce the LCOC, DPP and LCCP values. Besides, the photovoltaic thermal cooling system exhibits the better performance in all climate conditions with SCOP values ranging from 36% to 52%, depending on climate. Furthermore, the economic findings revealed that the lowest values of LCOC are acquired by using photovoltaic cooling system; varying within the range of 0.056–0.25 €/kWhc, depending on climate. While the lowest DPP values are observed in regions with high solar irradiation using photovoltaic cooling system. Moreover, solar adsorption cooling system was found to be the most environmentally-friendly since it exhibits the lowest LCCP value. In addition, it was found that the increase of ambient temperature and solar radiation results in higher SCOP and lower LCOC and DPP values, especially for solar absorption and solar adsorption cooling systems. The current work is expected to serve as a reference for engineers and designers to select the suitable solar cooling system to be installed according to the target location and solar fraction.

The building sector represents a large share of rising global energy demand. Improving energy efficiency in existing building stock is a crucial strategy. Adopting the best energy retrofitting strategy in a specific building is a challenging task due to a plethora of possible combinations of retrofit measures and mutually contrasting objective functions. In addition, peculiar conditions of Iran, such as extremely subsidized energy prices, and step utility tariffs, escalates the challenges of building energy retrofit. Accordingly, the current study presents a simulation-based multi-objective optimization framework characterized by parallel processing structure and results-saving archive. The framework is implemented by integrating MATLAB® as an optimization engine with EnergyPlus as a dynamic energy simulator to minimize primary energy consumption and discounted payback period while maximizing the net present value. The algorithm explores a vast domain of possible solutions including, building envelope, cooling and heating systems, and renewable energy sources. The framework is applied to a single-family residence located in Iran. Three different scenarios are examined with reference to prospective energy pricing policies to evaluate their effect on the attractiveness of energy retrofit projects. For each scenario, final solutions are selected from respective Pareto fronts according to cost-optimality and energy-efficiency criteria and considering budget constraints. The results indicate that even though significant reductions in primary energy consumption can be achieved, implementing energy retrofit under the current energy pricing policy in Iran would not yield economic benefits. However, the elimination of subsidies along with offering incentives for building energy retrofits presents promising outcomes.

This paper presents a rule-based (RB) heating, ventilation, and air-conditioning (HVAC) control system using a multi-layer perceptron network, a deep learning algorithm, for estimating dynamic preconditioning time in residential buildings. The proposed system takes advantage of occupancy, indoor temperature, and weather data to make control decisions in buildings. The system performance is evaluated in terms of financial, demand-side management, energy-efficiency, and occupants’ thermal comfort. The proposed approach considers the perfect occupancy prediction assumption to remove the impact of the uncertainty associated with occupancy prediction and to estimate an upper bound limit for the system performance. The system performance is compared with that of conventional rule-based control approaches to show its effectiveness. To select the optimal control system, the TOPSIS method, as a multi-criteria decision-making approach, is employed. The sensitivity of the proposed system to the temperature setback is also assessed by considering conservative, medium, and deep setback bounds. It is demonstrated that the proposed system outperforms other alternatives when the deep and medium bounds are utilized. This study reveals two limitations of occupancy-based control systems by investigating their performance from financial and peak-demand points of view. First, these systems can cause peak-demand issues and increase the on-peak energy consumption by up to 10%. Secondly, employing a conservative setback can significantly decrease the financial merits of the system, leading to a discounted payback period of 10.87 years for implementing smart thermostats.

Hospital buildings are the main energy users among government facilities which require substantial energy reduction to save its annual operational costs . At the same time, the Ministry of Health Malaysia has set a policy for all hospitals to achieve green building certification, which in line with its global commitment to conserve the environment. Energy efficiency is an important component in every green building rating tool because of its high potential on point scoring. Thus, there is a need to find the most appropriate method to explore energy saving opportunities as much as possible. The overall aim of this article is to evaluate the potential for energy saving in public hospital using a systematic approach. Three methods are applied in this approach which involved energy audit, empirical evidence and simulation works. Energy audit predicts that the chiller system provides the highest energy saving amount of 1,535,175.40 kWh/year (45.54 %) with discounted payback period of 7.15 years. A chiller retrofit measure was implemented as pilot project and the predicted energy savings were validated by empirical evidence. The actual energy saving of 1,688,347.02 kWh/year (50.08 %) was obtained from the chiller system retrofit and slightly higher than what was predicted with discounted payback period of 6.29 years. Apart from active measures, many more energy saving potentials can still be explored through passive strategies. Simulation method is used to establish energy baseline as the basis for predicting energy saving potential for passive strategies that cannot not be measured through energy audit. The combination of these methods is essential to optimize the potential of energy saving through active and passive strategies that have so far has never been implemented in any public hospital in Malaysia.

Roadway lighting was one of the earliest applications for electric lighting technologies. Well-designed roadway lighting offers many benefits and aids the visual tasks of drivers and pedestrians. Currently, the trend of energy management for exterior general lighting has increased in several cities. Generally, high-pressure sodium (HPS) lamps have been the standard throughout Thailand since the 1980s, but the use of HPS lamps has driven high energy consumption. To conserve energy, light emitting diode (LED) street lighting has quickly become a new trend. The primary objective of this paper is to deliver an initial and in-depth assessment of LED technology for roadway lighting applications. This analysis focuses on the performance of LED luminaires compared with the existing standard of HPS cobra-head luminaires in terms of lighting quality, energy savings, power quality, and investment. The analysis is conducted via three components. First, simulation of the roadway lighting quality is performed using the DIALux programme to evaluate and compare with the standard of Thailand. Second, an experimental setup is used to evaluate the energy savings and power quality for cases with and without solar power. Third, the discounted payback period (DPP) criterion and internal rate of return (IRR) are applied to evaluate the investment scenarios. The obtained results conclude that the LED luminaire performs better than the HPS luminaire in terms of power quality and energy savings (energy-efficient index reduction of approximately 40% over the HPS luminaire), which indicates that the utility benefits from use of LED luminaires. However, although the lighting quality results for LED luminaire have values fairly close to that of the standard, the lighting quality should be improved in terms of uniformity. The results obtained from this analysis are expected to help to improve the roadway lighting standard of Thailand in the future.

Manufacturing facilities with large electricity and steam loads commonly meet those loads with a grid and boiler (GB) system configuration. In this study, two alternatives, a natural gas turbine cycle driven combined heat and power (CHP) system configuration and a grid boiler system augmented with photovoltaics (GB-PV), are investigated sustainable manufacturing in reference to the GB system configuration. For this purpose, their discounted payback period (DPP), carbon dioxide (CO2) and nitrogen oxides (NOx) emission reductions, and primary fossil energy impacts are calculated. The major contribution of this study is that it directly compares the application of both CHP and PV technologies at an assumed manufacturing facility in all 50 states of the United States. This highlights the location-specific impacts of the facility. The examined manufacturing facility utility requirements are 5 MW of power and over 12,000 kg/h of 250 kPa and 400 K saturated steam. A DPP of less than 25 years, the technology lifetime, is found in 44 states for the CHP system configuration and 6 states for the GB-PV system configuration. GB-PV and CHP cost-effectively reduce CO2 in 44 and 38 states, respectively. CHP is better for NOx reduction, whereas GB-PV is better for primary fossil energy reduction.

This paper presents the technical design, market penetration, costs, and greenhouse gas emissions of three types of stoves for baking Injera, which is a traditional flat bread and staple food in Ethiopia and Eritrea. The investigated stoves are an improved biomass (Mirt), an electric, and a solar stove. As solar stove, a steam based concentrating high temperature device suitable for indoor cooking, was selected for economic evaluations. Since it is not available on the market yet, material prices and labor costs are considered. After a review of traditional and high temperature solar stoves, a thorough cost analysis is presented. Various economic parameters are quantified, like the discounted payback period for the replacement of a traditional stove by a solar stove. The analysis yields that the levelized cost of useful heat for baking (LCoEuseful) with the Mirt stove is almost 2.5 times as high, and for baking with an electric stove (with domestic electricity prices) it is about 1.1 times as high as baking with the selected solar stove. This is because of fuel costs and very different efficiencies of the stoves. The saving potential of the annual CO2 emissions for substituting all the Mirt and open fire Injera stoves in Ethiopia for solar devices yields about 32.74 million tons. The equivalent CO2 emission reduction from these replacements corresponds to about 22% of the 2010 total CO2e emissions in Ethiopia.

The current work discusses the implementation of grid-connected, residential rooftop photovoltaic (PV) systems under the scenario of low (300 kWh/month), medium (600 kWh/month), and high (2100 kWh/month) electric loads. The analysis shows that, under all load scenarios, using rooftop PV systems with increasing PV ratings increased renewable fraction (by at least 5% for 1 kW PV under high electric load to as much as 89% for 12 kW PV under low electric load) and reduced carbon emission (by at least 5% for 1 kW PV under high electric load to negative carbon emission for 12 kW PV under low electric load). Furthermore, the highest PV rating (12 kW PV) was preferred under low, medium, and high electric loads, with net present cost (NPC) 29%, 72%, and 29% lowered than the respective grid reference systems. Nevertheless, a long discounted payback period was required, especially under low electric load (above 20 yr). A few scenarios with regard to PV module price, PV sellback rate, tariff rate, and carbon tax were therefore analyzed, which led to NPC reductions of 20%, 40%, 40%, and 12%, respectively, for 6 kW PV under low electric load, in addition to shortened discounted payback periods. Although Malaysian data were used for analysis purposes, the current work has worldwide implications, where it serves as a techno-economic model that provides a sustainable development framework for understanding technically and economically the installation of rooftop PV systems for residential households and driving the implementation of rooftop PV installations especially across Southeast Asia.

This work is focused on the evaluation of technical implementations and related techno-economic aspects, the usability of CO2 sources, and possibility of mass deployment of Power-to-Gas technology (P-t-G), with energy storage being the primary objective. For P-t-G, to ensure a low price of surplus electricity is quite necessary. A possible way is to eliminate the regulated electricity distribution fees by associating a methanation plant with the main CO2-producing plant. The methanation plant will then be an auxiliary plant (auxiliary operation) with its own technological consumption and will be exempt from fees. Further, because attractiveness and competitiveness of P-t-G depends on interconnectedness with other technologies, the use of P-t-G as an auxiliary operation of lignite-fired station with nominal capacity of 110 MWhel was evaluated. As a result, the discounted payback period 3.8 (for a discount rate 8%) or 5.1 (for a discount rate 15%) years was calculated. These and other indicators show that the lignite-fired power plant's investment in P-t-G can have a good return.

The anaerobic digestion (AD) process is being increasingly recognised as a technology for clean energy generation. However, in Ecuador, there is a little application of this technology due to lack of adequate research, economic incentives and the current relatively low price of electricity. This study examined the feasibility of biogas production using anaerobic co-digestion of food waste (FW) and primary sludge (PS) under thermophilic (55 ⁰C) and mesophilic (35 ⁰C) conditions. The biogas is then used for power and heat generation. Using case study approach, data were collected from Riobamba vegetable market and Penipe waste treatment plant in Ecuador. Three different mixing ratios of FW: PS were used (1:2, 1:1 and 2:1) with volatile solids (VS) content of 84.53%, 86.99%, and 89.6% respectively. Furthermore, the organic loading rates (OLR) used were 2.08, 2.49 and 3.34 gvs 1-1 day-1 for the above mixing ratios with a hydraulic retention time (HRT) of 21 days. Computational models of biogas production and a combined heat and power (CHP) system were developed using Aspen Plus software. Results indicated that a mixing ratio of 1:2 and mass flow of 132.42 tonnes/day, the maximum specific methane production obtained was 270 and 205 ml CH4/ gVS at thermophilic and mesophilic conditions respectively. The power production with the aforementioned values were 188.42 and 137.79 kW for both thermal conditions. Finally, an economic analysis for both scenarios was carried out using Ecuadorian renewable energy tariffs. A positive NPV values of £147,580 and £186,307 with a discounted payback period of 20.97 and 17.33 years were obtained for both scenarios respectively, assuming that the interest rate was 4.89% and a lifetime of 25 years.

One of the effective measures to save cooling energy in countries with an equatorial climate like Malaysia is through the use of roof thermal insulation. This paper focuses on the economic evaluation of commonly used thermal insulation solutions for a typical hypermarket roof in Malaysia. Eight commonly used thermal insulation systems have been identified and evaluated. In order to find the most cost-effective thermal insulation measure, three types of economic evaluation methods i.e. life-cycle savings, discounted payback period and internal rate of return have been used. All the eight thermal insulation systems were ranked accordingly to these three methods It has been found that insulation system using small bubble aluminium foil ranked first with the highest life-cycle savings, internal rate of return and the shortest payback period. Sensitivity analyses have also been carried out to identify the effects of changes in the key parameters for example cost of capital and lifetime period have on the evaluation results. The analyses show that small bubble aluminium foil is least susceptible to fluctuation of these two parameters relative to other examined insulation materials.

Sugarcane had its participation in the Brazilian energy sector boosted when PROALCOOL was enacted, a program that encourages the production of ethanol fuel made from sugarcane. The ethanol production process generates a residue in large proportions, called vinasse. This study aimed to assess the economic feasibility of using vinasse to produce electricity in an ethanol plant located in the northwestern region of the state of Parana, Brazil. The electricity generated will be consumed by the plant itself, and the sugarcane bagasse, which was used to be burned in a boiler to generate that electricity, will now be sold to other consumers. The study was conducted considering two operating modes. For each operation, it was considered five scenarios, ranging from the most optimistic (highest salesprice per ton of sugarcane bagasse) to the most pessimistic (lowest sales price per ton of sugarcane bagasse). It was calculated the feasibility of the project by using the Internal Rate of Return (IRR), Net Present Value (NPV) and the discounted payback period. All indexes indicated great economic feasibility to project development. It was conducted an NPV sensitivity analysis considering the variation of the sales price of sugarcane bagasse, the quantity sold and the fixed costs involved. It was also carried out a Probability Analysis, using 1000 NPV simulations, considering that the change in the selling price of the bagasse has a normal distribution. The energy production cost for the expected scenario in Operations 1 and 2 were, respectively, US$51.98MWh−1 and US$ 86.64MWh−1.

Energy meteorology is a new discipline whose importance derives from the need for variable, non-dispatchable renewable power generation to be quantified on timescales from decades (resource assessment) down to minutes (“now-casting”). The need for power generation forecasts becomes more apparent as the variable generation fraction increases above a few percent – at this level sudden large changes in generation capacity (“ramp rates”) can affect power quality and even lead to grid instability. For this reason, many jurisdictions worldwide are starting to implement forecasting requirements on solar photovoltaic (PV) plant owners, including China where the national standard GB/T 19964-2012 on “Technical requirements for connecting photovoltaic power stations to power systems” asks for 15-minute to day-ahead forecasts. Failure to do so or inaccurate predictions, i.e. outside of a desired corridor (±10-15%) lead to penalties in form of reduced reimbursements for the provided solar power. PV power output forecasting errors can arise not only from predicting irradiance, but also - and this is widely underestimated - from the conversion of irradiance to actual PV power generation. Additional uncertainties of ~10% during this step are not uncommon. In this paper, the economic value of forecasting is evaluated using a case study from Henan province, China. We show that even minor deviations from the requested forecasting frequency and prediction corridor can result in revenue losses that have direct impact on the financials of the project (i.e., discounted payback period, net-present value and internal rate of return). This will spark a growing need for accurate energy meteorology in the future.

This paper presents an energy conservation measures prioritization process of a residential Australian building. For this purpose, a simulation model of the building has been implemented and validated based on the information from the energy audit report. Further, a preliminary set of potential energy conservation measures has been identified according to specific information collected during the building survey phase. DesignBuilder software has been used as the simulation tool and yearly energy benefits have been quantified for each intervention. Finally, an economic assessment is conducted based on the most common economic tools (net present value, internal rate of return, profitability index and discounted payback period). As a consequence, a final building performance simulation has been conducted in order to properly quantify the potential energy benefit of the whole retrofit intervention. As results, this study highlights how arduous could be, in certain cases, to achieve a cost-effective retrofit intervention and how economic indexes could bring users to exclude a priori certain energy conservation measures during decision-making process even when these interventions are necessary to improve thermal comfort and energy efficiency.

Economic evaluation for water electrolysis compared to steam methane reforming has been carried out in terms of unit hydrogen production cost analysis, sensitivity analysis, and profitability analysis to assess current status of water electrolysis in Korea. For a hydrogen production capacity of 30 Nm3 h−1, the unit hydrogen production cost was 17.99, 16.54, and 20.18 $ kg H2−1 for alkaline water electrolysis (AWE), PEM water electrolysis (PWE), and steam methane reforming (SMR), respectively with 11.24, 10.66, and 11.80 for 100 Nm3 h−1 and 8.12, 7.72, and 7.59 $ kg H2−1 for 300 Nm3 h−1. With sensitivity analysis (SA), the most influential factors on the unit hydrogen production cost depending on the hydrogen production capacity were determined. Lastly, profitability analysis (PA) presented a discounted payback period (DPBP), net present value (NPV), and present value ratio (PVR) for a different discount rate ranging from 2 to 14% and it was found that a discounted cash flow rate of return (DCFROR) was 14.01% from a cash flow diagram obtained for a hydrogen production capacity of 30 Nm3 h−1.

Integrated photovoltaic (PV) and agricultural greenhouses (PVGs) have seen a rapid expansion in recent years in China. However, declining Feed-in Tariffs and underutilization of PV greenhouses also cause public concern regarding their actual economic performance. In this study, we address the economic and social performance of five PVGs based on a case study. The conclusions show that PVGs could achieve a good economic performance. Their Annual Return on Investment (AROI) varies from about 9% to 20% with a discounted payback period of 4–8 years depending on the different crops produced in PV greenhouses. Furthermore, PVGs also bring considerable social benefits, such as providing new jobs, raising taxes and avoiding substantial CO2 emissions. Sensitivity and uncertainty analysis reveals that crop price is the most sensitive influencing factor. The importance of the electricity feed-in tariff is much less than what we expected. This implies that PV agricultural companies should pay more attention to crop planting and that policy-makers should also shift the focus of incentives from PV power generation to agricultural crop production.

Conceptual design for two options of carbon-dioxide-utilized gas-to-methanol process (CGTM) was implemented by using process simulation software Aspen Plus. The overall mass and energy stream results as well as the thermal and carbon efficiency were obtained from the developed process models. Before the following economic evaluation and sensitivity analysis, total capital investment (TCI) and total product cost (TPC) of both CGTM options were determined. Then, economic evaluation were conducted to assess the economic profitability of the base cases for both CGTM options, using the economic evaluation indicators such as net present value (NPV), internal rate of return (IRR), and discounted payback period (DPBP). Furthermore, sensitivity analysis as well as break-even analysis were also applied to investigate the economic performance of both CGTM options under different circumstances, by changing parameters such as methanol and NG prices, plant scale, and carbon tax. It was shown that the methanol price, CAPEX, and NG price are the most sensitive factors, and the two CGTM options were economically feasible in the plant scale range of 2500–5000 ton per day, according to the economic evaluation indicators NPV, IRR, and DPBP, and were more economically competitive in the case of higher plant scale and carbon tax.

The problem of energy use is one of the challenges of modern society. It is connected not only with the generation of harmful emission but also with the use of other associated resources. Energy efficiency in industry is one of the cleanest energy sources due to not generating energy. Current work proposes an approach for reducing primary energy use and harmful emissions at the oil refinery via thermodynamic analysis of process and energy streams and definition of an energy recovery potential. The proposed approach is based on the systematic reduction of energy consumption by an energy audit, a detailed process and units simulation, improved energy recovery and identifying the most reliable and economically viable process changes. It includes the heat and utility exchanger network analysis by grid diagram to find an energy gap and main drawbacks. The case study represents an application of the proposed method at the hydrocracking unit, where a considerable potential for energy efficiency was identified and utilised. The retrofit option was developed to show how debottlenecking and process changes contributes to overall operational efficiency. As a result, the energy consumption was cut by 54% and the economic efficiency of the proposed process changes confirmed by the discounted payback period of 9.5 months, excluding the time for the detailed design, equipment purchase, installation and start-up. Environmental results demonstrate the annual saving of 18,915 tons of carbon dioxide. Due to the slowing down of global economic growth, more attention should be paid to the modernisation of existing process plants. It may speed up the transition to an environmentally friendly economy and help solving global problems.

This article presents a holistic approach to promote waste foundry sand (WFS) reclamation in India by designing a framework for a multistakeholder approach that combines resources, technology, and potential market. The scale of WFS generation and dumping is estimated based on a survey, and a solution is proposed that integrates WFS collection and sand reclamation technology for foundry sand ecosystem development. The study further examined the economic feasibility of a mechanical reclamation process for WFS, using indicators such as net present value (NPV), internal rate of return (IRR), discounted payback period (DPBP), and benefit-cost ratio (BCR). A sand reclamation plant of 1 ton h−1 capacity showed promising economics, and the NPV, IRR, DPBP, and BCR were found to be ₹57.21 million ($0.76 million), 29.78%, 2.82 years, and 5.48, respectively. All the operating, manpower, raw material, and utility costs reasonably influence the economics of the reclamation process. In parallel, sensitivity and uncertainty analyses were carried out using a Monte Carlo simulation to understand the influence of the above-mentioned indicators on the economics of the process. This uncertainty analysis predicted an average NPV of ₹56.55 ± 2 million ($0.75 ± 0.027 million). The castings made up of reclaimed sand appeared to be cost competitive at the reclaimed sand price in the range of ₹1000–2000 ton−1 ($13.33–26.67 ton−1). Overall, the designed framework appears to encourage reduction in WFS disposal and promotion of reclaimed sand in Indian foundries. Policy interventions are suggested to promote the proposed solution in its initial phase.

This paper aims to evaluate the energy-saving potential, affordability and thermal comfort performance of various passive building retrofit measures for a historical building (late nineteenth-century Victorian house) renovation. Three types of interior passive retrofit measures (i.e. internal wall insulation, glazing upgrade and airtightness improvement), classified as traditional and advanced measures, are further grouped into 63 retrofit combinations. In order to evaluate the performance of these defined retrofit combinations, five assessment indicators are proposed, including energy reduction rate, specific initial cost, discounted payback period, space volume reduction rate, and indoor thermal comfort. Under three internal space reduction scenarios with a space reduction rate of 5.2%, 2.6% and 1.3%, these combinations are evaluated and compared, and the most favourable combinations are determined to achieve multiple objectives (maximum energy saving, most cost-effective and most energy-efficient). The influence of the most favourable retrofit combinations on the internal thermal comfort level improvement is also dynamically evaluated using the EnergyPlus simulation tool. The final recommended passive retrofit combination consists of vacuum insulation windows, gypsum air infiltration reduction, and 2 cm thickness of Polyisocyanurate (PIR) panels, with 51.8% of primary energy reduction, a specific initial investment of £144.71/m2 and a discounted payback period of 18 years.

In this paper, a model simulating bio-methanol production through gasification of different woody bioresources (pine biomass, biochar, and pyrolysis oil) is investigated using process simulation software Aspen Plus. The process consists of gasification, syngas post-treatment, methanol synthesis with recycling and purification. The model results are used as inputs in a techno-economic analysis of the process to assess the economic feasibility, as well as a sensitivity analysis to evaluate the impact of key variables. The economic evaluation is conducted by using three indicators, i.e., the net present value (NPV), internal rate of return (IRR), and discounted payback period (DPBP). The sensitivity analysis is achieved to investigate the economic feasibility of different plant scales, changing parameters such as bio-methanol price, feedstock price, total capital investment (TCI), and plant lifespan. The preliminary economic evaluation results revealed that bio-methanol production from biochar can be an attractive option. The IRR obtained in the biochar scenario is greater, compared to using pine biomass. At a minimum plant scale of 1000 tons per day (TPD) and bio-methanol price of 1300$, biochar can achieve an IRR of 5.3%, which is higher than biomass at the same plant scales, although the price of biochar is higher than biomass. The IRR obtained in the pyrolysis oil scenario hardly reaches 5% unless the price considered for bio-methanol is as high as 2500 $/ton at the plant scale of 2000 TPD.

Green roofs (GRs) have several private, environmental, and social benefits, though financial issues have been considered a major barrier to its widespread use. The lack of knowledge and information regarding the value and applicability of each such benefit has resulted in limited adoption of GRs in Malaysia. Hence, the aim of this research is to analyse the financial feasibility of GR installation, considering social and private perspectives (where the applicability of benefits varies across various scenarios). To do that, the applicable short- and long-term costs and benefits of GRs were identified through reviewing the literature. Then, the variables’ values were investigated and calculated using Monte Carlo simulation. GRs’ net present value (NPV) and discounted payback period (DPBP) were analysed in different private scenarios to derive its financial feasibility out in Kuala Lumpur. Additionally, projected social benefits were analysed to indicate the government’s financial benefit from GR adoption. The results showed that NPV for the private sector could be up to $1072.44 m2 and $735.11 m2, while it is most likely around $390.78 m2 and $258 m2 for intensive GR (IGR) and extensive GR (EGR), respectively. Most probably, the DPBP would be between one and nine years and one and six years for IGR and EGR, respectively. Additionally, considering the social benefits of GR, IGR has the potential to offer up to $314 m2; the amount is much lower for EGR at $55 m2. Moreover, it was found that energy saving is the most influential variable affecting NPV in private and social perspectives. Finally, it was concluded that GR installation could be financially feasible if all private benefits are applicable. Since GR has social financial benefits, the initial costs could be partially covered by the government as an incentive for GR installers.

In the present work, the financial viability of three CSP technologies viz. PTC, SPT and LFR for 50 MW, CSP power plants, has been studied for 10 different locations of diverse climate conditions in India. Latest fiscal guidelines laid by the Central Electricity Regulatory Commission (CERC) in 2016 have been followed in the System Advisor Model. Levelized cost of electricity (LCOE), Payback Period (PBP), Discounted Payback Period (DPP), Net Present Value (NPV), and Capital Recovery Factor (CRF) have been estimated to obtain a holistic extensive research view of the CSP projects. The highest NPV is 2626.68, 1311.25, and 827.90 million ₹, and the lowest LCOE calculated is 9.89, 10.63, and 10.99 ₹/kWh for SPT, PTC and LFR. Jodhpur has been identified as the most suitable location for the installation of a CSP plant. A 50 MW Solar Power Tower based CSP plant has LCOE of 9.89 ₹/kWh, PBP of 2.20 years, and NPV of 2626.68 million ₹, which is the best among all selected locations. The findings of this research will help in selecting locations and CSP technology for the installation of power plants. It will also assist investors to understand the financial viability of the project beforehand.

Rapid increase in cost of power, its shortage and impact on environment, compels us to use innovative energy efficient technologies for space heating/cooling. Reduction in power consumption in vapour compression based conventional air-conditioner with air-cooled condenser is a difficult task especially in hot and humid weather conditions (Central region of India), where the summer temperature sometimes exceeds 46 °C. Power consumption of conventional air-conditioner can be reduced substantially by hybridizing it with earth air heat exchanger system. In the present research, an effort has been made to reduce the power consumption of 1.5 TR window air-conditioner by coupling with earth air heat exchanger system in three different arrangements. When entire cold air from earth air heat exchanger system is supplied to cool the air-conditioner’s condenser coil, the power consumption is found to be reduced significantly in hybrid system as compared to conventional 1.5 TR window air-conditioner. The economic analysis techniques i.e. simple payback period, discounted payback period, net present value and internal rate of return validate that proposed hybrid arrangements are economically viable.

City gate stations receive high pressure natural gas and decrease the pressure by throttle valves. Concurrent with the natural gas pressure reduction, the temperature also drops. Thus, to prevent blocking of the downstream pipeline by the liquid and solid particles, natural gas must be preheated before pressure reduction. Heaters utilized for preheating task, have a low thermal efficiency and consume a large amount of fuel. In addition to the high fuel consumption, they release a huge amount of CO2 into the atmosphere. Therefore, the present study proposes a new system for in-situ fuel consumption elimination at these stations. It utilizes vertical ground-coupled heat pump system as a renewable source of energy to preheat natural gas stream. The system performance was studied at two different climatic conditions of Iran which have also two different natural gas compositions. Results show that the system is completely capable to eliminate in-situ fuel consumption of city gate stations; however, by considering indirect fuel consumption of electrical heat pumps, the system fuel consumption reduction potential was calculated over 65%. It is also able to reduce CO2 emission up to 79%. The discounted payback period is computed around two years, which proves the suitability of offered system.

Conceptually, hybrid photovoltaic/thermal (PV/T) system is superior to conventional side-by-side photovoltaic (PV) and solar thermal (ST) system due to the increase of energy output per unit collector coverage area. The current study aims to demonstrate the advantages of applying a liquid-based PV/T system over a side-by-side system in a real office scale building to support its electricity and hot water demand via computer program simulations of the explicit dynamic PV, ST and PV/T system models. Second, an economic analysis considering the time value of money is presented to evaluate the viability of installing a solar collector system with the adoption of PV/T instead of the side-by-side option. The discounted payback period, which has considered the maintenance and parts replacement costs, of the PV/T system design option is found to be encouraging. The sensitivity analysis shows that even under large variations of different factors in the calculation model, positive net present value is dominant in most cases within the analysis time period. The study reflects desirable potential of incorporating of PV/T technologies in real office buildings under subtropical climate region like Hong Kong.

Structural insulation panels (SIPs) are considered promising building products that achieve the low-energy goal, and its potential energy performance can be further improved by combining it with a vacuum insulation panel (VIP) in cold climates. The aim of this study is to determine the optimal SIP with VIP (VIP–SIP) thickness and to minimize the energy cost. We conduct a VIP-SIP thickness optimization and cost analysis for five cold sub-regions using P 1 - P 2 methods. First, we develop an energy model using the building energy simulation software OpenStudio considering the VIP aging effect, and the accuracy of this model is validated using field test data. Results indicate that as climates become colder from Cold area B to Severe Cold area A, the optimal VIP thickness increases from 3.5 mm to 31 mm, whereas the optimal PU thickness decreases from 66.875 mm to 174.2 mm. In addition, the total cost saving rate increases from 40.5% to 47.9%, and the discounted payback period decreases from 12.59 years to 8.98 years, indicating improved economic feasibility. Furthermore, the influence of the P 1 value and VIP price on the optimal thickness and total cost are also discussed. The findings of this study confirm the economic feasibility of combining SIP with VIP in cold areas, and provide feasible parameters for the design of low-energy buildings in cold areas of China.

This work investigates the techno-economic aspects of high-temperature heat pumps used for waste heat recovery. The heat pump produces heat at a temperature up to 150 °C from heat of below 100 °C based on both single- and two-stage cycles, with the aim of identifying the most cost-effective among various heat sink and heat source temperatures. Refrigerants with low-global warming potential are considered and a validated heat pump model is used to calculate the cycle performance. Then, the equipment cost of the different configurations is calculated as a function of the component parameters and system scale. This approach provides a trade-off between high efficiency versus high cost, in order to identify the most cost-effective configuration at each temperature level. The results show that the specific equipment cost of the heat pump is usually in the range of 150 to 300 EUR/kW, mostly depending on the cycle design and temperature. Moreover, the discounted payback period of industrial installations shows a large scatter, and can even be as short as 3 to 4 years. The overall outcome is that the single-stage cycle with an internal heat exchanger is favoured in terms of economic performance, except with large temperature lifts of over 50 K, in which a two-stage cycle shows superior cost-effectiveness.