Economic Payback Period Research Articles

Predicting the economic feasibility of solar-based net-zero emission buildings (NZEBs) in the United States non-residential sector

Buildings have significantly contributed to high energy demand (30.3%) and GHG emissions (26.1%) worldwide. Consequently, many developed countries have set carbon-neutral targets for 2050, mandating that all new constructions thereafter be designed as net-zero emission buildings (NZEBs). To achieve this goal, one of the most practical sources of renewable energy, solar power, is employed in this study to estimate the economic feasibility of implementing NZEBs in the non-residential sector of the United States. While past studies have typically estimated the economic payback period of solar power technology by assuming fixed values for “PV energy conversion rates (%)” and “investment costs ($USD)”, this paper carefully investigated the economic feasibility of “solar-based NZEBs” by precisely tracking these dynamic future changes in PV panels. These techno-economic variables were carefully predicted using a statistical technique known as the five-parameter logistic (5 PL) function. The results show that Site 4 is the only solar region suitable for implementing “PV-integrated NZEBs”, reaching a payback period of 8.44 years in 2040 (Scenario 1). Furthermore, with small technological improvements in PV energy efficiency (%), buildings located in Site 3 and Site 4 can meet the net-zero emission target with payback periods of less than 10 years in 2034 (Scenario 2). Finally, starting in 2044, the “PV-integrated system” will have a payback period of approximately 7 years in most study locations, even without federal support for the solar investment tax credit (SITC). Accordingly, federal support for solar power generation will be more effective if the SITC rate is gradually reduced by 2.5% annually starting in 2033. In conclusion, this paper suggests the economic feasibility of implementing solar-based NZEBs in the United States non-residential sector by considering the synergetic effect of technological improvement and cost reduction in PV-integrated systems.

Machine learning, mathematical modeling and 4E (energy, exergy, environmental, and economic) analysis of an indirect solar dryer for drying sweet potato

A developed indirect solar dryer is built and operated to dry sweet potato cubes. Since, numerous instruments have gathered experimental data to comprehensively evaluate the system's energy, exergy, environmental, and economical aspects. Additionally, four machine learning algorithms, namely Decision Trees (DT), Gradient Boosting Regression (GBR), Multiple Linear Regression (MLR), and Random Forest (RF), are evolved to forecast the solar collector's energy (RSAH,η) and exergy efficiency (RSAH,ηEX) as well as the drying chamber's mean drying temperature and exergy efficiency (DC,ηEx). In addition, ten drying kinetics mathematical models were employed to fit with sweet potato moisture ratio variation over the experiment. Also, Color and bioactive compounds were analyzed. Results show that, RSAH,η and RSAH,ηEX was 72.9 %, and 5.6 %, respectively. Storage unit thermal (ηTh.,SUPCM)and exergy efficiency (ηEx,SUPCM) were 43.4 %, and 18.4 %, respectively, the discharging lasted around 5.5 h. Theoretical drying chamber thermal efficiency (DC,ηth) was from 21.9 to 97.2 %. And av. DC,ηEx was 46.1 %. RF algorithm achieved the best results for RSAH,η, RSAH,ηEX , DC,Tmean, and DC,ηEx forecasting, because of its superior adaptability and generalization. The overall dryer efficiency was 15 % with a specific energy consumption of 4.509 kWh/kg moisture. The Page model showed the best fitting with sweet potato moisture ratio data. In addition, CO2 mitigation reached 20.2 with earned carbon credit is 56771 RMB. The economic payback period is 29.24 months, the annual total revenue is 8464 RMB and 0.7 RMB as a Return on investment.

A multi-scale lifecycle and technoeconomic framework for higher education fleet electrification

Transportation accounts for one-quarter of all energy related greenhouse gas emissions. As it pertains to transport electrification, higher education institutions—such as universities—can model solutions that affect broader society. Despite this, higher education’s role in fleet electrification adoption has been understudied. We, therefore, modeled an archetypical higher education institution to analyze the carbon and economic payback periods of three electrification scenarios (Business-as-Usual, Targeted Electrification, and Full Electrification) using a cradle-to-grave lifecycle and technoeconomic approach. Given the archetypical higher education institution fleet of 368 vehicles, results show an economic ratio plateau point of about 8 years at 20 fuel-based cars replaced by electric vehicles and a carbon payback period peak of roughly 10 months at 50 fuel-based cars replaced. We then performed a multi-scalar analysis by leveraging implementation theory. We find that higher education institutions that adhere to the tenets of implementation theory are poised to be pro-environmental change agents in many regions and countries. The methods and findings herein can be adapted to other institutions, regardless of fleet size, and can bolster relevant decision-making outcomes now.

Effects of external reflector and glass cover cooling on thermo‐enviro‐economic performance of a stepped solar still

AbstractIn the current research work, performance enhancement of stepped solar still (SSS) having an external reflector (ER) and glass cover cooling (GCC) arrangements is presented. The individual and combined effects of ER and GCC on the performance of SSS have been evaluated and compared with simple SSS. The GCC reduces the glazing temperature significantly and results in increased distillate. The ER reflected the solar radiation inside the basin that increases the water temperature, consequently increasing distillate. The SSS having ER and GCC (SSS‐ER‐GCC) gave a maximum distillate of 4.340 kg/m2 which was observed, respectively, 12.43%, 3.21%, and 1.36% higher than that of simple SSS, SSS with ER (SSS‐ER) and SSS with GCC (SSS‐GCC). The average energy efficiency of SSS‐ER‐GCC was evaluated as 40.78%, which was found to be 14.36%, 7.84%, and 10.64%, respectively, higher than that of simple SSS, SSS‐ER, and SSS‐GCC. The carbon credits earned and CO2 mitigation were found the maximum for SSS‐ER‐GCC having values $65.96 and 4.40 tons, respectively. The economic payback period was found the minimum (490 days) for SSS‐ER‐GCC.

Evaluating the environ-economic and exergy-energy impacts of drying carrots in passive and active mode solar dryers

On the basis of exergy-energy and economic-environmental (4E) parameters, passive and active indirect solar dryers (PISD and AISD) were analysed and compared by drying carrot slabs. The PISD dryer was upgraded using fans run by photovoltaic panels those were placed at the gate of a divergent duct to make an AISD setup. Experimentally measured primary parameters were used to evaluate the 4E parameters. Accordingly, AISD had enhancement in collector and drying efficiencies of 19.27 and 11.86% than PISD, respectively. Specific energy consumption (32.2%) and moisture extraction rate (47.17%) were better for AISD than PISD. Both setups were examined for their exergy parameters (mean efficiency, outflow, loss, and inflow). Exergy and environmental stability indicators such as sustainability index, environmental factor, waste exergy and improvement potential were calculated and distinguished for both dryers. AISD dryer gave better CO2 mitigation and carbon credit than PISD. The payback period of energy over 30 years lifespan was 1.33 and 1.78 years, and the economic payback period was 1.02 and 0.622 years, for PISD and AISD respectively. In comparison with PISD, the AISD achieved better in all the evaluated parameters. An uncertainty study was carried out for all the measured and estimated criteria. Results were compared with existing studies.

Numerical analysis of solar ventilated façade integrated thermoelectric energy harvesting panel for simultaneous building thermal insulation and power generation

Although coupled thermal and power analysis has been conducted on many existing solar ventilated façade system, there is still a challenge and considerable problem on the synergistic enhancement of power generation and thermal insulation using solar energy. Motivated by this, this study proposed a novel solar ventilated façade integrated thermoelectric energy harvesting panel (SVF-TEHP) using computational fluid dynamics (CFD) simulation to produce renewable electricity and augment thermal resistance by implementing solar active thermoelectric power generation and passive ventilation strategies. Firstly, a coupled simulation model jointly with heat transfer process, energy and exergy analysis were presented to explore the effect of key parameters on thermal insulation performance and electrical performance of the SVF-TEHP, such as solar intensity, channel height, channel width and length of thermoelectric arm. Furthermore, a comparison of the system performance of SVF-TEHP, solar ventilated façade (SVF) wall and conventional wall (CW) was made from the viewpoint of building cooling and solar thermoelectric generation. Finally, the economic payback period, carbon emissions and solar utilization limit were addressed to predict the application potential and challenge of the SVF-TEHP as functional enclosure structure for building energy saving. The comparisons of SVF-TEHP, SVF and CW show that interior wall temperature can be decreased by 8.5 K and 16.5 K for solar intensity of 900 W/m2, and the output power of SVF-TEHP can reach 0.37 mW. Alternatively, the detailed analysis performed that there is a positive correlation between power generation and thermal insulation performance and the shortest payback period of this system can reaches less than 1 year. This paper will provide a lot of useful information for understanding thermal insulation and energy conversion of solar buildings.

Synergies between China's Whole County photovoltaic program and rural heat pump adoption

AbstractElectrification of heating, particularly with highly‐efficient heat pumps, is increasingly viewed as essential for reaching the targets of the Paris Climate Agreement. China has promoted replacement of dirty coal heating in rural areas. More recently China has also begun promoting distributed solar photovoltaic (PV) energy as a rural development strategy, particularly with the launch of the Whole County PV pilot program in 2021. While several studies have examined the economics of heat pump adoption, with or without solar PV, the Whole County PV program has not been specifically studied. Further, many prior studies utilize monthly average solar production or temperature ranges. This study examines the economics of heat pumps in participating counties in the Whole County PV program, employing hourly data for both PV output and ambient temperature in participating counties. The analysis shows that pairing residential heat pumps with PV in counties in Shandong, Henan, and Jiangsu would result in short economic payback periods versus gas or resistance heat, while also increasing self‐consumption of PV. The results suggest that expanding the Whole County PV program to incorporate energy efficiency and heating/cooling measures represents an economically attractive way to accelerate the rural energy transition and improve rural livelihoods. Such a policy would help accelerate the low‐carbon energy transition, reduce air pollutant emissions, and help address oversupply of midday PV output in local areas. Barriers to the approach include involvement of different government ministries, the cost of upgrading building insulation, the design of building codes, and the structure of electricity tariffs.This article is categorized under: Sustainable Energy > Solar Energy Energy and Power Systems > Electrification Cities and Transportation > Buildings

Economics and lifecycle carbon assessment of coconut oil as an alternative to paraffin phase change materials in North America

Globally, almost 40% of carbon emissions are attributable to building operation and embodied carbon. Phase change materials (PCMs) can store solar energy during peak periods to decrease summer cooling loads and overnight winter heating loads and emissions. At present, most PCMs are non-renewable paraffins with high embodied carbon; plant-based oils such as coconut oil may maintain the conditioning load reductions, while reducing the sustainability and embodied carbon of PCMs. The objective of this study was to determine the economic and emissions of coconut oil as an alternative to paraffins via full house simulations in three North American locations within different climate zones. It was found that paraffin PCM had greater embodied carbon and annual heating and cooling reductions than the coconut oil, causing the lifecycle carbon footprint to be lower with paraffin PCM than with the coconut oil over the house lifetime. This indicates the importance of developing bio-based PCMs with latent heat capacity that more closely compare to paraffins, in order to minimize total building carbon footprint. It was also found that the economic payback period of both PCMs may exceed the lifetime of the house and thus render the PCMs infeasible without reductions in capital costs or increased carbon pricing.

Thermal performance study of a PV-driven innovative solar dryer with and without sensible heat storage for drying of Garcinia Pedunculata.

Uneven drying is the key drawback of a conventional multi-tray dryer. Therefore, an improved active solar dryer with and without integrated sensible heat storage (SHS) was proposed. A unique feature of this dryer is its movable walls from the sides of the dryer to transform it to an indirect or mixed-mode as and when necessary. Garcinia Pedunculata (GP) is a local seasonal medicinal fruit in Northeast India. Drying kinetics of GP, the dryer performance and economic analysis of dryer were evaluated in the indirect solar dryer without SHS (Exp. I), mixed-mode solar dryer without SHS (Exp. II), indirect solar dryer with SHS (Exp. III), mixed-mode solar dryer with SHS (Exp. IV), and open sun drying (OSD). The dryer's average efficiencies were 18.12%, 22.37%, 21.74%, and 24.46% for Exp. I, Exp. II, Exp. III, and Exp. IV, respectively. The moisture content of GP was reduced to 12.09% in wet basis (w.b.) from 87.99% (w.b.). The overall drying time for Exp. I, Exp. II, OSD, Exp. III and Exp. IV were 31, 26, 53, 28, and 10h, respectively. From the eleven drying models, the Two-Term model was the best-fitted model for Exp. I, Exp. II, OSD and Exp. III, and Midilli and Kucuk model was for Exp. IV. The final product's fragrance and colour are better for Exp. IV. Developing this dryer for Exp. I, Exp. II, Exp. III and Exp. IV, the price required was around 25,000, 27,000, 26,000, and 28,000 INR (1 US$ = 74.57 INR), respectively, while the economic payback periods are 1.6years, 0.9year, 1.4years, and 0.59year, respectively.

Adaptable pathway to net zero carbon: A case study for Techno-Economic & Environmental assessment of Rooftop Solar PV System

Several countries have a critical need to enhance their electricity production to satisfy the tremendously increasing energy demand and to minimize the black outs. Due to scarcity of fossil fuels and degrading environment, rooftop Solar Photovoltaic (SPV) can be a suitable renewable alternative of green and clean energy. In this paper, due to the techno-economic, environmental and social benefits of Solar PV, the modelling and planning of a solar PV plant to fulfil the energy demand of an academic building is carried out. The analysis is done including all the financial and environmental aspects considering recent market prices and future price escalation. A Modified Greedy Search based optimal planning of the SPV to minimize grid dependence considering load variation pattern with its assessment analysis for an academic building is proposed in this research work. The various financial parameters that affect the feasibility of Solar PV plant i.e., energy payback period, grid dependency, rate of investment return, economic payback period, rate of escalation with actual cost of electricity, annual maintenance cost, depreciation and taxation are considered and evaluated. The environmental factors related to the generation from Solar PV i.e., CO2 emission reduction and carbon credit are also included in analysis. The results obtained for the proposed Solar PV plant shows that the energy payback period is 8 years and IRR with depreciation and taxation is 21% (approx.) with net CO2 mitigation of 1199 tCO2 during the useful life span (25 years) of the plant.

Performance modeling and analysis of a PVT-HP system with the roll-bond plate as the evaporator during winter conditions

In recent years, PVT (Photovoltaic thermal) has attracted extensive attention in social production and daily lives. As a new technology with low-carbon output, environmental protection and energy saving features, the development of PVT will have great application prospects. Buildings need heating in winter, air-conditioning in summer, and, electricity and domestic hot water supply throughout the year. In the face of the diversified energy supply needs of buildings, the existing photothermal and photovoltaic technologies (irrespective of the photoelectric or photothermal conversion efficiency of modules, or the form of single-function module structures and solar energy utilization systems) are unable to meet the requirements of various energy uses of buildings. There are issues too, such as the large footprint of modules. To this end, this paper starts from the perspective of further improving the comprehensive utilization efficiency of solar energy and meeting the requirements of various energy uses in buildings. The authors adopted a combination of experiment and simulation to evaluate the performance of the PVT-HP (Heat pump) system in this study. The PVT-HP system is set up in Dalian and only runs for a short period of time to get necessary operation data. The simulation model uses a self-built PVT module and verifies its accuracy of the model through its operation date. With the proven PVT-HP model, the authors carried out a dynamic simulation and an economic analysis of the operation of the PVT-HP in winter. The operation performance, supply and demand matching, cost and economic payback period of the PVT-HP system were calculated, and the adaptability analysis for different regions are given. Finally, the nominal power of the PVT-HP system was found to be about 2.4 kW per group, the coefficient of performance (COP) in winter was about 4.32, the total winter heating capacity of the system in Dalian reached 6016 MJ, and the power production reached 168 kWh (which can offset 43 % of the total winter power consumption). The system heating performance was good for all regions, and its payback period in Dalian was found to be 6.53 years; the regional adaptability and economy were found to be ideal.

Passive energy-saving buildings realized by the combination of transparent heat-shielding glass and energy storage cement

Transparent heat-shielding (THS) glass based on selective absorbing materials has great application prospects in reducing building energy consumption. However, the heat generated by absorbing near-infrared light will also increase the indoor temperature, meanwhile, a single energy-saving material often causes obvious indoor temperature differences. This paper presents an energy-saving building room based on CsxWO3@TiO2 coated glass (CG) and polyethylene glycol (PEG)/halloysite nanotubes (HNTs) energy storage cement (CP/F). The CsxWO3 (CWO) nanoparticles coating with TiO2 enhanced the stability of THS materials. The PEG/HNTs energy storage material exhibits a desirable phase change temperature of 28.70 °C, and relatively high latent heat of 74.84 J/g. The test room result shows that the combination of CG and CP/F can reduce the room temperature by about 10 °C, which is greater than the sum of CG and CP working alone owing to the synergistic effect of two materials, that is, CP/F can absorb part of the heat from CG. The combination of CG and CP/F made the indoor temperature distribution more uniform, with the maximum temperature difference decreasing from 6.7 °C to 3.1 °C. The annual energy saving of CP/F-CG in Changsha and Hong Kong is 14.7 % and 23.4 % respectively, and the economic payback period is 6.57 and 4.82 years respectively. The experimental results provide a new perspective on the development of energy-saving buildings.

Transient thermal modeling and performance analysis of photovoltaic panels

AbstractPhotovoltaic technology enables the direct conversion of solar energy into electrical energy. Model studies have a very crucial place in the implementation of PV systems. Electrical efficiency decreases with increasing PV panel temperature. So, solar panel temperature is an important parameter that needs to be reduced to obtain a better energy efficiency from PV panels. In this study, the aim is to develop a simple method that can estimate the temperature of a solar panel. It can utilize different methods to obtain the thermal responses of a PV panel. In this study, a modeling study was carried out to find panel temperature, efficiency and power values under transient ambient conditions. As a simpler approach, “lumped system analysis” method was used. The model developed in this study can simulate the thermal performance of the PV panel under transient conditions. After the model is defined for a particular PV panel, the required inputs are; total incident solar radiation, wind speed and ambient temperature. The results obtained from this model were compared with existing modeling and experimental studies in the literature. With the simulation using the model developed in this study, panel efficiency, temperature and panel electricity power were calculated using instantaneous environmental data for the selected Konya and Sanliurfa (Turkey) regions. In this paper, it was obtained that the wind speed increased the PV panel efficiency, while the ambient temperature decreased it. Depending on the increase in wind speed (1–2 m/s), the increase in PV panel electric power is 3.7%, while the increase in high wind speeds (5–6 m/s) decreases to 0.77%. It was found that a 7°C increase in ambient temperature caused a 4°C increase in PV panel temperature and a 1.5% decrease in PV electrical power generation.The PV panel electrical power values calculated using the efficiency values calculated according to the daily average environmental temperatures were found to be 13% higher than the power values calculated using instantaneous environmental temperatures. If this difference is not taken into account in the calculation of economic payback periods, it will lead to significant erroneous results. The importance of transient simulations of the PV panel has been demonstrated by the calculations.

Uncertainty in Capital Budgeting: Five Particular Safety‐(or Danger‐) Margins from the NPV Formula

The primary approaches for evaluating prospective capital projects, which are investments (outlays) with future financial benefits, are net present value (NPV) and the internal rate of return (IRR), both based on the discounted expected positive and negative cash flows. The NPV formula can be used to provide three additional insights into the evaluation of prospective investment opportunities: normal profit, economic (discounted) payback (or breakeven) period, and maximum investment cost.A review of over two centuries of discussion of capital budgeting techniques reveals no discussion of two alternative approaches and little discussion of a third. This note explores the evolution of capital budgeting techniques, and explains with examples these variations of the NPV formula as additional approaches to evaluating inherently uncertain investment decisions. The formula can be used to calculate “safety‐margins” (also “danger‐margins”) in evaluating potential investments.

Investigation of exergy-energy and environ-economic performance parameters of active indirect solar dryer for pineapple drying without and with energy storage unit

The quality, quantity and availability of energy, the environmental impact, and the economic importance (4E) of a forced convection indirect solar dryer without (setup-1) and with thermal energy storage (TES) system (setup-2) were analyzed during the drying pineapple. Once the tests were finished in setup-1, setup-2 was adopted by integrating with a system having paraffin as a TES unit. The temperature, velocity, and mass data were recorded to evaluate the 4E parameters. The collector and drying efficiency for setup-1 and setup-2 were 67.04, 66.97 % and 7.23, 10.84 %, respectively. Setup-2 was better in activation energy and specific energy consumption. The average exergy efficiency of collector and dryer for setup-1 and setup-2 were 2.33 and 2.12 % and 34.66 and 57.07 %, respectively. Other exergy parameters like inflow, outflow, and loss for collector and dryer and sustainability indicators like waste energy ratio, improvement potential, the environmental impact factor, and sustainability index were enhanced in setup-2. CO2 emission, mitigation, and credit were improved in setup-2. The energy payback period for setup-1 and setup-2 was 1.503 and 1.831 years, while the corresponding economic payback period was 1.41 and 0.93 years in 35 years, respectively. Setup-2 performed better than setup-1 based on the estimated parameters.

Research on indirect cooling for photovoltaic panels based on radiative cooling

Radiative cooling (RC) is a passive cooling technology that has been used to cool photovoltaic (PV) panels since it does not consume energy or produce pollution. Previous studies employed RC materials above the PV panels to directly enhance the thermal emission, thereby lowering the temperature, but this method interfered with the absorption of the sunlight simultaneously, and thus reduced the power conversion efficiency (PCE). In this paper, an indirect cooling system for PV panels based on RC was proposed, consisting of the PV module, RC module, cold storage module, and piping system. The RC module was arranged between the adjacent PV panels, and the generated cold energy was used to cool the PV panels through the water system. Experimental results showed that the system without cold storage module reduced the average temperature of PV panels by 13.6 °C and 10.6 °C respectively in summer and autumn, and increased the PCE by 1.21% and 0.96%, respectively. After employing the cold storage, the cold energy generated at night by the RC module was stored for daytime use, then the average temperature of PV panels was reduced by 17.8 °C and 16.6 °C in summer and autumn, and the PCE was increased by 1.69% and 1.51%, respectively. Moreover, a cover shield and large water tank capacity could further improve the system efficiency. In addition, the proposed system has an economic payback period of 8 years and is expected to increase at least 2.8 billion kWh of PV power generation in 2050.

Application of concatenated stepped solar still system (CS4) for RO-waste-water purification: an experimental study.

This experimental study investigates the capability of a concatenated stepped solar still system (CS4) for RO-waste-water purification by assessing its thermo-enviro-economic aspects. In order to confirm the supremacy of CS4, a simple stepped solar still system (S5) of equivalent basin area (0.75 m2) is fabricated and tested. The experiments are conducted on CS4 and S5 simultaneously at different flow rates for comparison. The productivity of CS4 is observed to be 24.7 % higher than that of S5; thus, its pollutant removal efficiency is better. As compared to S5, CS4 is found to be more sustainable, economical, and better in terms of distillate production and thermal and exergy efficiencies which are optimum at 50 ml/min. The distillate production, thermal efficiency, and exergy efficiency of CS4 at 50 ml/min flow of RO-waste-water are 2.8 kg/day, 33.80%, and 1.93%, respectively. The second and third units in CS4 work in active mode that increases the solar energy utilization by 34.19% at optimal flow rate. The CO2 mitigation capability of CS4 is 8.89 tons and its distillate production cost is $0.021. At optimum flow rate, its energy and economic payback periods are evaluated as 199 and 483 days, respectively.

A Study on Optimum Insulation Thickness in Walls of Chinese Solar Greenhouse for Energy Saving

Chinese solar greenhouses (CSGs) are characterized by unique walls to reduce the transmission of heat and promote the energy conservation in winter production, which promotes cultivation in the northeast region of China in winter. Effective selection of insulation material is important for the CSG based on the energy consumption and economic analysis. However, choosing the thickness of the insulation material in walls often discussed with the structure of CSG. There is a lack of research combing the optimal insulation thickness for improving the energy conservation. The aim of this study was to find the optimum insulation thickness during the energy conservation based on the structure of walls, the energy consumption in local climatic conditions, the cost of insulation material, and economic payback period over a lifetime. By the economic analysis of insulation thickness, thermal resistance, lifetime energy saving, and payback period, three kinds of typical walls (clay brick (CB), hollow concrete block (HCB) and fly ash block (FAB)) combed with four insulation materials including the expanded polystyrene, the foamed PVC, the perlite, and the rock wool were calculated. The optimum insulation thickness can be found when energy savings reached the maximum. In the northeast region, the association of FAB with rock wool as the insulation layer was the most economic composite wall structure. The optimum insulation thickness was 0.05 m, with the cost only 5 USD/m2. The thermal resistance of composite wall had a significant effect on the payback period. When thermal resistance increased from 0.2 to 1.2 m2K/W, the payback period varied from 0.4 to 4.3 years. What is more, the energy consumption in local climatic conditions had a more significant effect on payback period. It can be assumed that insulation materials are more favored in cold climatic regions where heating degree-days over 1600 °C days for payback periods is less than 2 years. These results have strong practical and economical significance in saving energy and improving the environment of CSG.

Techno-economic analysis of furfural purification process from hydrothermal hydrolysis products of oil palm empty fruit bunches using distillation and extraction methods

Furfural is a high-selling compound produced from cellulose and hemicellulose conversion, and the level of demand in Indonesia is still high. This research examines the economic process design and calculation of furfural production made from TKS by varying the purification method with the distillation method and the toluene extraction method using SuperPro Designer 9.5 software. Furfural purification uses two methods, namely furfural purification using toluene extraction scheme and distillation scheme. Two plant location recommendations can be chosen based on the factory’s location close to the buyer, namely in Cilacap, and the plant’s location close to the supplier, namely Banten. Based on the economic calculation results, the toluene extraction purification scheme with an IRR value of 26.02% is more profitable even though its purity is 99.95% compared to the distillation purification scheme with an IRR of 25.86% even though its purity reaches 99.96%. The two recommendations for the location of the calculation of the economic payback period owned by the two locations almost the same. Cilacap, which has an NPV value of 89,739,000 $, is more profitable than Banten, which has an NPV value of 87,430,000 $.

Reduce aviation’s greenhouse gas emissions through immediately feasible and affordable gate electrification

Aircraft at airport gates require power and air conditioning, provided by fossil fuel-combusting equipment, to maintain functionality and thermal comfort. We estimate the life-cycle greenhouse gas (GHG) emissions and economic implications from electrifying gate operations for 2354 commercial-traffic airports in the world. Here we show that complete electrification could yield GHG reductions of 63%–97% per gate operation relative to current practice, with greater reductions correlated with low-carbon electricity. Economic payback periods average just 1–2 years. Shifting to complete gate electrification could save a high-traffic airport an average of $5–6 million in annual climate economic damages relative to estimates of current practice. 10–12 million metric tons of annual GHG emissions are potentially saved if most airports in the world electrified gate operations, costing the 24 busiest global airports on average $25–30, U.S. airports $60–70, and non-U.S. airports $80–90 per metric ton of CO2 mitigated, in some cases comparable to carbon-market prices. Environmental benefits depend primarily upon electricity sources and operational parameters such as aircraft fleet composition.