The studies and development of coal seam gas（CSG） have been conducted for more than 30 years in China, but few of China＇s CSG projects have achieved large-scale commercial success; faced with the boom of shale gas,...The studies and development of coal seam gas（CSG） have been conducted for more than 30 years in China, but few of China＇s CSG projects have achieved large-scale commercial success; faced with the boom of shale gas, some investors are beginning to lose patience and confidence in CSG. China currently faces the following question： Should the government continue to vigorously support the development of the CSG industry？ To provide a reference for policy makers and investors, this paper calculates the EROI_（stnd）[a standardized energy return on investment（EROI） method], EROI_（ide）（the maximum theoretical EROI）, EROI_（3,i）（EROI considering the energy investment in transport）, and EROI_（3,1＋e）（EROI with environmental inputs） of a single vertical CSG well in the Fanzhuang CSG project in the Qinshui Basin. The energy payback time（EPT） and the greenhouse gas（GHG） emissions of the CSG systems are also calculated. The results show that over a 15-year lifetime, EROI_（stnd）, EROI_（ide）, EROI_（3,1）, and EROI_（3,1＋e）are expected to deliver EROIs of approximately11：1, 20：1, 7：1, and 6：1, respectively. The EPT within different boundaries is no more than 2 years, and the life-cycle GHG emissions are approximately 18.8 million kg CO_2 equivalent. The relatively high EROI and short EPT indicate that the government should take more positive measures to promote the development of the CSG industry.展开更多
The index of payback period of dynamic investment is an improvement on index of payback period of static investment, which is the problem that the rules to evaluate the project are feasible or not. This paper proves t...The index of payback period of dynamic investment is an improvement on index of payback period of static investment, which is the problem that the rules to evaluate the project are feasible or not. This paper proves that rules shall be apt when using payback period of dynamic investment to evaluate the project feasibility under the condition of keeping the dynamic evaluation index to evaluate the same scheme and the consistent feasibility.展开更多
Energy access remains a critical challenge in rural South Sudan,with communities heavily relying on expensive and unfriendly environmental energy sources such as diesel generators and biomass.This study addresses the ...Energy access remains a critical challenge in rural South Sudan,with communities heavily relying on expensive and unfriendly environmental energy sources such as diesel generators and biomass.This study addresses the predicament by evaluating the feasibility of renewable energy-based decentralized electrification in the selected village ofDoleibHill,UpperNile,South Sudan.Using a demand assessment and theMulti-Tier Framework(MTF)approach,it categorizes households,public facilities,private sector,Non-GovernmentalOrganizations(NGOs)and business energy needs and designs an optimized hybrid energy system incorporating solar Photovoltaic(PV),wind turbines,batteries,and a generator.The proposed system,simulated in Hybrid Optimization Model Electric Renewable(HOMER)Pro,demonstrates strong economic viability,with a present worth of$292,145,an annual worth of$22,854,a return on investment(ROI)of 36.5%,and an internal rate of return(IRR)of 42.1%.The simple payback period is 2.31 years,and the discounted payback period is 2.62 years.The system achieves a levelized cost of energy(LCOE)of$0.276/kWh and significantly reduces dependence on diesel,producing 798,800 kWh annually fromwind energy.This research provides a replicable model for cost-effective,sustainable rural electrification,offering valuable insights for policymakers and energy planners seeking to expand electricity access in off-grid communities.展开更多
This research investigates the design and optimization of a photovoltaic(PV)water pumping system to address seasonal water demands across five locations with varying elevation heads.The systemdraws water froma deep we...This research investigates the design and optimization of a photovoltaic(PV)water pumping system to address seasonal water demands across five locations with varying elevation heads.The systemdraws water froma deep well with a static water level of 30mand a dynamic level of 50m,serving agricultural and livestock needs.The objective of this study is to accurately size a PV system that balances energy generation and demand while minimizing grid dependency.Meanwhile,the study presents a comprehensivemethodology to calculate flowrates,pumping power,daily energy consumption,and system capacity.Therefore,the PV system rating,energy output,and economic performance were evaluated using metrics such as discounted payback period(DPP),net present value(NPV),and sensitivity analysis.The results show that a 2.74 kWp PV system is optimal,producing 4767 kWh/year to meet the system’s annual energy demand of 4686 kWh.In summer,energy demand peaks at 1532.7 kWh,while in winter,it drops to 692.1 kWh.Meanwhile,flow rates range from 11.71 m^(3)/h at 57 m head to 10.49 m^(3)/h at 70 m head,demonstrating the system’s adaptability to diverse hydraulic conditions.Economic analysis reveals that at a 5%interest rate and an electricity price of$0.15/kWh,the NPV is$6981.82 with a DPP of 3.76 years.However,a 30%increase in electricity prices improves the NPV to$10,005.18 and shortens the DPP to 2.76 years,whereas a 20%interest rate reduces the NPV to$1038.79 and extends the DPP to 6.08 years.Nevertheless,the annual PV energy generation exceeds total energy demand by 81 kWh,reducing grid dependency and lowering electricity costs.Additionally,the PV system avoids approximately 3956.6 kg of CO_(2) emissions annually,underscoring its environmental benefits over traditional pumping systems.As a result,this study highlights the economic and environmental viability of PV-powered water pumping systems,offering actionable insights for sustainable energy solutions in agriculture.展开更多
There is a need for more focus in understanding the economic benefits of Climate-Smart Agriculture(CSA)interventions,particularly in sub-Saharan Africa,where extreme climate events are significantly affecting agricult...There is a need for more focus in understanding the economic benefits of Climate-Smart Agriculture(CSA)interventions,particularly in sub-Saharan Africa,where extreme climate events are significantly affecting agriculture and rural livelihoods.This study used the Net Present Value(NPV),Internal Rate of Return(IRR),Benefit-Cost Ratio(BCR),and payback period to evaluate the economic viability of the adopted CSA interventions in the three villages(Doggoh,Jeffiri,and Wulling)of the dryland farming systems of northern Ghana,where CSA interventions were mostly practiced.Data were collected from 161 farm households by the questionnaire survey.The results showed that CSA interventions including livestock-crop integration,mixed cropping,crop rotation,nutrient integration,and tie ridging enhanced crop yield and the household income of smallholder farmers.The five CSA interventions selected by smallholders were in the following order of priority:livestock-crop integration(BCR=2.87),mixed cropping(BCR=2.54),crop rotation(BCR=2.24),nutrient integration(BCR=1.98),and tie ridging(BCR=1.42).Results further showed that livestock-crop integration was the most profitable CSA intervention even under a pessimistic assumption with a long payback period of 5.00 a.Moreover,this study indicated that the implementation of CSA interventions,on average,was relatively profitable and had a nominal financial risk for smallholder farmers.Understanding the economic viability of CSA interventions will help in decision-making process toward selecting the right CSA interventions for resilience development.展开更多
Ecological payback time was calculated for demolishing an existing commercial building with average energy performance and replacing it with an energy-efficient,prefabricated building.A life-cycle assessment was perfo...Ecological payback time was calculated for demolishing an existing commercial building with average energy performance and replacing it with an energy-efficient,prefabricated building.A life-cycle assessment was performed for a 5,000 ft2 commercial building designed by Project Frog and prefabricated in San Francisco,California,and compared to the impacts of annual energy consumption and continued status quo operation of a comparable average commercial building.Scenarios were run both with and without rooftop solar panels intended to make the prefabricated building net zero energy.The analysis considers the materials and manufacturing,transportation,annual energy use of the new building,and disposal of the existing building,compared to continued annual energy use of the existing building.The carbon payback of a new building with no solar against operation of an existing commercial building was found to be roughly eleven years,and a building with enough rooftop solar to be net zero energy was roughly 6.5 years.The full EcoIndicator99 environmental impact payback for a new efficient building with no solar was found to be twenty years,and a solar net-zero building was roughly eleven years against operation of an existing commercial building.展开更多
基金supported by the National Natural Science Foundation of China (No. 71273277, 71722003, 71690244)the Philosophy and Social Sciences Major Research Project of the Ministry of Education (No. 11JZD048)the National Key R&D Program (2016YFC0208901)
文摘The studies and development of coal seam gas（CSG） have been conducted for more than 30 years in China, but few of China＇s CSG projects have achieved large-scale commercial success; faced with the boom of shale gas, some investors are beginning to lose patience and confidence in CSG. China currently faces the following question： Should the government continue to vigorously support the development of the CSG industry？ To provide a reference for policy makers and investors, this paper calculates the EROI_（stnd）[a standardized energy return on investment（EROI） method], EROI_（ide）（the maximum theoretical EROI）, EROI_（3,i）（EROI considering the energy investment in transport）, and EROI_（3,1＋e）（EROI with environmental inputs） of a single vertical CSG well in the Fanzhuang CSG project in the Qinshui Basin. The energy payback time（EPT） and the greenhouse gas（GHG） emissions of the CSG systems are also calculated. The results show that over a 15-year lifetime, EROI_（stnd）, EROI_（ide）, EROI_（3,1）, and EROI_（3,1＋e）are expected to deliver EROIs of approximately11：1, 20：1, 7：1, and 6：1, respectively. The EPT within different boundaries is no more than 2 years, and the life-cycle GHG emissions are approximately 18.8 million kg CO_2 equivalent. The relatively high EROI and short EPT indicate that the government should take more positive measures to promote the development of the CSG industry.
基金This paper is supported by the National Natural Science Foundation of China （No.59579029）
文摘The index of payback period of dynamic investment is an improvement on index of payback period of static investment, which is the problem that the rules to evaluate the project are feasible or not. This paper proves that rules shall be apt when using payback period of dynamic investment to evaluate the project feasibility under the condition of keeping the dynamic evaluation index to evaluate the same scheme and the consistent feasibility.
文摘July 1st,an important day to mark summer arrival not according to Chinese lunar calendar,but to the habitual way of thinking that hot season sets in.
文摘Energy access remains a critical challenge in rural South Sudan,with communities heavily relying on expensive and unfriendly environmental energy sources such as diesel generators and biomass.This study addresses the predicament by evaluating the feasibility of renewable energy-based decentralized electrification in the selected village ofDoleibHill,UpperNile,South Sudan.Using a demand assessment and theMulti-Tier Framework(MTF)approach,it categorizes households,public facilities,private sector,Non-GovernmentalOrganizations(NGOs)and business energy needs and designs an optimized hybrid energy system incorporating solar Photovoltaic(PV),wind turbines,batteries,and a generator.The proposed system,simulated in Hybrid Optimization Model Electric Renewable(HOMER)Pro,demonstrates strong economic viability,with a present worth of$292,145,an annual worth of$22,854,a return on investment(ROI)of 36.5%,and an internal rate of return(IRR)of 42.1%.The simple payback period is 2.31 years,and the discounted payback period is 2.62 years.The system achieves a levelized cost of energy(LCOE)of$0.276/kWh and significantly reduces dependence on diesel,producing 798,800 kWh annually fromwind energy.This research provides a replicable model for cost-effective,sustainable rural electrification,offering valuable insights for policymakers and energy planners seeking to expand electricity access in off-grid communities.
文摘This research investigates the design and optimization of a photovoltaic(PV)water pumping system to address seasonal water demands across five locations with varying elevation heads.The systemdraws water froma deep well with a static water level of 30mand a dynamic level of 50m,serving agricultural and livestock needs.The objective of this study is to accurately size a PV system that balances energy generation and demand while minimizing grid dependency.Meanwhile,the study presents a comprehensivemethodology to calculate flowrates,pumping power,daily energy consumption,and system capacity.Therefore,the PV system rating,energy output,and economic performance were evaluated using metrics such as discounted payback period(DPP),net present value(NPV),and sensitivity analysis.The results show that a 2.74 kWp PV system is optimal,producing 4767 kWh/year to meet the system’s annual energy demand of 4686 kWh.In summer,energy demand peaks at 1532.7 kWh,while in winter,it drops to 692.1 kWh.Meanwhile,flow rates range from 11.71 m^(3)/h at 57 m head to 10.49 m^(3)/h at 70 m head,demonstrating the system’s adaptability to diverse hydraulic conditions.Economic analysis reveals that at a 5%interest rate and an electricity price of$0.15/kWh,the NPV is$6981.82 with a DPP of 3.76 years.However,a 30%increase in electricity prices improves the NPV to$10,005.18 and shortens the DPP to 2.76 years,whereas a 20%interest rate reduces the NPV to$1038.79 and extends the DPP to 6.08 years.Nevertheless,the annual PV energy generation exceeds total energy demand by 81 kWh,reducing grid dependency and lowering electricity costs.Additionally,the PV system avoids approximately 3956.6 kg of CO_(2) emissions annually,underscoring its environmental benefits over traditional pumping systems.As a result,this study highlights the economic and environmental viability of PV-powered water pumping systems,offering actionable insights for sustainable energy solutions in agriculture.
文摘There is a need for more focus in understanding the economic benefits of Climate-Smart Agriculture(CSA)interventions,particularly in sub-Saharan Africa,where extreme climate events are significantly affecting agriculture and rural livelihoods.This study used the Net Present Value(NPV),Internal Rate of Return(IRR),Benefit-Cost Ratio(BCR),and payback period to evaluate the economic viability of the adopted CSA interventions in the three villages(Doggoh,Jeffiri,and Wulling)of the dryland farming systems of northern Ghana,where CSA interventions were mostly practiced.Data were collected from 161 farm households by the questionnaire survey.The results showed that CSA interventions including livestock-crop integration,mixed cropping,crop rotation,nutrient integration,and tie ridging enhanced crop yield and the household income of smallholder farmers.The five CSA interventions selected by smallholders were in the following order of priority:livestock-crop integration(BCR=2.87),mixed cropping(BCR=2.54),crop rotation(BCR=2.24),nutrient integration(BCR=1.98),and tie ridging(BCR=1.42).Results further showed that livestock-crop integration was the most profitable CSA intervention even under a pessimistic assumption with a long payback period of 5.00 a.Moreover,this study indicated that the implementation of CSA interventions,on average,was relatively profitable and had a nominal financial risk for smallholder farmers.Understanding the economic viability of CSA interventions will help in decision-making process toward selecting the right CSA interventions for resilience development.
文摘Ecological payback time was calculated for demolishing an existing commercial building with average energy performance and replacing it with an energy-efficient,prefabricated building.A life-cycle assessment was performed for a 5,000 ft2 commercial building designed by Project Frog and prefabricated in San Francisco,California,and compared to the impacts of annual energy consumption and continued status quo operation of a comparable average commercial building.Scenarios were run both with and without rooftop solar panels intended to make the prefabricated building net zero energy.The analysis considers the materials and manufacturing,transportation,annual energy use of the new building,and disposal of the existing building,compared to continued annual energy use of the existing building.The carbon payback of a new building with no solar against operation of an existing commercial building was found to be roughly eleven years,and a building with enough rooftop solar to be net zero energy was roughly 6.5 years.The full EcoIndicator99 environmental impact payback for a new efficient building with no solar was found to be twenty years,and a solar net-zero building was roughly eleven years against operation of an existing commercial building.
