This paper presents a method for optimal sizing of an off-grid hybrid microgrid (MG) system in order to achieve a certain load demand. The hybrid MG is made of a solar photovoltaic (PV) system, wind turbine (TW) and e...This paper presents a method for optimal sizing of an off-grid hybrid microgrid (MG) system in order to achieve a certain load demand. The hybrid MG is made of a solar photovoltaic (PV) system, wind turbine (TW) and energy storage system (ESS). The reliability of the MG system is modeled based on the loss of power supply probability (SPSP). For optimization, an enhanced Genetic Algorithm (GA) is used to minimize the total cost of the system over a 20-year period, while satisfying some reliability and operation constraints. A case study addressing optimal sizing of an off-grid hybrid microgrid in Nigeria is discussed. The result is compared with results obtained from the Brute Force and standard GA methods.展开更多
Every year in China,a significant number of mines are closed or abandoned.The pumped hydroelectric storage(PHS)and geothermal utilization are vital means to efficiently repurpose resources in abandoned mine.In this wo...Every year in China,a significant number of mines are closed or abandoned.The pumped hydroelectric storage(PHS)and geothermal utilization are vital means to efficiently repurpose resources in abandoned mine.In this work,the development potentials of the PHS and geothermal utilization systems were evaluated.Considering the geological conditions and meteorological data available of Jiahe abandoned mine,a simple evaluation model for PHS and geothermal utilization was established.The average efficiency of the PHS system exceeds 70%and the regulatable energy of a unit volume is over 1.53 kW·h/m^(3).The PHS system achieves optimal performance when the wind/solar power ratio reaches 0.6 and 0.3 in daily and year scale,respectively.In the geothermal utilization system,the outlet temperature and heat production are significantly affected by the injection flow rate.The heat production performance is more stable at lower rate flow,and the proportion of heat production is higher in the initial stage at greater flow rate.As the operating time increases,the proportion of heat production gradually decreases.The cyclic heat storage status has obvious advantages in heat generation and cooling.Furthermore,the energy-saving and emission reduction benefits of PHS and geothermal utilization systems were calculated.展开更多
Although wind and solar power is the major reliable renewable energy sources used in power grids,the fluctuation and unpredictability of these renewable energy sources require the use of ancillary services,thereby inc...Although wind and solar power is the major reliable renewable energy sources used in power grids,the fluctuation and unpredictability of these renewable energy sources require the use of ancillary services,thereby increasing the integration cost.This study proposes a wind,solar,and pumped-storage cooperative(WSPC)model that can be applied to large-scale systems connected to dispersed renewable energy sources.This model provides an optimized coordinated bidding strategy in the day-ahead market,along with a method to facilitate revenue distribution among participating members.This model takes advantage of the natural complementary characteristics of wind and solar power while using pumped storage to adjust the total output power.In the coordinated bidding strategy,a proportion of the energies is provided as firm power,which can lower the ancillary service requirement.Moreover,a multi-period firm power-providing mode is adopted to reflect the wind-solar output characteristics of each period accurately.The duration of each period is selected as a variable to accommodate seasonal characteristics.This ensures that the provision of firm power can maintain a high proportion under varied connected ratios of wind-solar,thereby obtaining higher revenue.By using the revenue distribution method,the short-term influencing factors of the cooperative model are considered to provide the economic characteristics of wind farms and photovoltaic stations.In this way,revenue distribution can be fairly realized among the participating members.Finally,the effectiveness and economy of the proposed model are validated based on actual data obtained from the power grid in California,USA.展开更多
NEOM is a“New Future”city powered by renewable energy only,where solar photovoltaic,wind,solar ther-mal,and battery energy storage will supply all the energy needed to match the demand integrated by artificial intel...NEOM is a“New Future”city powered by renewable energy only,where solar photovoltaic,wind,solar ther-mal,and battery energy storage will supply all the energy needed to match the demand integrated by artificial intelligence techniques.Within this context,the weight of solar thermal is supposed to increase.Concentrated solar power is the only renewable energy with the added value of dispatchability.Opposite to solar photovoltaic and wind,which suffer from intermittency and unpredictability,thus necessitating economically and environ-mentally expensive external energy storage by batteries,concentrated solar power may be fitted with internal energy storage by molten salt providing a much cheaper and environmentally friendly alternative.Oversizing the solar field and the thermal energy storage,the otherwise traditional design with steam Rankine cycles of temperature and pressure to turbine about 565℃ and 100 bar permits highly dispatchable electricity with Lev-elized Cost of Electricity(LCOE)slightly above 7.5¢/kWh in NEOM City,Kingdom of Saudi Arabia.By using higher temperature and pressure to the turbine of 730℃ and 330 bar,the LCOE can be further reduced to below 6.5¢/kWh.While wind and solar photovoltaic are much cheaper,at less than 3–4¢/kWh,their intermittency and unpredictability necessitate energy storage by Lithium-Ion batteries of additional cost 14–28¢/kWh.Likely,the integration of renewable energy technologies through Artificial Intelligence(AI)will be the New Future in NEOM City,with solar photovoltaic,wind,battery energy storage,and solar thermal,the building blocks,and solar thermal increasing the share of energy supply.展开更多
文摘This paper presents a method for optimal sizing of an off-grid hybrid microgrid (MG) system in order to achieve a certain load demand. The hybrid MG is made of a solar photovoltaic (PV) system, wind turbine (TW) and energy storage system (ESS). The reliability of the MG system is modeled based on the loss of power supply probability (SPSP). For optimization, an enhanced Genetic Algorithm (GA) is used to minimize the total cost of the system over a 20-year period, while satisfying some reliability and operation constraints. A case study addressing optimal sizing of an off-grid hybrid microgrid in Nigeria is discussed. The result is compared with results obtained from the Brute Force and standard GA methods.
基金Project(8212033)supported by the Natural Science Foundation of Beijing,ChinaProject(BBJ2023051)supported by the Fundamental Research Funds of China University of Mining and Technology-BeijingProject(SKLGDUEK202221)supported by the Innovation Fund Research Project,China。
文摘Every year in China,a significant number of mines are closed or abandoned.The pumped hydroelectric storage(PHS)and geothermal utilization are vital means to efficiently repurpose resources in abandoned mine.In this work,the development potentials of the PHS and geothermal utilization systems were evaluated.Considering the geological conditions and meteorological data available of Jiahe abandoned mine,a simple evaluation model for PHS and geothermal utilization was established.The average efficiency of the PHS system exceeds 70%and the regulatable energy of a unit volume is over 1.53 kW·h/m^(3).The PHS system achieves optimal performance when the wind/solar power ratio reaches 0.6 and 0.3 in daily and year scale,respectively.In the geothermal utilization system,the outlet temperature and heat production are significantly affected by the injection flow rate.The heat production performance is more stable at lower rate flow,and the proportion of heat production is higher in the initial stage at greater flow rate.As the operating time increases,the proportion of heat production gradually decreases.The cyclic heat storage status has obvious advantages in heat generation and cooling.Furthermore,the energy-saving and emission reduction benefits of PHS and geothermal utilization systems were calculated.
基金This work was supported by the National Natural Science Foundation of China(No.51337005).
文摘Although wind and solar power is the major reliable renewable energy sources used in power grids,the fluctuation and unpredictability of these renewable energy sources require the use of ancillary services,thereby increasing the integration cost.This study proposes a wind,solar,and pumped-storage cooperative(WSPC)model that can be applied to large-scale systems connected to dispersed renewable energy sources.This model provides an optimized coordinated bidding strategy in the day-ahead market,along with a method to facilitate revenue distribution among participating members.This model takes advantage of the natural complementary characteristics of wind and solar power while using pumped storage to adjust the total output power.In the coordinated bidding strategy,a proportion of the energies is provided as firm power,which can lower the ancillary service requirement.Moreover,a multi-period firm power-providing mode is adopted to reflect the wind-solar output characteristics of each period accurately.The duration of each period is selected as a variable to accommodate seasonal characteristics.This ensures that the provision of firm power can maintain a high proportion under varied connected ratios of wind-solar,thereby obtaining higher revenue.By using the revenue distribution method,the short-term influencing factors of the cooperative model are considered to provide the economic characteristics of wind farms and photovoltaic stations.In this way,revenue distribution can be fairly realized among the participating members.Finally,the effectiveness and economy of the proposed model are validated based on actual data obtained from the power grid in California,USA.
文摘NEOM is a“New Future”city powered by renewable energy only,where solar photovoltaic,wind,solar ther-mal,and battery energy storage will supply all the energy needed to match the demand integrated by artificial intelligence techniques.Within this context,the weight of solar thermal is supposed to increase.Concentrated solar power is the only renewable energy with the added value of dispatchability.Opposite to solar photovoltaic and wind,which suffer from intermittency and unpredictability,thus necessitating economically and environ-mentally expensive external energy storage by batteries,concentrated solar power may be fitted with internal energy storage by molten salt providing a much cheaper and environmentally friendly alternative.Oversizing the solar field and the thermal energy storage,the otherwise traditional design with steam Rankine cycles of temperature and pressure to turbine about 565℃ and 100 bar permits highly dispatchable electricity with Lev-elized Cost of Electricity(LCOE)slightly above 7.5¢/kWh in NEOM City,Kingdom of Saudi Arabia.By using higher temperature and pressure to the turbine of 730℃ and 330 bar,the LCOE can be further reduced to below 6.5¢/kWh.While wind and solar photovoltaic are much cheaper,at less than 3–4¢/kWh,their intermittency and unpredictability necessitate energy storage by Lithium-Ion batteries of additional cost 14–28¢/kWh.Likely,the integration of renewable energy technologies through Artificial Intelligence(AI)will be the New Future in NEOM City,with solar photovoltaic,wind,battery energy storage,and solar thermal,the building blocks,and solar thermal increasing the share of energy supply.
文摘利用储能主动参与风光储场站内部调频控制方法,及风电机组和光伏机组配合储能参与风光储场站内部联合控制,以解决风电机组和光伏机组单独控制时带来的电压和频率稳定问题。对风光储各单元采用虚拟同步机(virtual synchronous generator,VSG)控制技术,基于储能的荷电状态(state of charge,SOC)实时调整储能的p-f下垂系数,同时根据风/光机组的功率裕度配合储能调整各自的p-f下垂系数,通过风/光/储联合控制实现系统频率调整。此外,为实现风光储场站系统的二次调频,对VSG技术中的频率-有功控制部分进行了修正,通过实时检测系统频率,对有功功率参考值进行自适应调整;最后,通过阶跃负荷扰动下对比储能单一调频、光储联合调频、风储联合调频及风光储联合调频4种场景来验证所提控制方法的有效性。
