To fully consider the complementary role of different energy sources and reduce the curtailment of renewable energy(RE)in high RE penetration systems,a hierarchical optimization algorithm is proposed to simultaneously...To fully consider the complementary role of different energy sources and reduce the curtailment of renewable energy(RE)in high RE penetration systems,a hierarchical optimization algorithm is proposed to simultaneously optimize the capacity of RE generation and energy storage systems(ESS).Time sequence simulation(TSS)technology is adopted to fully consider the regional RE resource characteristics and make the model more reliable.An optimization model for evaluating ESS capacity is established at a lower level.To overcome the high dimensional complexity of time sequence data,this paper re-formulates this sub-model as a consensus problem,which can be solved by a distributed approach to minimize the system’s total investment costs.At the upper level,the model for assessing the proportion of wind and solar capacity is developed by maximizing the RE generation.The golden section Fibonacci tree optimization(GSFTO)algorithm is utilized to improve the efficiency and solution accuracy.The results show that the algorithm and model are feasible and applicable for the identified purposes,which can provide a useful guidance for the development of power generation and the energy storage capacity in high RE penetration systems.展开更多
High-temperature reactions widely exist in nature.However,they are difficult to characterize either experimentally or computationally.The minimum energy path(MEP)model routinely used in computational modeling of chemi...High-temperature reactions widely exist in nature.However,they are difficult to characterize either experimentally or computationally.The minimum energy path(MEP)model routinely used in computational modeling of chemical reactions is not justified to describe high-temperature reactions since high-energy structures are actively involved at high temperatures.In this study,we used methane(CH4)decomposition on Cu(111)surface as an example to compare systematically results obtained from the MEP model with those obtained from an explicit sampling of all relevant structures via ab initio molecular dynamics(AIMD)simulations at different temperatures.Interestingly,we found that,for reactions protected by strong steric hindrance effects,the MEP was still followed effectively even at a temperature close to the Cu melting point.In contrast,without such protection,the flexibility of the surface Cu atoms could lead to a significant reduction of the free-energy barrier at a high temperature.Accordingly,some earlier conclusions made about graphene growth mechanisms based on MEP calculations should be revisited.The physical insights provided by this study could deepen our understanding of high-temperature surface reactions.展开更多
基金financially supported by the Science and Technology Commission of Shanghai Municipality(20501130200)the National Natural Science Foundation of China(51402342 and 61775201)the National Defense Technology Innovation Special Zone Project.
基金This work was supported jointly by the National Key R&D Program of China(2017YFB0902200)State Grid Corporation of China Science and Technology Project(5228001700CW)the Qinghai Province Science and Technology Plan(2018-GX-A6).
文摘To fully consider the complementary role of different energy sources and reduce the curtailment of renewable energy(RE)in high RE penetration systems,a hierarchical optimization algorithm is proposed to simultaneously optimize the capacity of RE generation and energy storage systems(ESS).Time sequence simulation(TSS)technology is adopted to fully consider the regional RE resource characteristics and make the model more reliable.An optimization model for evaluating ESS capacity is established at a lower level.To overcome the high dimensional complexity of time sequence data,this paper re-formulates this sub-model as a consensus problem,which can be solved by a distributed approach to minimize the system’s total investment costs.At the upper level,the model for assessing the proportion of wind and solar capacity is developed by maximizing the RE generation.The golden section Fibonacci tree optimization(GSFTO)algorithm is utilized to improve the efficiency and solution accuracy.The results show that the algorithm and model are feasible and applicable for the identified purposes,which can provide a useful guidance for the development of power generation and the energy storage capacity in high RE penetration systems.
基金supported by NSFC(21825302)MOST(2016YFA0200604)by USTC-SCC,Tianjin,and Guangzhou Supercomputer Centers.
文摘High-temperature reactions widely exist in nature.However,they are difficult to characterize either experimentally or computationally.The minimum energy path(MEP)model routinely used in computational modeling of chemical reactions is not justified to describe high-temperature reactions since high-energy structures are actively involved at high temperatures.In this study,we used methane(CH4)decomposition on Cu(111)surface as an example to compare systematically results obtained from the MEP model with those obtained from an explicit sampling of all relevant structures via ab initio molecular dynamics(AIMD)simulations at different temperatures.Interestingly,we found that,for reactions protected by strong steric hindrance effects,the MEP was still followed effectively even at a temperature close to the Cu melting point.In contrast,without such protection,the flexibility of the surface Cu atoms could lead to a significant reduction of the free-energy barrier at a high temperature.Accordingly,some earlier conclusions made about graphene growth mechanisms based on MEP calculations should be revisited.The physical insights provided by this study could deepen our understanding of high-temperature surface reactions.
