Variable Renewable Generation Expansion Planning And Energy Storage Allocation In Large-scale Power Systems

The development of variable renewables in power systems is regarded as one of the critical efforts for the energy transition and addressing climate change in China.The expan-sion planning approach has a significant impact on the development of variable renewables.Currently,regions with great potentials for variable renewables are given a priority.In cer-tain regions,however,grid integration of variable renewables is heavily limited by opera-tional characteristics of power systems,resulting in severe curtailments.To achieve an in-crease in both installed capacity and electricity generated from variable renewables,an ap-propriate expansion planning approach for variable renewables considering operational characteristics of power systems and potentials for renewables is necessary.On the other hand,changes in energy policies and economic and environmental factors could result in an excessive development of variable renewables.Energy storage is effective to meet the in-creasing need for flexibililty caused by the excessive development of variable renewables.To address the above-mentioned problem,this thesis researches variable renewable generation expansion planning and energy storage allocation for large-scale power systems.Major works included four parts,described as follows:(1)A linear programming(LP)approach to simulating chronological production cost for large-scale power systems is proposed.The computational burden is reduced by group-ing generators and linearizing integer variables that are usually employed to model genera-tors' operational characteristics.The effectiveness of the proposed LP model is verified with an application to the Northeast China Grid case.Compared with the conventional mixed-integer linear programming model,the proposed LP model can ensure the accuracy of simulation results with a great improvement in computational efficiency.The proposed LP model can evaluate long-term chronological production cost for large-scale power sys-tems without employing the rolling solving strategy,providing an effective tool for grid in-tegration analysis and expansion planning of variable renewables.(2)A computationally efficient approach to analyzing grid integration of solar photo-voltaic(PV)in large-scale power systems is proposed.Scenarios are designed to describe different installed capacities of solar PV and system operational requirements.A year-long simulation is then carried out for each scenario to quantify grid integration of solar PV by adopting the above-mentioned LP model.The minimum solar PV capacity can be obtained with a given solar PV energy penetration.Applied to the Northwest China Grid case,the grid integration of solar PV in provincial power systems with different generation mixes is quantified respectively,and operational impacts of coal-fired power plants,hydropower units and wind power on the grid integration of solar PV are analyzed.(3)A novel LP approach for addressing variable renewable generation expansion plan-ning(VRGEP)is proposed,considering both potentials and grid integration of variable re-newables.Potentials and geographic distributions of variable renewables are modeled em-ploying meteorological data with high temporal and spatial resolutions.Operational char-acteristics of power systems are represented by the above-mentioned LP model for chrono-logical production cost simulation.Employing the proposed VRGEP approach,the installed capacities and geographic distributions of variable renewables required to meet a given variable renewable energy penetration target with the objective of minimum investment cost can be derived.The effectiveness of the proposed VRGEP approach is verified with an application to the Northwest China Grid by comparison with the conventional approach that only considers potentials for variable renewables.Impacts of interprovincial power ex-change to the optimal expansion planning of variable renewables are also analyzed.(4)To address the increasing need for system flexibility,a novel approach for energy storage allocation is proposed,supplementing the above-mentioned expansion planning ap-proach.A linear dispatch model is proposed to determine the need for flexibility that can be provided by existing flexible sources and candidate energy storage to accommodate varia-ble renewable generation limited by uncertainty sets.The target of the proposed approach is to minimize the total power capacity of candidate energy storage facilities when the availa-bility of existing flexible sources is limited.The proposed model with uncertainties is dealt with the robust linear optimization method for optimal solutions.The effectiveness of the proposed energy storage allocation approach is verified by case studies carried out in a modified Garver 6-bus system and the Liaoning provincial power system.