Energy Storage Planning For Large Scale Renewable Energy Integrated Power Systems

With the increasing penetration of renewable energy generation,power systems around the world are developing towards the direction of green and low carbon.However,the volatility and uncertainty of large scale renewable power bring new challenges on the power supply ensurance in power systems.The gradual maturity of utility-scale energy storage technology provides a new option to address the aforementioned issue.Compared with other existing solutions,energy storage can exert its flexibility advantage in some certain application scenarios.In this work,utility-scale energy storage is regarded as a technical option for power system planning problems.We aims to combine the technical features of various types of devices to achieve a coordinated planning of energy storage and other options in power systems.The major research contents of this paper are as follows:1)In the scope of energy storage requirement analysis,a system operational bottleneck identification based requirement analysis method is proposed.A formulation for system operational bottleneck identification is established,in order to obtain operational restriction indices to quantify adequacy of power adjustment margin and power ramp rate.A cosine similarity based clustering method is used to cluster a large number of scenarios by operational restriction indices,then scenarios with bottlenecks are attributed to corresponding clusters.Finally,various bottleneck elimination options,including energy storages with different technologies,are compared for each cluster.2)In the scope of system operational bottleneck emlimination,an energy storage optimal planning model is proposed to determine the storage type and capacity,while considering the strong volatility of the renewable power.The proposed model can be used to eliminate the system bottlenecks,and make system power balance requirements satisfied.Due to high price of energy storage for the time being,in order to reduce investment cost,the proposed model is able to combine technical features of energy storages and conventional generators.The case study shows that advantages of energy storage on large ramp rate,wide operation range and flexible start-up/shut-down ability are more applicable to cope with wind power ramp events.3)In energy storage and generation expansion co-planning,a novel formulation considering renewable generation uncertainty is presented using an interval optimization based approach,which is proved to be applicable for the specific mixed integer linear operational sub problem.The proposed approach has the advantage of covering all the worst cases,while keeping a concise and easy-to-implement formulation with moderate problem size.Moreover,in order to decrease the conservativeness of the investment decision,a dual interval policy is introduced to achieve a better tradeoff between system security and investment economy.Case studies of a modified IEEE 24-bus test system and a practical Chinese provincial power system were used to test the proposed approach.4)In energy storage and transmission line expansion co-planning,a robust formulation is proposed considering binary variables that represent energy storage statuses in the recourse problem.In order to solve this model,an improved nested column and constraint generation algorithm is used to overcome numerical issues caused by new binary variables,big-M constraints,and the enormous size of the formulation.Case studies of a modified Garver's 6-bus system and a practical Chinese 196-bus system were used to assess the effectiveness of the proposed approach.