MODELLING OF ENERGY STORAGE FOR POWER SYSTEM PLANNING AND OPERATIONS

Abstract

Increasing levels of variable renewable energy (VRE) in power systems has made reliable operations of power systems more challenging. Making power systems more flexible is key to addressing this challenge. Production cost simulations help in quantifying the need for grid flexibility and in evaluating the effectiveness of various grid flexibility technologies while minimizing operations costs. Energy storage technologies are expected to play a critical role in making the grid more flexible. But flexibility offered by existing generation resources such as hydro power plants and coal power plants and demand side resources must also be considered when evaluating the amount of energy storage required. Therefore, in this thesis the interplay between the need for energy storage and the presence of flexible generation resources in the grid is explored using an open-source software called Flexible Energy Scheduling Tool for Integrating Variable Generation (FESTIV). Further, the locational value of energy storage is also highlighted by including network constraints in the production cost simulations. The simulations performed on a modified IEEE-118 bus system model with generation characteristics configured to reflect the generation mix in India. The results reveal that while energy storage reduces VRE curtailment, the amount of reduction depends on the flexibility of other generating sources within the system and the consideration of network constraints. For 50% increase in grid flexibility, curtailment reduces from 19.47% to 9.68% when network constraints are not taken into account. Further, it was also observed that instead of developing rules of thumb that require every VRE plant to also develop or contract a certain percentage of energy storage, production cost simulations should be used to identify the additional storage required when adding new VRE plants.