In many parts of the world, electric power systems have seen a significant shift towards generation from renewable energy and natural gas. Because of their ability to flexibly adjust power generation in real time, gas-fired power plants are frequently seen as the perfect partner for variable renewable generation. However, this reliance on gas generation increases interdependence and propagates uncertainty between power grids and gas pipelines, and brings coordination and uncertainty management challenges. These interactions are challenging to analyze due to the different dynamics of electricity and gas system dynamics: While the electricity network reaches steady-state operation in seconds, the gas system typically operates in a transient dynamic state. Modelling the gas system dynamics is computationally challenging, but ignoring them can impact the network's ability to supply gas to customers, including gas-fired generation.
In this talk, we will discuss two different problem formulations and solution methods that allow us to assess security of the integrated gas-electric system under consideration of uncertainty and natural gas dynamics. The first framework is a robust problem formulation based on monotonicity properties of the natural gas flow, and provides a clear interface between the two systems at the expense of conservativeness. The second formulation is based on a stochastic hybrid approximation, which we use to demonstrate the importance of considering the gas system dynamics in uncertainty assessment.