Integrated unit commitment and natural gas network operational planning under renewable generation uncertainty

In this paper, we study an important variant of integrated unit commitment problem and gas network in which uncertain renewable energy resources, gas and electricity storage, the capability of line-pack of the gas network (gas stored in the pipeline), and Power to Gas (PtG) are taken into account. The motivation of this paper is to enhance the security of power generation and optimize both electrical and gas network operational cost. Uncertainty of renewable sources in a power system will inevitably increase the power system's dependence on traditional gas power plants. As a result, the uncertainty of renewable sources is transferred to the gas network such that the fluctuations of the gas flow would increase. Gas and electricity storage, the capability of line-pack of gas network and the use of PtG technologies help us to manage the effect of renewable sources on electricity and gas network. Here, we formulate a mixed integer non-linear optimization model to present the integrated unit commitment problem. Given the complexity of the underlying problem, we explore the problem structure and propose a novel reformulation consisting of efficient decomposition and convexification techniques. Compared to existing methods whose quality are sensitive to initial solutions, the proposed model is more flexible and offers significant improvements in solution quality and efficiency. The proposed model is tested on a modified IEEE 24-Bus test system and Belgian 20-node gas system.