Security constrained multi-objective bi-directional integrated electricity and natural gas co-expansion planning considering multiple uncertainties of wind energy and system demand

This study presents a security-constrained optimisation problem for co-expansion planning of integrated electric power and natural gas (SCEP-EPNG), taking into account multiple uncertainties of wind power generation and electric system load demand. The proposed model is a bi-level and bi-directional approach, which considers the flow of electric power to the natural gas network and vice versa through the power to gas and gas to power technologies, respectively. The security of the system is investigated from the static voltage stability point of view using the L-index approach. Also, the information-gap decision theory technique is adopted for modelling the uncertainties. The model aims at minimising the investment and operation costs as well as voltage stability index in a multi-objective optimisation problem, solved by the e-constrained method, and the best compromise solution is calculated using the fuzzy-based min-max method. The proposed SCEP-EPNG model is implemented on the integrated Garver six-node electric power and seven-node natural gas networks, as well as integrated IEEE 24-node electric power and 12-node natural gas networks. Simulation results indicate the importance of voltage stability constraints in long-term energy planning. Furthermore, the model shows the effects of multiple uncertainties on co-expansion planning decisions.