Integrated Unit Commitment and Natural Gas Network Considering the High Solar Penetration

In this paper, the integrated unit commitment problem and gas network operation in which in the presence of renewable wind and solar power plants is modeled. Both wind and solar energy are variable sources of energy, but because solar energy is only available at certain times of the day, it has caused the load curve behavior to change. This change in load curve, known as the "duck curve, has raised concerns that the power system can provide ramps needed to make full use of solar energy. The use of gas power plants to support the rapid ramp required by the network causes major fluctuations and changes in the gas flow in the gas network. Moreover, change in solar power requires a significant increase in gas power plants’ flexibility. In this paper, we focus on the impact of renewable energy sources on the gas network and vice versa. The use of electricity and gas storage systems, line pack gas network capability as well as the use of PtG technology can be proper solutions to reduce the effects of fluctuations for the safe operation of both electricity and gas networks. In this paper, a convex mixed-integer interval model will be presented for modeling the integrated unit commitment problem and the gas network with high solar penetration condition, gas and electricity storages, line-pack and PtG technology. The proposed model is solved by the Benders decomposition and tested on a modified IEEE 24-Bus test system and Belgian 20-node gas system. According to the results, maximizing the penetration of solar power plants may lead to security alerts in both power and gas systems including sudden pressure drop in the gas system or steep load ramps in the electricity system. While because of the capabilities of the gas system for storing gas and delivering it to gas fired power plants in specific time schedules, joint operation of these two systems can certify secure operation of both gas and electricity systems. Regarding I. R. of Iran vision for expanding solar power plants and considering the role of gas fired power plants as the main source of flexibility in Iran electricity system, it is required to establish a level of cooperation between operators of gas and electricity system to achieve safe operation of both systems while maximizing solar power generation.