Coordinated operation strategies for natural gas and power systems in presence of gas‐related flexibilities

Abstract

A detailed investigation of the interaction between natural gas and power systems is necessary, due to the increasing interdependency of these vectors, especially in the context of renewable generations integration growth into the grid. In this study, an outer approximation with an equality relaxation decomposition method is proposed to solve a mixed-integer non-linear problem representing the operation of coupled natural gas and power systems. The proposed coupled modelling of natural gas and power systems is compared to decoupled operational modelling. It is demonstrated that operating gas and electricity as a coupled system resulted in about 7% of operational cost savings. In addition, the value of gas-related flexibility options, including flexible gas compressors, flexible gas generation plants, and gas interconnections, to the operation of natural gas and power systems is quantified for a 2030 GB energy system. It is shown that if the natural gas and power systems are flexible enough, the operation of the systems in the decoupled approach is almost the same as the coupled model and therefore there is no need to reform the current energy market framework to make the systems fully coupled.

Coordinated Operation of Gas and Electricity Systems for Flexibility Study

“…The constraints governing the electricity system over the time horizon (t ∈ T ) are represented by equations (1)-(11). These constraints include: minimum and maximum power generation limits for generators (1), Minimum Stable Generation (MSG) for thermal generators (2), maximum limit for power generation and provision of reserve by thermal generators (3), Minimum Up/Down Time (MUT/MDT) of generators (4)-(5), ramp up/down limits of generators (6), start-up cost of generators (7) (8), minimum reserve requirement (including the unserved reserve) (9) (Ameli et al, 2019), capacity of power transmission lines (10), and power balance at each time step (11).…”

“…The operation of the gas system over the time horizon (t ∈ T ) is modeled via constraints for gas flow along a pipe (12) (Osiadacz, 1987) (detailed formulation is presented in Ameli et al, 2019), power consumption by the compressors 14, changes in the gas system linepack (15), minimum and maximum pressure limits (16), and gas balance at each node and time step (17). In order to model a bi-directional gas flow, in the gas flow equation in (12), the term Q…”

Information-Gap Decision Theory for Robust Operation of Integrated Electricity and Natural Gas Transmission Networks

“…Furthermore, gas compressors driven by electricity as well as the emergence of power to gas (Pegs) technology, increases the interdependency of gas and electricity systems [2]. Therefore, as this interaction between the electricity and natural gas infrastructures increases, operation of each network will impact the other energy vector, which emphasizes the importance of coordinated operation of ENGN from operation [3]- [5] and planning perspectives [6].…”

“…In [5], the iterative and integrated operation models are compared, and it is shown that under completely identical conditions, the integrated method results in about 7% cost savings. It is also shown that the cost difference could be reduced by using flexible elements such as multi-directional compressors or flexible GFUs.…”

“…The inequality (4) limits the output power of the generating units to a minimum and maximum allowable output power per hour. Equation (5) presents the relationship between binary variables related to the On/Off (0/1) status of the unit commitment approach, and start-up and shut-down status of generating units. The constraints on the minimum up and down time are given in (6) and 7, respectively.…”