Control of Line Pack in Natural Gas System: Balancing Limited Resources under Uncertainty

TL;DR

This paper develops a control strategy for managing the line pack in Israel's natural gas system, addressing uncertainties and dynamic challenges to ensure stable operation and meet fluctuating demand.

Contribution

It introduces a novel control approach tailored for a unique natural gas system with limited control points and no inland compressors, incorporating uncertainty and dynamic demand.

Findings

Robust control methods effectively manage intra-day gas flow variations.

Simulation results demonstrate system stability under uncertain withdrawal patterns.

Monotonicity properties aid in ensuring robustness of control strategies.

Abstract

We build and experiment with a realistic but reduced natural gas model of Israel. The system is unusual because (a) it is controlled from a limited number of points which are at, or close to, the gas extraction sites offshore of Israel's Mediterranean coast; (b) control specifies average flux at inlet, not pressure; (c) there are no inland compressors to regulate pressure; (d) power system is the main consumer of gas (70\% of Israel's power is generated at gas-fired power plants distributed across the country). Nature of the system suggests that a special attention should be given to understanding dynamics driven by fast transients in gas consumption meeting intra-day variations in the electricity demand, and accounting for increasing role of uncertain renewable generation (mainly solar). Based on all of the above we pose and resolve a sequence of dynamic and control challenges, such as: How to time ramping up- and down- injection of gas to guarantee a healthy intra-day line-pack which meets both pressure constraints and gas-extraction patterns? We report simulation results and utilize monotonicity properties of the natural gas flows which render robustness of our conclusions to the uncertainties of the edge withdrawals of gas.