Utilization of Water Supply Networks for Harvesting Renewable Energy

TL;DR

This paper presents a novel framework for using water supply networks to absorb surplus renewable energy, optimizing pump schedules through advanced mathematical relaxations and demonstrating its effectiveness via simulations.

Contribution

It introduces a new method to utilize water networks for energy harvesting, employing a second-order cone relaxation and an algorithm for optimal pump scheduling.

Findings

The proposed relaxation is exact under certain conditions.

The framework effectively absorbs surplus renewable energy.

Numerical simulations validate the approach's efficiency.

Abstract

Renewable surplus power is increasing due to the increasing penetration of these intermittent resources. In practice, electric grid operators either curtail the surplus energy resulting from renewable-based generations or utilize energy storage resources to absorb it. In this paper, we propose a framework for utilizing water pumps and tanks in water supply networks to absorb the surplus electrical energy resulting from renewable-based electricity generation resources in the electrical grid. We model water supply networks analytically, and propose a two-step procedure that utilizes the water tanks in the water supply network to harvest the surplus energy from an electrical grid. In each step, the water network operator needs to solve an optimization problem that is non-convex. To compute optimal pump schedules and water flows, we develop a second-order cone relaxation and an approximation technique that enable us to transform the proposed problems into mixed-integer second-order cone programs. We then provide the conditions under which the proposed relaxation is exact, and present an algorithm for constructing an exact solution to the original problem from a solution to the relaxed problem. We demonstrate the effectiveness of the proposed framework via numerical simulations.