Function-space optimization to coordinate multi-energy storage across the integrated electricity and natural gas system

Abstract

The synergy between electric power systems and natural gas systems brings significant energy storage potentials yet challenges the modeling and solution techniques of partial-differential-equation (PDE) constrained optimization. This paper proposes a function-space optimization to coordinate multi-energy storage across the integrated electricity and natural gas system. Compared to general algebraic-space optimization, the proposed function-space optimization (FSO) uses continuous spatial–temporal functions as variables, for which time and space can be explicitly expressed and the PDE constraints of gas dynamics can be directly embedded into optimization. Considering the bidirectional energy conversion enabled by gas-fired units and power-to-gas, linepack gas storage and battery energy storage are coordinated through FSO to improve the operational economy. For tractable calculation, the Bernstein polynomial spline-based solution space transformation is adopted to transform FSO into mixed-integer linear programming. Case studies on a single-pipe example and two practical test systems are conducted and the simulation results validate the effectiveness of the proposed FSO method.