Maximum Production Point Tracking of a High-Temperature Power-to-Gas System: A Dynamic-Model-Based Study

TL;DR

This paper develops a dynamic-model-based MPPT strategy for high-temperature Power-to-Gas systems, coordinating multiple parameters to enhance efficiency and responsiveness under fluctuating renewable power inputs.

Contribution

It introduces a novel MPPT control method for HT-P2G that considers temperature and feed rates, unlike previous steady-state focused approaches.

Findings

MPPT responds rapidly to load changes

Conversion efficiency is improved

Loading capacity increases

Abstract

Power-to-gas (P2G) can be employed to balance renewable generation because of its feasibility to operate at fluctuating loading power. The fluctuating operation of low-temperature P2G loads can be achieved by controlling the electrolysis current alone. However, this method does not apply to high-temperature P2G (HT-P2G) technology with auxiliary parameters such as temperature and feed rates: Such parameters need simultaneous coordination with current due to their great impact on conversion efficiency. To improve the system performance of HT-P2G while tracking the dynamic power input, this paper proposes a maximum production point tracking (MPPT) strategy and coordinates the current, temperature and feed rates together. In addition, a comprehensive dynamic model of an HT-P2G plant is established to test the performance of the proposed MPPT strategy, which is absent in previous studies that focused on steady states. The case study suggests that the MPPT operation responds to the external load command rapidly even though the internal transition and stabilization cost a few minutes. Moreover, the conversion efficiency and available loading capacity are both improved, which is definitely beneficial in the long run.