A Novel Relief Strategy in Distribution Grids based on Co-Operation of Electrolysis and Grid-Coupling

Abstract

The energy transition is bringing about a significant change in the energy system. In order to achieve the climate targets across all sectors, photovoltaic (PV) systems, charging stations for electric vehicles, and heat pumps are being installed, particularly in the low-voltage (LV) distribution grid. High PV penetration in the LV level causes reverse power flows when solar radiation is strong and local load is low. This paper presents a novel relief strategy that combines the advantages of an electrolyzer and a converter-based power flow controller (PFC). The central research question focuses on the methodology for dimensioning, controlling, and validating by simulation the cooperative approach, which aims to eliminate the reverse power flow. The dimensioning concept is based on the design of a combined heat and power plant with a peak load boiler. The electrolyzer is deliberately undersized in order to achieve a high number of full-load hours, while the PFC is used to transfer any load peaks that occur. A prerequisite for the effective use of PFCs are complementary consumer areas, so that surplus power that cannot be absorbed by the electrolyzer is used in neighboring grids. The results demonstrate that the integrated approach successfully eliminates 100% of the reverse power flows to the medium-voltage level for the demonstrated day, proving that the proposed combination is a highly effective way to relieve LV grids with high PV penetration.