Advancing Industrial Sustainability and Economics Through a Net-Zero Grid

This article presents a design framework for a net-zero grid aimed at promoting industrial sustainability, specifically addressing challenges posed by industrial loads characterized by low power factor (PF) and high current total harmonic distortion (THD). The net-zero grid integrates photovoltaic (PV) and battery energy storage (BES) as a distributed energy resource (DER), interfaced with industrial loads and the main grid. To enhance the economic viability of the net-zero grid, modular active power filter (APF) design is carried out to mitigate only the load's harmonic current, resulting in a reduced APF size. In turn, the DER regulates the net-zero grid's PF by leveraging the load current to adjust its power injection or absorption to maximize DER economics during peak and off-peak grid demand periods. Furthermore, active and reactive current droop controllers are integrated into the DER controller to provide frequency and voltage support during grid contingencies. Detailed implementations of PV, BES, APF, DER and droop controllers are provided, accompanied by a comprehensive description of the DER reference current generation algorithm. This algorithm helps achieve the objectives mentioned above by enabling seamless coordination among the various subsystems in the net-zero grid. Various test cases are presented to showcase both the high power quality and adherence to grid code requirements in the net-zero grid, as well as the grid support functionalities provided by the DER during frequency and voltage events in the main grid.