The eco grid was the eco network which stabilized many of Haven City's functional components such as the Shield Wall and the barriers around the city. It was built by Mar and was maintained by Vin and controlled at the power station. Prior to his death, Vin "dumped" his brain in the eco grid so that he could continue to maintain it and manage it (as well as other critical functions for the city) even after he died. The eco for the grid was collected at the eco mine at the time of the city's creation, however, it was abandoned after the eco disappeared. It then drilled for eco in other locations such as the strip mine and the drill platform. In Act 3 of Jak II, Kor sabotaged the grid to deactivate the shields of the city when Sig unintentionally allowed the metal heads into the city through the ruby key in the Underport.
Part of the eco grid was destroyed in the mission "Destroy eco grid with Jinx", after the grid's critical power junctions were detonated by an explosives expert named Jinx, as there were barriers which were blocking Freedom League access to the rest of the Industrial Section and ultimately the Freedom HQ stationed in New Haven during the War for Haven City–without the eco grid, these barriers could not be maintained. However, some of the eco grid survived, namely sections accessed by the power station that contained a cipher glyph to the KG war factory, as Vin was still able to maintain it and communicate with Jak and Daxter in the mission "Find cypher in eco grid".