After three years of procedures, the urban plan to build a macro biogas plant in Sentiu de Sió (Noguera) has received the green light from the Barcelona Urban Planning Commission. It is the largest facility of its kind in southern Europe—it will process around 500,000 tons annually—and could be the first in a wave of biogas factories in Ponent, as part of the rollout of the Catalan Biogas Strategy 2024-2030. However, both the approval of the urban plan and the possibility of more factories proliferating have sparked outrage among some thirty mayors in the region, who are standing firm against the project and have announced they will challenge it in court. Despite the silence of the Generalitat (Catalan Government), the mayors warn that the factory will not be able to operate solely with local slurry and that, in practice, it is a black hole for the Danish investment fund leading it—Copenhagen Infrastructure Partners—to do business with waste that will come either from Aragon or the province of Barcelona. This waste includes animal remains and slaughterhouse waste, and not just slurry.