Why do some campaigns stop fossil fuel projects, while others fail? Using two conflicts of a power plant in Civitavecchia, Italy, we traced who worked with whom across protests, meetings, and legal and political actions in 2000–2010 and 2018–2023. Protest are not enough to stop these infrastructures; success came when activists built ties with unions, officials, and parties that could block permits and decisions, showing how broad alliances can speed energy choices: a deactivation network.