Two energy-generating technologies in Britain which transform waste into a resource are compared. One is the (in)famous Combined Heat and Power incinerator in Sheffield, the other a forgotten biological digester in Devon utilizing anaerobic microbes. Both sites are early exemplars of experimental and biopolitical waste disposal technologies—incineration and anaerobic digestion—now regarded as leading alternatives for reducing the United Kingdom’s dependence on landfill and fossil fuel; both sites also inspired public resistance at critical moments in their development. The analysis here relates how activists and technicians struggle to demonstrate competing truths about alternative energy. Through comparison, it becomes clear that, beyond the validity of specific truth claims, energo-politics mediates the formation of technological legacies. Examining the traces energy facilities leave behind—whether in the landscape or online—we ask what it means that various claims made about some technical operations endure, while others fade into obscurity.