This article will examine the significance of the alternative film scene, as seen in the Spanish militant cinema of this period, through an analysis of the film Les energies (‘The energies’) (1979–80) by the Cooperativa de Cinema Alternatiu (CCA – Alternative Cinema Cooperative) that helped to trigger the debate on the energy question in Spain in the late 1970s and early 1980s. The militant Spanish cinema of that time was produced in some exceptionally precarious conditions as well as had limited access to financial resources and remained marginal to official film industry systems. The article will discuss how these production conditions led the CCA to adopt a specific material filmmaking mode with a low ecological impact. Emerging as a consequence of a production context marked by precariousness and (semi-)clandestinity, it was a mode of production developed in parallel to the rise of environmental awareness in Spain, which had – as the first part of this article explores – a decisive influence on the CCA. In turn, as the article goes on to discuss, the environmentalist discourse would itself end up determining the narrative content of one of the CCA’s most important films, Les energies.