Formed of two components – an outdoor sculptural installation and a generative digital installation inside the plant – Passages exothermiques combines the practices of Philippe Allard and Alexandre Burton. They worked from several sources of inspiration: a decomposing leaf through which air and light pass, the heat fluctuations produced by composting, and the polygons generated by the growth of cells. The outdoor installation, standing in the paved walkway leading to the building on Boulevard Henri-Bourassa Ouest, illustrates what happens aboveground. Its triangular monoliths, evoking trees in a forest, come alive in the evening thanks to plays of shadow and light. The indoor component, installed in the hallway leading to the plant’s second-floor educational walkthrough, offers an atmospheric experience representing the exothermic activity – what happens underground – in the plant. The wall’s large reflecting surfaces immerse visitors in an infinite environment, with a multitude of moving light effects triggered in their presence.

The artwork was produced in the context of construction of the Centre de traitement des matières organiques à Saint-Laurent (CTMO), a plant located in the Saint-Laurent borough. Starting in 2025, this CTMO will serve the related municipalities and western boroughs of Montréal; it will compost the digestate from the biomethanization centre in Montréal-Est. In compliance with the Québec government’s Politique d’intégration des arts à l’architecture et à l’environnement des bâtiments et des sites gouvernementaux et publics, the CTMO was required to include an artwork designed specifically for its site.