Passive radiative cooling panels are produced by anodizing an aluminum foil sheet to form metamaterial nanostructures and then forming a plated metal over the metamaterial nanostructures to produce an ultra-black emitter, and then securing a reflective layer (e.g., a solar mirror film) onto the ultra-black emitter. The process is implementable in a roll-to-roll-type fabricating system in which a continuous aluminum foil ribbon extends from a feed roll through an anodization station to a reflector mounting station such that a first ribbon section undergoes anodization while a second ribbon section undergoes plating and a reflective layer is mounted onto a third ribbon section. A modified Anodic Aluminum Oxide (AAO) self-assembly technique is utilized to generate tapered nanopores that are then plated to generate an ultra-black emitter capable of generating broadband radiant energy with an emissivity close to unity. Modules are produced by mounting the panels onto conduit structures.