The Open Energy Ontology is an ontology for all aspects of the energy modelling domain. The Physical module covers all those aspects of the world that are relevant for the energy systems domain, including physical entities such as generators, power lines, technologies, portions of matter; attributes of those, such as the energy they carry or release, whether they can be a pollutant, or their origins; representational transformations into maps and measures, such as coordinates, units, quantities; and the processes that modify the physical entities, such as energy production.