Energy, in the broad sense of all sources and forms of energy, fossil, renewable, electricity and fuels, is a latecomer to the field of international organization. The twin principles of permanent sovereignty of producer states over their natural energy resources and the sovereignty of consumer states over their energy mix seemed to remove this matter from the realm of international law and to allocate it to domestic law. The organizational architecture reflects this. Different from other functional systems such as health or trade, there is no single, central international organization of universal membership for the energy sector.