A unique id of 128 bits, written as 32 characters in five groups. What makes it useful is not the length but the fact that anyone can create one without asking permission.
Definition
UUID stands for universally unique identifier. Microsoft calls the same thing a GUID. It is usually written as 8-4-4-4-12 hexadecimal characters separated by hyphens, such as f47ac10b-58cc-4372-a567-0e02b2c3d479. The format is standardised by the IETF, originally in RFC 4122 and since superseded by RFC 9562.
What matters is not the size of the number space but the absence of an issuer. No central authority hands out UUIDs. A system that needs an identifier creates one itself, at any time, without a network and without coordinating with anyone. The space is large enough that two independently generated ids will in practice never collide.
That property is what makes them usable across systems that do not know about each other. Two databases that have never spoken can be merged without their ids clashing, and an id created in a field tool with no coverage still holds when the device comes back online.
A UUID says nothing about what it points to. It cannot be read, meaningfully sorted or guessed, and for exactly that reason it is a poor replacement for a name or an installation number. It is a key, not a description.
Compare it with the GS1 numbers the sector otherwise uses. A GLN or a GSRN is allocated: someone owns the number series and you receive your slice of it. That gives traceability to an issuer, and it costs coordination. A UUID gives the opposite: no coordination, no issuer to ask, and no meaning in the number itself.
Both are needed. The metering point has a GSRN because the whole market has to agree on it. The component in the installation has a GlobalID, which is a UUID, because no central authority hands out identities to the breakers in a substation.
RUNA assigns the GlobalID at goods receipt. That is the earliest point at which the component exists as a physical thing on our side, and from then on the id follows it through relocations, changes of ownership and changes of system.
In practice
Compare it with the GS1Global standards organisation known for barcodes, GTIN and GSRN - the standard behind unique metering point IDs in the electricity market. numbers the sector otherwise uses. A GLNA Global Location Number from GS1 - thirteen digits that uniquely identify a legal entity or a place. In the power market the GLN is a participant's identity. or a GSRNGlobal Service Relation Number - the unique 18-digit identifier for each metering point in Elhub, based on the GS1 standard. is allocated: someone owns the number series and you receive your slice of it. That gives traceability to an issuer, and it costs coordination. A UUID gives the opposite: no coordination, no issuer to ask, and no meaning in the number itself.
Both are needed. The metering pointThe fundamental unit in Elhub - the unique point in the electricity network where energy is measured and settled, identified by an 18-digit GSRN number. has a GSRN because the whole market has to agree on it. The componentA replaceable part inside a fixed asset. It has its own age, its own history and its own service life - independent of the asset it sits in. in the installation has a GlobalIDA unique id that follows a component for its entire lifetime, across every system it appears in. The technical term for it is UUID., which is a UUID, because no central authority hands out identities to the breakers in a substation.
RUNATvimenning's component register for electrical installations - providing structure and traceability for the components installations are built from. assigns the GlobalID at goods receipt. That is the earliest point at which the component exists as a physical thing on our side, and from then on the id follows it through relocations, changes of ownership and changes of system.
