Smart Data Models’ Candidates repository now includes a new candidate standard translated from the Open Energy Ontology (OEO): open-energy-ontology, with 5 candidate models for power plants, generating units, energy storage and supply grids. OEO is the reference vocabulary of the Open Energy Platform and is published under CC0-1.0. Like every candidate, each model comes with a JSON Schema, an NGSI-LD @context and all four example serializations (NGSI-v2 and NGSI-LD, key-values and normalized), each validated against its schema.
About the Open Energy Ontology
OEO is a domain ontology for energy system modelling and analysis, built on the Basic Formal Ontology (BFO). Release v2.14.0 (October 2026), the one translated here, has more than 1,300 classes of its own. They cover the physical energy system (power plants, units, converting components, storage, grids, fuels and energy carriers), quantities and units, and the research side of the field: models, scenarios, studies and data sets.
The models
| Model | OEO class | OEO subclasses covered | Examples of oeoClass values |
|---|---|---|---|
PowerPlant |
power plant (OEO_00000031) | 37 | lignite power plant, combined cycle gas power plant, offshore wind farm, pumped hydro storage power plant |
PowerGeneratingUnit |
power generating unit (OEO_00000334) | 30 | gas fired power unit, nuclear power unit, wind energy converting unit, PV panel |
EnergyStorageObject |
energy storage object (OEO_00000159) | 29 | lithium-ion battery, flow battery, sensible heat storage object, underground hydrogen storage object |
GridComponent |
grid component (OEO_00020006) | 19 | grid node, switchyard, transformer, HVDC-line, vehicle charging station |
SupplyGrid |
supply grid (OEO_00000200) | 7 | transmission grid, distribution grid, gas grid, heating grid, control area |
The models are linked by OEO’s own relations: a plant hasPart its units, a component is partOf a grid, grid nodes are isConnectedTo each other, a grid has a hasSource and a hasSink, and a unit uses its fuel (natural gas, lignite, … as OEO class IRIs). In NGSI-LD these become Relationships.
Grounded in real data
Four of the five examples describe one real installation, using Open Power System Data records (CC-BY-4.0, from the BNetzA and UBA power plant lists): the Irsching power plant in Bavaria, its unit 4 “Ulrich Hartmann” (561 MW net, efficiency 0.604, natural gas combined cycle), the extra-high-voltage grid node it connects to, and the TenneT transmission grid. Units and plants are identified by their ENTSO-E EIC codes.
Translation notes
- One entity type per branch, not one per class. OEO is mainly a classification taxonomy. Following the approach of the Brick candidate, each model is generic, and an
oeoClassattribute holds the specific OEO subclass. It is restricted to an enum of every class in that branch (122 classes in total), none of them deprecated. - Readable names, real IRIs. OEO identifies its classes by numbers such as
OEO_00000031, so the entity and property names are the PascalCase or camelCase form of OEO’s English labels. Every@contextmaps them back to the exact OEO or BFO IRI. - Quantities flattened. OEO models capacities, efficiencies and dates as separate quantity-value classes (nameplate capacity, declared net capacity, energy storage capacity, efficiency value, full load hours…). Here they are plain numeric attributes in a fixed unit (MW, MWh, ratio, hours, years).
- A few practical extras.
operationalStatus,eicCode,gridOperatorandrefGridConnectionPointare not OEO terms. They were added for operational NGSI-LD use and are marked as such in each schema.
Try it, and tell us what’s missing
These are Candidates: first, carefully sourced translations that are not yet official Smart Data Models subjects. Before that step, the main open question is overlap with existing energy models: dataModel.Energy, dataModel.GreenEnergy, dataModel.EnergyStorage, dataModel.EnergyCIM and the SAREF4ENER and SAREF4GRID candidates. Natural next steps are energy converting components (generators, turbines), combined heat and power and heat plants, and OEO’s scenario and study branch.
Browse the models, open an issue, or send a PR:
👉 https://github.com/smart-data-models/Candidates/tree/master/standards/open-energy-ontology
