Source
https://www.iea.org/data-and-statistics/data-tools/energy-technology-classification-system — original source (opens in a new tab; the file is not redistributed)
Summary
The IEA’s official 9-group energy technology classification, updated in 2025 in cooperation with 32 IEA member governments (including New Zealand). Originally developed in the 1970s to organise IEA member countries’ public RD&D budget reporting; now also the structural backbone of the ETP Clean Energy Technology Guide and “The State of Energy Innovation”. Spans 163 pages of hierarchical definitions — 9 letter-coded high-level groups (A–H, Z) divided into numbered sub-categories with cross-referenced “Excludes Ref. X” pointers — covering energy end uses, fossil fuels, renewables, nuclear, hydrogen, heat & power, CO2 capture, critical minerals, and cross-cutting technologies. Provides the controlled vocabulary for grounding the Neobiome Intelligence calculation skill at the granularity calculation parameterisation actually requires, with explicit catalogue of misalignments where the IEA framing diverges from community-SS framing.
Key claims
- 9 high-level groups + hierarchical NEC mechanism. IEA Energy Technology Classification 2025 organises all energy technologies under 9 letter-coded groups: A Energy end uses; B Fossil fuels; C Renewable energy sources; D Nuclear fission and fusion; E Hydrogen, hydrogen-based fuels and fuel cells; F Heat and power generation, storage, and supply; G CO2 capture and storage; H Critical minerals; Z Cross-cutting technologies and research. Each high-level group is divided into numbered sub-categories (A1, A11, A111…) with explicit “Excludes Ref. X” cross-references and a “not elsewhere classified” (NEC) bucket at every level (A9, A19, A129…). OT_022
- Four classification logics, deliberately mixed. IEA names technological basis, end-user basis, energy supply basis, and cross-sectoral technology activity basis. Acknowledges no single logic is satisfactory; the 9-group system mixes all four to reflect real-world organisation of research, sales and investment activities. Methodological cover for any subsequent taxonomy work (incl. EDT) that mixes logics rather than purifying from one principle. OT_022
- A2 Residential and commercial buildings — A21 Building design and envelope (A211 envelope tech, A212 building design incl. AI-aided, A219 NEC); A22 Buildings operations and efficient building equipment (A221 energy management systems incl. smart meters, A222 lighting, A223 heating/cooling/ventilation, A229 NEC); A23 Appliances and equipment excl. heating/cooling (A231 cooking, A232 energy-efficient ICT, A239 NEC); A24 Urban and spatial energy planning; A29 NEC. A223 leaf-level: A2231 Building heat pumps (air-source / ground-source / water-source / hybrid), A2232 Hydrogen in heating, A2233 Bioenergy in heating (biomass stoves and burners), A2239 NEC. OT_022
- A3 Transport — A31 Road (A311 on-board storage incl. batteries A3111, A312 EV/HEV power electronics, A313 combustion engines and biofuels, A314 EV charging infrastructure incl. A3141 digital smart charging, A315 hydrogen for road transport, A316 materials, A319 NEC); A32 Rail; A33 Aviation; A34 Shipping; A35 Other non-road incl. tractors/forklifts/construction vehicles; A39 NEC. Active mobility (walking, cycling, pedal electric cycles) explicitly “Out of scope” under A31. OT_022
- A4 Agriculture and forestry — single category with NO sub-codes. IEA treats it as “techniques to reduce energy consumption/emissions in forestry and agriculture”, with only 3 illustrative bullets (energy-efficient equipment, fertiliser efficiency, research on practices). Bioenergy production from biomass is explicitly excluded (Ref. C4). Structural signal: IEA does not treat food/agriculture as a peer domain. OT_022
- A5 Construction and civil engineering — single category with NO sub-codes. Covers materials use (incl. wood) and process improvements during construction works; explicitly excludes the design of energy-efficient buildings once built (Ref. A212). A6 Data centres also a single category with no sub-codes. OT_022
- C1 Solar energy — C11 Solar heating and cooling (incl. flat plate collectors, solar drying, solar water heating, solar cooking); C12 Solar photovoltaics (C121 Solar cell technologies — incl. PERC, TOPCon, heterojunction, perovskite, organic, thin-film; C122 Solar modules; C123 Integrated photovoltaics — BIPV/IPV; C124 Solar photovoltaics systems — covers utility-scale, residential, agrivoltaics, floating PV in a single code; C129 NEC); C13 Solar thermal power and high-temperature applications (CSP); C19 NEC (incl. solar forecasting). OT_022
- C2 Wind energy — C21 Onshore wind technologies — explicitly includes “small-scale technologies including rooftop and community scales” alongside MW-scale and off-ground/high-altitude wind, but without separate sub-codes for these scales; C22 Offshore wind (C221 fixed-bottom monopile/jacket/gravity-based/tripod, C222 floating spar-buoy/semi-submersible/tension-leg/barge platforms, C229 NEC); C29 NEC (covers hybrid systems and wind resource/site characterisation). OT_022
- C4 Bioenergy — C41 Liquid biofuels (C411 Biogasoline, C412 Biodiesel — FAME/HVO/microalgal, C413 Biojet kerosene/SAF, C419 NEC); C42 Solid bioenergy (C421 Fuelwood/wood residues/by-products, C422 Charcoal and biochar, C429 NEC); C43 Gaseous bioenergy (C431 Thermal/gasification, C432 Anaerobic fermentation/biogas, C433 Biomethane production via water scrubbing/PSA/membrane separation, C439 NEC); C44 Bioenergy applications for heat and electricity incl. CHP; C45 Biorefining; C49 NEC (covers energy crop and algae research, land-use impacts). OT_022
- C5 Geothermal energy — C51 Hydrothermal resources (dry steam, flash steam, binary cycle); C52 Enhanced geothermal systems (hydraulic/thermal/chemical stimulation); C53 Closed-loop geothermal systems; C54 Drilling and exploration incl. geosciences; C59 NEC — explicitly includes “low-temperature applications (below 150°C) including the extraction of shallow geothermal heat” and “collecting, treating and piping hot water and steam for direct use (for greenhouses, aquaculture or community usage)” — but as a bullet, not a sub-code. OT_022
- C6 Hydroelectricity — IEA defines the cut at 10 MW — C61 Large hydroelectricity (≥10 MW); C62 Small hydroelectricity (<10 MW) incl. run-of-river devices; C69 NEC. Pumped hydro storage is NOT under C6 — classified separately as F512 mechanical storage. C62 lumps community pico/micro/mini-hydro in one bucket — too coarse for community-scale parameterisation. OT_022
- F1 Heat and power generation (technology-agnostic — excludes anything specific to fossils/renewables/nuclear/H2) — F11 Heat and power generation technologies incl. CHP not covered elsewhere, organic Rankine cycles, Stirling engines, thermoacoustics, magneto-hydrodynamics; F12 Supporting technologies (cooling, M&V, sensors); F19 NEC. F2 Electricity transmission and distribution: F21 T&D technologies (F211 Cables and conductors incl. HVDC, F212 AC/DC conversion incl. grid-forming and smart inverters, F219 NEC); F22 Grid communication, control systems and integration (F221 Load management incl. DERMS, grid integration of variable renewables, VPP, metering infrastructure; F222 SCADA, drones for inspection, dynamic line rating; F223 Standards/interoperability/cybersecurity incl. mesh networks; F229 NEC); F3 District heating and cooling (F31 District heat pumps, F39 NEC); F4 Waste energy recovery and utilisation incl. thermoelectricity, low-temp Rankine cycles, waste heat from data centres or wastewater plants. OT_022
- F23 Mini grids and microgrids — the formal IEA code for NI’s design unit. Defined as “localised energy systems that can operate independently or in conjunction with the main grid… typically used for rural electrification, disaster recovery and remote or islanded energy generation”. Sits inside F2 (T&D) — IEA classifies microgrids as a distribution-network concept, not a generation concept. The framing is “rural electrification / resilience”, not “intentional-community self-sufficiency” — NI uses the code but the definitional language doesn’t quite translate. OT_022
- F5 Energy storage (excluding transport) — F51 Electrical storage (F511 Batteries — all rechargeable electrochemical incl. Li-ion, flow batteries, redox flow, supercapacitors, ultracapacitors, ALSO including manufacturing/reuse/recycling/LCA; F512 Mechanical storage — pumped hydro, CAES, liquid air, flywheels; F519 NEC — incl. photochemical, superconducting magnetic energy storage). F52 Thermal energy storage — hot water, phase change materials, molten salts. F59 NEC. F511 is the formal IEA code for community BESS — distinct from A3111 EV batteries. OT_022
- Z Cross-cutting — Z1 Energy system analysis — “sociological, economic and environmental impact of energy”, “behavioural and other social science research into energy”, “modelling related to energy”. Z2 Digital tools for energy systems — incl. AI applications, blockchain peer-to-peer energy markets, pay-as-you-go mobile payments, locational bidding tools, emissions tracing. Z9 NEC. Note: VPPs are at F221 (not Z2). The IEA Energy Technology Classification has 32 IEA Member countries including New Zealand, so MBIE-reported NZ energy statistics are implicitly structured to be reportable under this classification. OT_022
Neobiome Intelligence relevance
- F23 Mini grids and microgrids is the formal IEA code for the community-scale energy systems NI is designed to size — and the IEA places it inside F2 (Transmission and Distribution), not C (Renewables) or F1 (Generation). This is methodologically important: the IEA frames microgrids as a distribution-network concept that integrates whatever generation sits behind it. The NI calculation skill should adopt the same framing — microgrid design is a question of integrating sources, not picking one.
- C124 Solar photovoltaics systems is the leaf code that covers all PV system sizes from residential rooftop through utility-scale ground-mount, including agrivoltaics and floating PV. The NI energy skill can use C124 as its top-level vocabulary entry for “PV system” and drill into C121 (cells), C122 (modules), C123 (BIPV) only when the question is sub-system specific. But note — the single code lumps utility-scale and residential together; NI sizing needs to maintain its own scale split.
- F511 Batteries (excluding transport applications) is the formal code for community BESS, distinct from A3111 (batteries on board road transport). NI’s battery calculations should reference F511 to avoid double-counting with EV batteries (which sit in transport). V2G arbitrage that uses one battery on both sides is not addressed by IEA — NI needs a hybrid disambiguation.
- The 4-digit leaf codes match the granularity of calculation parameterisation. Example: A2231 Building heat pumps splits into air-source / ground-source / water-source / hybrid as named heat-pump types. NI’s habitat skill can use these as the controlled vocabulary for “what kind of heat pump?” without inventing its own taxonomy.
- A4 Agriculture and forestry has NO sub-codes in IEA — single flat category, three illustrative bullets, bioenergy explicitly excluded. This is a structural signal that the IEA does not treat food/agriculture as a peer domain. The NI EDT framework deliberately departs from IEA here: D02 (Smart Food Systems) is a peer domain alongside D01 (Energy), reflecting the community-self-sufficiency framing.
- The IEA classification is not 100% inline with community-SS needs. Six items are explicitly “Out of scope” (walking/cycling, water/wastewater, indoor air quality, pedal electric cycles, transport noise/safety/comfort, and other community-relevant categories). Several community-relevant concepts (rooftop wind, community geothermal usage, solar cooking, biomass stoves) are buried as un-coded bullets without leaf codes. EDT’s D03 Water, D06 Health, D07 Governance, D08 Biotech have no IEA peer at all. The full misalignment catalogue lives in iea_edt_taxonomy_mapping — consult it before using IEA codes as NI vocabulary, and where IEA framing fails NI’s needs, the calculation skill must construct its own term and document the gap.
What the IEA taxonomy does NOT cover:
- Water as a peer domain (no IEA equivalent of EDT D03)
- Health (no IEA equivalent of EDT D06)
- Governance, community economies (no IEA equivalent of EDT D07)
- Biotechnology as a standalone domain (IEA treats biotech only as bioenergy feedstock, C49 Bioenergy NEC)
- Advanced manufacturing as a peer domain (embedded inside each technology group, e.g. C121 solar cell manufacturing)
- Community ownership models, community-finance instruments, participatory co-design
- Indigenous knowledge systems
- Active mobility (walking, cycling — explicitly out of scope)
- Aerobic composting, vermiculture, humanure systems (only anaerobic energy-yielding side via C432)
These are precisely the EDT domains where Neobiome’s framework must construct its own taxonomy — informed by but not constrained by the IEA classification.
Research targets
Documents to retrieve
- RT_114 — IEA Energy Technology Perspectives 2023 (ETP 2023): the primary source of CR_004’s secondhand “5 technology families” characterisation. Retrieval would formally close the mismatch with OT_022’s 9-group RD&D classification by documenting the relationship between the ETP strategic grouping and the formal classification. Available from iea.org.
Research gaps
- None identified — pure taxonomy doc. The misalignment catalogue in iea_edt_taxonomy_mapping surfaces structural gaps but these are EDT-design questions, not IEA-source questions.
Connections
Links to
Concepts (1): IEA ↔ EDT Taxonomy Mapping
Referenced by
Sources (3): OT_116 · OT_117 · RD_004
Concepts (1): IEA ↔ EDT Taxonomy Mapping