The following definitions reflect those used by the International Energy Agency (IEA); definitions used by other organisations and publications may vary.


transmission and distribution (of electricity)


tertiary amyl methyl ether


Energy Training & Capacity Building Programme (of the IEA)


Technology Collaboration Programmes, also known as Implementing Agreements, Multilateral Technology Initiatives or Energy Technology Initiatives (of the IEA). List of programmes as of 2016:

  • Advanced Fuel Cells (AFC TCP)
  • Advanced Materials for Transportation (AMT TCP)
  • Advanced Motor Fuels (AMF TCP)
  • Bioenergy (Bioenergy TCP)
  • Buildings and Communities (EBC TCP)
  • Clean and Efficient Combustion (Combustion TCP)
  • Clean Coal Centre (CCC TCP)
  • Climate Technology Initiative (CTI TCP)
  • Co-operation on Tokamak Programmes (CTP TCP)
  • Demand-Side Management (DSM TCP)
  • District Heating and Cooling, including the Integration of Combined Heat and Power (DHC TCP)
  • Energy Efficient End-Use Equipment (4E TCP) 
  • Energy Storage (ECES TCP)
  • Energy Technology Systems Analysis (ETSAP TCP)
  • Enhanced Oil Recovery (EOR TCP)
  • Environmental, Safety and Economic Aspects of Fusion Power (ESEFP TCP)
  • Fluidized Bed Conversion (FBC TCP)
  • Fusion Materials (FM TCP)
  • Gas and Oil (GOTCP)
  • Geothermal (Geothermal TCP)
  • Greenhouse Gas R&D (GHG TCP) 
  • Heat Pumping Technologies (HPT TCP)
  • High-Temperature Superconductivity (HTS TCP)
  • Hybrid and Electric Vehicles (HEV TCP)
  • Hydrogen (Hydrogen TCP)
  • Hydropower (Hydropower TCP)
  • Industrial Technologies and Systems (IETS TCP)
  • Nuclear Technology of Fusion Reactors (NTFR TCP)
  • Ocean Energy Systems (OES TCP)
  • Photovoltaic Power Systems (PVPS TCP)
  • Plasma Wall Interaction (PWI TCP)
  • Renewable Energy Technology Deployment (RETD TCP)
  • Reversed Field Pinches (RFP TCP)
  • Smart Grids (ISGAN TCP)
  • Solar Heating and Cooling (SHC TCP)
  • SolarPACES  (SolarPACES TCP)
  • Spherical Tori (ST TCP)
  • Stellarator-Heliotron Concept (SH TCP)
  • Wind Energy Systems (Wind TCP)


total final consumption


tradable green certificate


total primary energy demand


total primary energy supply



technology transfer

(two definitions) the process of converting scientific findings from research laboratories into useful products by the private sector; second definition is used more in economic development literature and involves cross-border transmission of technology from one country to another.

total final consumption

the sum of consumption by the different end-use sectors. TFC is broken down into energy demand in the following sectors: industry, transport, buildings (including residential and services) and other (including agriculture and non-energy use). It excludes international marine and aviation bunkers, except at world level where it is included in the transport sector.

total primary energy demand

represents domestic demand only and is broken down into power generation, other energy sector and total final consumption.

total primary energy supply

equivalent to total primary energy demand. TPES represents inland demand only and, except for world energy demand, excludes international marine and aviation bunkers.

traditional biomass

the use of fuelwood, charcoal, animal dung and agricultural residues in stoves with very low efficiencies.


refers under IEA statistical purposes to fuels and electricity used in the transport of goods or persons within the national territory irrespective of the economic sector within which the activity occurs. This includes fuel and electricity delivered to vehicles using public roads or for use in rail vehicles; fuel delivered to vessels for domestic navigation; fuel delivered to aircraft for domestic aviation; and energy consumed in the delivery of fuels through pipelines. Fuel delivered to international marine and aviation bunkers is presented only at the world level and is excluded from the transport sector at the domestic level.


tonne = metric tonne = 1 000 kg


tonnes per year


thousand cubic feet


trillion cubic metres






terawatt hour