The following definitions reflect those used by the International Energy Agency (IEA); definitions used by other organisations and publications may vary.
group of 20 finance ministers and central bank governors. The group is made up of all Group of Eight members, plus Argentina, Australia, Brazil, China, India, Indonesia, Mexico, Saudi Arabia, South Africa, South Korea and Turkey. The European Union is the 20th member.
Group of Seven industrialised nations – Canada, France, Germany, Italy, Japan, the United Kingdom and the United States. Known as Group of Eight until 2014, when Russia's membership was suspended. The European Union also participates.
gross domestic product
gross fixed capital formation
geothermal heat pumps
Green Investment Scheme
geographic information systems
The Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation Model
ground-source heat pumps
includes natural gas (both associated and non-associated with petroleum deposits, but excluding natural gas liquids) and gas-works gas.
a process featuring reaction of methane with oxygen or steam to produce syngas (a mixture of hydrogen and carbon monoxide) followed by synthesis of liquid products (such as diesel and naphtha) from the syngas using Fischer-Tropsch catalytic synthesis. The process is similar to those used in coal-to-liquids or biomass-to-liquids.
energy available as heat emitted from within the earth’s crust, usually in the form of hot water or steam.
the observed increased of the global average temperature as a result of human and other activities, including through the increased concentration of greenhouse gases such as CO2 from energy.
amount of electricity produced by green methods;set by regulations but can be traded.
greenhouse gases (such as water vapour, CO2, methane, etc) in the atmosphere absorb and re-emit heat being radiated from the earth, trapping warmth.
referring to gases that contribute to the greenhouse effect by absorbing infrared radiation (heat). Anthropogenic emissions of six greenhouse gases are covered by the Kyoto Protocol.
a country’s annual economic output.
gallon (US or UK)
gramme of coal equivalent
gramme of carbon dioxide per kilometre
gramme of carbon dioxide per kilowatt-hour
giga-hectare (1 hectare x 109)
gigajoule (1 joule x 109)
gigajoule per tonne
gigatonne (1 tonne x 109)
gigatonne of carbon-dioxide equivalent (using 100-year global warming potentials for different greenhouse gases)
gigawatt (1 Watt x 109)
gigawatt thermal (1 Watt x 109)