Glossary
The following definitions reflect those used by the International Energy Agency (IEA); definitions used by other organisations and publications may vary.
AAU
assigned amount unit
active solar thermal
active solar thermal
ASHP
air-source heat pumps
AST
active solar thermal
Advanced vehicles
covers electric (which are battery powered), plug-in hybrid (which uses two sources of power – most commonly gasoline and electric) and fuel cell models (which convert hydrogen into electricity).
Annex B countries
countries with quantitative targets under the Kyoto Protocol.
Annex I countries
developed countries and countries in transition that have committed under the UNFCCC to undertake emissions reductions activities.
anthropogenic
arising from human activity; for example, anthropogenic greenhouse-gas emissions are those linked to human activity rather than natural sources.
aquifer
an underground water reservoir; if the water contains large quantities of minerals, it is a saline aquifer.
arbitrage
the practice of taking advantage of a price difference between two or more markets.
asset finance
a secured business loan in which the borrower pledges its assets as collateral.
assigned amount unit
the tradable unit under the trading mechanism of the Kyoto Protocol. Each unit allows the country to emit one tonne of CO2 equivalent of any of six greenhouse gases covered by the Protocol.