Kütust

Kütust is the Estonian partitive singular form of the noun kütus, meaning fuel. In everyday language, kütus refers to any substance used to produce energy by burning or chemical reactions, including liquids such as gasoline (bensiin), diesel, and heating oil, as well as gaseous fuels like natural gas and solid fuels such as coal and wood.

The term also covers biofuels such as ethanol and biodiesel, used to reduce greenhouse gas emissions and diversify energy supply. In Estonian, kütust is used in uncountable or indefinite contexts, for example: Kütust on vaja (fuel is needed) and Kütust kulub palju (a lot of fuel is consumed). The related compounds include kütusekulu (fuel consumption) and kütusehind (fuel price).

Impact and policy: The use of kütus has environmental and economic implications. Combustion of fossil kütus emits carbon dioxide and pollutants; efficiency, energy density, and availability determine its role in transport and heating. Policy instruments include fuel taxation, emissions standards, and incentives for alternative or renewable fuels. Supply security is a concern for many economies, especially for imported kütus.

Classification: Broadly, kütus is categorized by origin and application: fossil fuels (petrol, diesel, natural gas, coal), bioderived fuels (bioethanol, biodiesel), and other energy carriers used in specific sectors. In energy discourse, kütust is distinguished from electricity and other energy forms.

Note: While electricity is a major energy carrier, it is generally not described as kütus in Estonian usage.