Glossary - Letter T

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Vessel used to transport bulk liquids in huge tanks. The best-known tankers are oil tankers, which carry crude oil.

Tectonic Plate

Rigid fragment of the lithosphere (the Earth’s crust and upper mantle) that "floats" on the asthenosphere, which is mechanically weaker. Tectonic plates move more or less independently, leading to collisions that form mountain ranges, divergence that forms rifts or oceanic ridges, subduction that forms deep oceanic trenches, and strike-slips. Also called lithospheric plate.

Tetrahydrothiophene (THT) or Thiolane

Unpleasant-smelling gas used in very small quantities as an additive in commercial gas, which would otherwise be odorless.

Thermal Collector (Solar)

Device used to absorb solar heat and then release it.

Thermal Conductivity

A measure of the ability of a substance to conduct heat. It is the quantity of heat transferred per unit time and per unit surface area at a temperature gradient of 1 kelvin per meter (1 K/m).

Thermal Inertia

The resistance of a material to temperature change. The higher its thermal inertia, the longer a material will take to reach a temperature at equilibrium with its surroundings.

Thermal Resistance

Ability of a substance to resist the flow of heat. Good thermal insulators have high thermal resistance.


Device in which a heat transfer fluid such as gas or water flows naturally from bottom to top due to a temperature differential. In the thermosiphon of a thermodynamic solar system, for example, hot water (which is light) naturally rises towards the place where it will be stored or used. Cold water, however, is heavier and moves downward.


Domestic excise tax on energy products in France that replaced the domestic excise tax on petroleum products (TIPP) on January 1, 2011.

Tidal Power

Tidal power involves harnessing the energy of tidal currents or of the differences in sea level between high and low tide. Several tidal power stations have been commissioned around the world since the first was opened on the Rance River in Brittany (France) in 1966.

Tidal Power Plant

A power-generating station that harnesses the energy of tidal currents. The difference in height (head) between high and low tides is used to drive hydroelectric turbines. Current power plants use the potential energy of water stored behind a dam during a rising tide, with their turbines operating during falling and low tides. However, there are promising projects involving tidal turbine plants that make direct use of the kinetic energy of both rising and falling tidal currents.

Tidal Range

The maximum vertical difference between high and low tide. Tidal ranges vary depending on the time of year and geographical location. France and Canada boast the world’s largest tidal ranges, in the Mont Saint-Michel Bay and the Bay of Fundy respectively.

Tidal Turbine

A tidal turbine is a hydraulic turbine that is powered by natural ocean, tidal or river currents. It converts the current's kinetic energy (motion) into electric power.


Toluene, also known as methylbenzene or phenylmethane, is an aromatic hydrocarbon (member of the benzene family) with the chemical formula CH3-C6H5. Toluene is used as a solvent, especially in paint. It also raises the octane rating of fuel. Toluene is used in a number of industrial processes, notably in the manufacture of rubber, phenol and TNT.

Ton of Coal Equivalent (tce)

Unit of energy measurement corresponding to the energy produced by the combustion of a ton of coal. 1 ton of coal equivalent = 29,307 gigajoules (GJ).

Ton of Oil Equivalent (toe)

Unit of energy measurement corresponding to the energy produced by the combustion of a ton of oil. The unit was developed to be able to compare the energy consumption and production of a country or region, regardless of the energy sources used. 1 ton of oil equivalent = 41.868 gigajoules (GJ) or 11,630 kWh.

Topping (Refining)

Another name for atmospheric distillation.

Tower (Wind Energy)

One of the parts of a wind turbine. The tower is usually made of metal, occasionally of concrete, and supports the nacelle and rotor unit that produces electricity. It is anchored to a concrete base that ranges from 100 to 300 square meters in size and descends several meters into the ground, depending on the type of turbine and soil. The extensive base ensures that the wind turbine is stable.


Person who buys and sells financial products, such as shares, bonds, options and derivatives, in a financial market for gain. In the petroleum industry, traders buy the oil that refineries need. They also trade in future markets in order to generate future profits.


The buying and selling of products in financial markets.

Transportation Fuel

The heat released during the combustion of liquids such as gasoline, gases such as autogas LPG and solids such as propellants is used to power combustion engines, which are engines in which chemical energy is converted into mechanical energy.


Treating is all of the refining processes intended to remove unwanted compounds (contaminants) from and improve the properties of certain products so that they meet applicable standards.

Trente Glorieuses

The 30 years from 1945 to 1974 during which France — and most other developed countries — experienced significant economic growth. They came to an end with the first oil crisis.