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Take or Pay Clause (ToP)
A form of purchasing agreement in which a consumer agrees to buy a specified volume of energy over a defined period. Penalty charges are incurred if too little energy is used during the period.

Tariff Structure
Suppliers quote for electricity in numerous different formats. These range from simple one-rated structures (the same price per kW at all times throughout the year) to complex "Seasonal Time of Day - STOD" tariffs, which are multi-rated. i.e. the price changes three, six or eight times a day.

Tariff supply
The 'default' tariff a consumer who has yet to sign a supply contract will be placed on.

Temperature And Pressure
Gas either expands or contracts slightly under varying temperature and pressure. It is also known as the Conversion Factor and usually set at 1.02264. The Conversion Factor is taken into account when converting gas usage from volume to energy.

Terawatt-hour (TWh)
A unit of energy equal to one million kilowatt-hours, 1 TWh is roughly equivalent to the total electricity typically used by 250,000 homes in one year.

Termination Notice
Consumers whose energy supplies are subject to a contract are required to give the incumbent supplier written notice of termination of that contract prior to its end date.

Termination Period
The period prior to the end date of an energy supply contract during or by which termination notice must be given - varies from supplier to supplier.

Therm
A unit of energy measurement. To calculate equivalent value in kWh, multiply by 29.3071.

Thermal efficiency
Quantity of heat produced in relation to fuel input.

Thermal sources of electricity
These include coal, oil, natural gas, nuclear, landfill gas, municipal solid waste and other waste product, straw, coke oven gas and blast furnace gas.

Third Party Intermediary (TPI)
Generic term for service providers that can be employed by business organisations to undertake activities, e.g. supply contracting and energy management activity on their behalf.

Tick
The smallest allowable increment of price movement for a contract.

Tidal Power
The power available from the rise and fall of ocean tides. A tidal power plant works on the principal of a dam or barrage that captures water in a basin at the peak of a tidal flow, then directs it through a hydroelectric turbine as the tide ebbs.

Time Pattern Regimes (TPR)
Codes that state what date and time the meter registers start and finish.

Title (Meter) Owner
This is also referred to as Legal Title Owner. The person or Organisation to which the asset belongs and that makes such assets available for the purpose of the Gas Act Owner.

Tonne (t or mt)
Metric measurement of weight, coal is sold at $US per Tonne.

Tonne of oil equivalent (ToE)
A unit of measurement which enables different fuels to be aggregated and compared.

Top-up
Extra electricity bought by a generator if it produces less than planned.

Transformer
Equipment that is used to change the voltage of an electric current. Transformers can increase or decrease voltage.

Transmission
The transfer of electricity at high voltage from the power stations through wires on pylons to points where it can be distributed to users. This is known as the Grid System.

Transmission Losses (Line Losses)
When transmitting electricity from generator to local distribution network areas some electricity is lost. Specific calculations have to be made by suppliers to determine the level of these losses.

Transmission Use of System (TUoS)
The charges are incurred for transmitting electricity across the National Grid network from the source of generation to the network of local distribution.

Transparency
In relation to a market, the tendency for price signals to be easily visible to all participants and for market pressures to be quickly reflected in price levels.

Transportation Charges
The cost associated with transporting gas through the network, normally collected by the Supplier.

Turbine
A device for converting the flow of a fluid (air, steam, water, or hot gases) into mechanical motion.