Glossary of Terms - T

• Tank Train - A procedure in the rail shipment of crude oil, refined products, and other liquids developed by General American Transportation (GATX). "Tank Train" tank cars are interconnected, which permits loading and unloading of the entire train of cars from one connection.
• Target Market - A specific group of people or geographical area that has been identified as the primary buyers of a product or service.
• Tariff - A schedule of rates or charges permitted a common carrier or utility; pipeline tariffs are the charges made by pipelines for transporting crude oil, refined products, or natural gas from an origin to a destination.
• Tax Credits - Credits established by the federal and state government to assist the development of the alternative energy industry.
• Technical Analysis - An approach to forecasting commodity prices which examines patterns of price change, rates of change, and changes in trading volume and open interest, without regard to underlying fundamental market conditions.
• Temperature Coefficient (of a solar photovoltaic cell) - The amount that the voltage, current, and/or power output of a solar cell changes due to a change in the cell temperature.
• Temperature Humidity Index - An index that combines sensible temperature and air humidity to arrive at a number that closely responds to the effective temperature; used to relate temperature and humidity to levels of comfort.
• Tennessee Valley Authority (TVA) - A federal agency established in 1933 to develop the Tennessee river valley region of the southeastern U.S., and which is now nation's largest power producer.
• Term Trading - In the power markets, equals trading electricity rights and generation for delivery a day ahead or more - for a specified term.
• Theoretical Value - An option's value generated by a mathematical model given certain prior assumptions about the term of the option, the characteristics of the underlying futures contract, and prevailing interest rates.
• Therm - A unit of heat containing 100,000 British thermal units (Btu). 100,000 British thermal units. A dekatherm is 1 million Btus.
• Thermal Balance Point - The point or outdoor temperature where the heating capacity of a heat pump matches the heating requirements of a building.
• Thermal Efficiency - A measure of the efficiency of converting a fuel to energy and useful work; useful work and energy output divided by higher heating value of input fuel times 100 (for percent).
• Thermal Energy - The energy developed through the use of heat energy.
• Thermal Energy Storage - The storage of heat energy during utility off-peak times at night, for use during the next day without incurring daytime peak electric rates.
• Thermal Envelope Houses - An architectural design (also known as the double envelope house), sometimes called a "house-within-a-house," that employs a double envelope with a continuous airspace of at least 6 to 12 inches on the north wall, south wall, roof, and floor, achieved by building inner and outer walls, a crawl space or sub-basement below the floor, and a shallow attic space below the weather roof. The east and west walls are single, conventional walls. A buffer zone of solar-heated, circulating air warms the inner envelope of the house. The south-facing airspace may double as a sunspace or greenhouse.
• Thermal Mass - Materials that store heat.
• Thermal Resistance (R-Value) - This designates the resistance of a material to heat conduction. The greater the R-value the larger the number.
• Thermocouple - A device consisting of two dissimilar conductors with their ends connected together. When the two junctions are at different temperatures, a small voltage is generated.
• Thermodynamic Cycle - An idealized process in which a working fluid (water, air, ammonia, etc) successively changes its state (from a liquid to a gas and back to a liquid) for the purpose of producing useful work or energy, or transferring energy.
• Thermodynamics - A study of the transformation of energy from one form to another, and its practical application. (see Law(s) of Thermodynamics above).
• Thermoelectric Conversion - The conversion of heat into electricity by the use of thermocouples.
• Thermography - A building energy auditing technique for locating areas of low insulation in a building envelope by means of a thermographic scanner.
• Thermophotovoltaic Cell - A device where sunlight concentrated onto a absorber heats it to a high temperature, and the thermal radiation emitted by the absorber is used as the energy source for a photovoltaic cell that is designed to maximize conversion efficiency at the wavelength of the thermal radiation.
• Thermopile - A large number of thermocouples connected in series.
• Thermostat - A device used to control temperatures; used to control the operation of heating and cooling devices by turning the device on or off when a specified temperature is reached.
• Thermosyphon - The natural, convective movement of air or water due to differences in temperature. In solar passive design a thermosyphon collector can be constructed and attached to a house to deliver heat to the home by the continuous pattern of the convective loop (or thermosyphon).
• Thermosyphon (Solar) Systems - Thermosyphon systems use a separate storage tank located above the collector. Liquid warmed in the collector rises naturally above the collector, where it is kept until it is needed. The liquid can be either water or a glycol solution. If the fluid is water, freeze protection is provided by electric heat. If the fluid is glycol, the heat from the glycol is transferred to water in the storage tank.
• Theta - The sensitivity of an option's value to a change in the amount of time to expiration.
• Three Phase Line - This is capable of carrying heavy loads of electricity, usually to larger commercial customers.
• Three-phase Current - Alternating current in which three separate pulses are present, identical in frequency and voltage, but separated 120 degrees in phase.
• Throughput - 1) A term used to describe the total volume of raw materials that are processed by a plant such as an oil refinery in a given period. 2) The total volume of crude oil and refined products that are handled by a tank farm, pipeline, or terminal loading facility.
• Tick - A minimum change in price, up or down.
• 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 the water through a hydroelectric turbine as the tide ebbs.
• Time Spread - The selling of a nearby option and buying of a more deferred option with the same strike price.
• Time Value - Part of the options premium which reflects the excess over the intrinsic value, or the entire premium if there is no intrinsic value. At given price levels, the option's time value will decline until expiration. It is this decrease in time value that makes options a wasting asset.
• Time-of-Use Rates - Electricity prices that vary depending on the time periods in which the energy is consumed. In a time-of-use rate structure, higher prices are charged during utility peak-load times. Such rates can provide an incentive for consumers to curb power use during peak times.
• Timer - A device that can be set to automatically turn appliances (lights) off and on at set times.
• Tip Speed Ratio - In reference to a wind energy conversion device's blades, the difference between the rotational speed of the tip of the blade and the actual velocity of the wind.
• Tipping Fee - A credit received by municipal solid waste companies for accepting and disposing of solid waste.
• Ton (of Air Conditioning) - A unit of air cooling capacity; 12,000 Btu per hour.
• Topping-cycle - A means to increase the thermal efficiency of a steam electric generating system by increasing temperatures and interposing a device, such as a gas turbine, between the heat source and the conventional steam-turbine generator to convert some of the additional heat energy into electricity.
• Torque (Motor) - The turning or twisting force generated by an electrical motor in order for it to operate.
• Total DSM Cost - Total utility and nonutility costs.
• Total DSM Programs - Refers to the total net effects of all the utilityÌs DSM programs. For the purpose of this survey, it is the sum of the effects for Energy Efficiency, Direct Load Control, Interruptible Load, Other Load Management, Other DSM Programs, and Load Building. Net growth in energy or load effects should be reported as a negative number, shown with a minus sign.
• Total Heat - The sum of the sensible and latent heat in a substance or fluid above a base point, usually 32 degrees Fahrenheit.
• Total Incentives - The incentive a utility offers is expressed as a percentage of the technology cost. The utility can assume any level between 0 and 100 percent. A value greater than 100 percent is possible if the utility decides to pay for all the equipment and give a rebate as an additional incentive. You can calculate the required incentive by setting the participant test to one by using the following formula: Total Incentives = (Technology Costs - Bill Reductions)/2.
• Total Incident Radiation - The total radiation incident on a specific surface area over a time interval.
• Total Internal Reflection - The trapping of light by refraction and reflection at critical angles inside a semiconductor device so that it cannot escape the device and must be eventually absorbed by the semiconductor.
• Total Nonutility Costs - Cash expenditures incurred through participation in a DSM program that are not reimbursed by the utility.
• Total Resource Cost (TRC) Test - A ratio used to assess the cost effectiveness of a demand-side management program. Although this economic desirability test provides information about the relative merits of different DSM programs, several important issues are not addressed in this analysis. First, this cost-effectiveness test does not indicate the level of program participation that will be achieved. Second, the most cost-effective mix of DSM technologies is not determined by this test because this methodology only evaluates one specific measure at a time. Finally, these tests are static; they do not include a feedback mechanism to account for changes in demand due to the DSM program. The TRC Test measures the ratio of total benefits to the costs incurred by both the utility and the participant. The TRC test is applicable to conservation, load management, and fuel substitution technologies. For fuel substitution technologies, the test compares the impact from the fuel not selected to the impact of the fuel that is chosen as a result of implementing the technologies. The TRC Test includes benefits occurring to both participants and nonparticipants. Benefits include avoided supply costs (I.e. transmission, distribution, generation, and capacity costs). Costs include those incurred by both the utility and program participant.
• Total Utility Costs - Refers to the sum of the total Direct and Indirect Utility Costs for the year. Utility costs should reflect the total cash expenditures for the year, reported in nominal dollars, that flowed out to support DSM programs. They should be reported in the year they are incurred, regardless of when the actual effects occur.
• Tower - A steel structure found along transmission lines which is used to support conductors.
• Tracking PV Array - PV array that follows the path of the sun to maximize the solar radiation incident on the PV surface. The two most common orientations are (1) one axis where the array tracks the sun east to west and (2) two-axis tracking where the array points directly at the sun at all times. Tracking arrays use both the direct and diffuse sunlight. Two-axis tracking arrays capture the maximum possible daily energy.
• Tracking Solar Array - A solar energy array that follows the path of the sun to maximize the solar radiation incident on the PV surface. The two most common orientations are (1) one axis where the array tracks the sun east to west and (2) two-axis tracking where the array points directly at the sun at all times. Tracking arrays use both the direct and diffuse sunlight. Two-axis tracking arrays capture the maximum possible daily energy.
• Trade - The act or an instance of buying or selling; transaction. An agreement between a buyer and a seller to exchange an asset for payment. An exchange of one thing for another. Participating in market structures to procure assets, layoff risk, negotiate price or sell commodities.
• Trade House - A firm which deals in the physical commodity.
• Trading - Buying and Selling.
• Trading Volume - The number of contracts that change hands during a specified period of time.
• Trailing Edge - The part of a wind energy conversion device blade, or airfoil, that is the last to contact the wind.
• Transfer - To move electric energy from one utility system to another over transmission lines.
• Transformer - An electromagnetic device that changes the voltage of alternating current electricity. It consists of an induction coil having a primary and secondary winding and a closed iron core.
• Transition Charge - A charge on every customer's bill designed to recover an electric utility's transition or stranded costs as determined by a Public Utility Commission.
• Transition Costs - Costs incurred by electric utilities to meet obligations, which required the utilities to meet current and future load demand. The utilities ensured sufficient power generating capacity by building additional power plants, whose debts are currently recovered through a regulated rate of return that would not continue in a competitive marketplace. They could be recovered with a special charge during the transition to competition.
• Transmission - The movement or transfer of electric energy over an interconnected group of lines and associated equipment between points of supply and points at which it is transformed for delivery to consumers, or is delivered to other electric systems. Transmission is considered to end when the energy is transformed for distribution to the consumer.
• Transmission and Distribution (T&D) System - An interconnected group of electric transmission lines and associated equipment for the movement or transfer or electric energy in bulk between points of supply and points at which it is transformed for delivery to the ultimate customers.
• Transmission and Distribution Losses - The losses that result from inherent resistance in electrical conductors and transformation inefficiencies in distribution transformers in a transmission and distribution network.
• Transmission Charge - Part of the basic service charges on every customer's bill for transporting electricity from the source of supply to the electric distribution company. Public Utility Commissions regulate retail transmission prices and services. The charge will vary with source of supply.
• Transmission Company - Company that transports gas for resale on its own behalf or transports gas for others. Also known as a pipeline company.
• Transmission Lines - Heavy wires that carry large amounts of electricity over long distances from a generating station to places where electricity is needed. Transmission lines are held high above the ground on tall towers called transmission towers.
• Transmission System (Electric) - An interconnected group of electric transmission lines and associated equipment for moving or transferring electric energy in bulk between points of supply and points at which it is transformed for delivery over the distribution system lines to consumers, or is delivered to other electric systems.
• Transparent Price - The most recent price contract available to any buyer or seller in the market.
• Traveling Grate - A furnace grate that moves fuel through the combustion chamber
• Trend - The general direction of price movement.
• Triangular Flags - Chart patterns of the price movement of a commodity when the market consolidates sideways. The price patterns are used by technical analysts to try to recognize changes in a price trend.
• Trickle (Solar) Collector - A type of solar thermal collector in which a heat transfer fluid drips out of header pipe at the top of the collector, runs down the collector absorber and into a tray at the bottom where it drains to a storage tank.
• Trickle Charge - A charge at a low rate, balancing through self-discharge losses, to maintain a cell or battery in a fully charged condition.
• True Power - The actual power rating that is developed by a motor before losses occur.
• Tube-In-Plate-Absorber - A type of solar thermal collector where the heat transfer fluid flows through tubes formed in the absorber plate.
• Tube-Type Collector - A type of solar thermal collector that has tubes (pipes) that the heat transfer fluid flows through that are connected to a flat absorber plate.
• Tunneling - Quantum mechanical concept whereby an electron is found on the opposite side of an insulating barrier without having passed through or around the barrier.
• Turbine - A machine for generating rotary mechanical power from the energy of a stream of fluid (such as water, steam, or hot gas). Turbines convert the kinetic energy of fluids to mechanical energy through the principles of impulse and reaction, or a mixture of the two.
• Turn Down Ratio - The ratio of a boiler's or gasifier's maximum output to its minimum output.
• Type of Option - Either puts or calls.