Glossary of Energy Terms

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A B C D E F G H I J K L M N O P Q R S T U V W X-Z Acronyms

Note: No entries for Y or Z.

Letter S

SAE VISCOSITY NUMBER - A system established by the Society of Automotive Engineers for classifying crankcase oils and automotive transmission and differential lubricants according to their viscosities.

SCE - The acronym for Southern California Edison Company an electric utility serving the southern California region.

SCHEDULING COORDINATOR - Scheduling coordinators (SCs) submit balanced schedules and provide settlement-ready meter data to the ISO. Scheduling coordinators also:

The PX is considered a scheduling coordinator.

SDG&E - The acronym for San Diego Gas & Electric an electric and natural gas utility serving the San Diego, California, region.

SE (Seasonal Efficiency) - a measure of the percentage of heat from the combustion of gas and from associated electrical equipment which is transferred to the space being heated during a year under specified conditions. California Code of Regulations, Section 2-1602(d)(11).


SECURITIZE - The aggregation of contracts for the purchase of the power output from various energy projects into one pool which then offers shares for sale in the investment market. This strategy diversifies project risks from what they would be if each project were financed individually, thereby reducing the cost of financing. Fannie Mae performs such a function in the home mortgage market.

SEER (Seasonal Energy Efficiency Ratio)--The total cooling output of a central air conditioning unit in Btus during its normal usage period for cooling divided by the total electrical energy input in watt-hours during the same period, as determined using specified federal test procedures. [See California Code of Regulations, Title 20, Section 1602(c)(11)]

SELF-GENERATION - A generation facility dedicated to serving a particular retail customer,usually located on the customer's premises. The facility may either be owned directly by the retail customer or owned by a third party with a contractual arrangement to provide electricity to meet some or all of the customer's load.

SELF-SERVICE WHEELING -- Primarily an accounting policy comparable to net-billing or running the meter backwards. An entity owns generation that produces excess electricity at one site, that is used at another site(s) owned by the same entity. It is given billing credit for the excess electricity (displacing retail electricity costs minus wheeling charges) on the bills for its other sites.


SENSIBLE HEAT - Heat that results in a temperature change.

SERVICE AREA - any contiguous geographic area serviced by the same electric utility.


SET POINT - Scheduled operating level for each generating unit or other resource scheduled to run in the Hour-ahead Schedule.

SETTLEMENT - The process of financial settlement for products and services purchased and sold. Each settlement involves a price and quantity. Both the ISO and PX may perform settlement functions.

SHADING - 1) The protection from heat gains due to direct solar radiation; 2) Shading is provided by (a) permanently attached exterior devices, glazing materials, adherent materials applied to the glazing, or an adjacent building for nonresidential buildings, hotels, motels and highrise apartments, and by (b) devices affixed to the structure for residential buildings. [See California Code of Regulations, Title 24, Section 2-5302]

SHADE SCREEN - A screen affixed to the exterior of a window or other glazed opening, designed to reduce the solar radiation reaching the glazing.

SHADING COEFFICIENT - the ratio of solar heat gain through a specific glazing system to the total solar heat gain through a single layer of clear, double-strength glass.

SIDE FINS - Vertical shading elements mounted on either side of a glazed opening that blocks direct solar radiation from the lower, lateral portions of the sun's path.

SITE - any location on which a facility is constructed or is proposed to be constructed.

SITE ENERGY - The energy consumed at a building location or other end-use site.

SKYLIGHT - Any opening in the roof surface which is glazed with a transparent or translucent material. [See California Code of Regulations, Title 24, Section 2-5302]

SKY TEMPERATURE - The equivalent temperature of the clouds, water vapor, and other atmospheric elements that make up the sky to which a surface can radiate heat.

SMUD - The acronym for the Sacramento Municipal Utility District, an electric utility serving the greater Sacramento, California, region.

SMOG - Originally "smog" meant a mixture of smoke and fog. The definition has expanded to mean air that has restricted visibility due to pollution. Pollution formed in the presence of sunlight is called photochemical smog. According to the U.S. EPA, smog is "a mixture of pollutants, principally ground-level ozone, produced by chemical reactions in the air involving smog-forming chemicals. A major portion of smog-formers come from burning of petroleum-based fuels such as gasoline. Other smog-formers, volatile organic compounds, are found in products such as paints and solvents. Smog can harm health, damage the environment and cause poor visibility. Major smog occurrences are often linked to heavy motor vehicle traffic, sunshine, high temperatures and calm winds or temperature inversion (weather condition in which warm air is trapped close to the ground instead of rising). Smog is often worse away from the source of the smog-forming chemicals, since the chemical reactions that result in smog occur in the sky while the reacting chemicals are being blown away from their sources by winds."

SOLAR CELL - A photovoltaic cell that can convert light directly into electricity. A typical solar cell uses semiconductors made from silicon.

SOLAR COLLECTOR - A component of an active or passive solar system that absorbs solar radiation to heat a transfer medium which, in turn, supplies heat energy to the space or water heating system.

SOLAR ENERGY - Heat and light radiated from the sun.

SOLAR ENERGY RESEARCH INSTITUTE (SERI) -- Established in 1974 and funded by the federal government, the institute's general purpose is to support U.S. Department of Energy's solar energy program and foster the widespread use of all aspects of solar technology, including photovoltaics, solar heating and cooling, solar thermal power generation, wind ocean thermal conversion and biomass conversion.

SOLAR HEAT GAIN - Heat added to a space due to transmitted and absorbed solar energy.

SOLAR HEAT GAIN FACTOR - An estimate used in calculating cooling loads of the heat gain due to transmitted and absorbed solar energy through 1/8"-thick, clear glass at a specific latitude, time and orientation.

SOLAR HEATING AND HOT WATER SYSTEMS - Solar heating or hot water systems provide two basic functions: (a) capturing the sun's radiant energy, converting it into heat energy, and storing this heat in insulated storage tank(s); and (b) delivering the stored energy as needed to either the domestic hot water or heating system. These components are called the collection and delivery subsystems.

SOLAR IRRADIATION - The amount of radiation, both direct and diffuse, that can be received at any given location.

SOLAR POWER - Electricity generated from solar radiation.

SOLAR RADIATION - Electromagnetic radiation emitted by the sun.

SOLAR SATELLITE POWER - A proposed process of using satellites in geosynchronous orbit above the earth to capture solar energy with photovoltaic cells, convert it to microwave energy, beam the microwaves to earth where they would be received by large antennas, and changed from microwave into usable electricity.

SOLAR THERMAL POWER PLANT - means a thermal powerplant in which 75 percent or more of the total energy output is from solar energy and the use of backup fuels, such as oil, natural gas, and coal, does not, in the aggregate, exceed 25 percent of the total energy input of the facility during any calendar year period.

SOLAR THERMAL - The process of concentrating sunlight on a relatively small area to create the high temperatures needs to vaporize water or other fluids to drive a turbine for generation of electric power.

SOURCE ENERGY - All the energy used in delivering energy to a site, including power generation and transmission and distribution losses, to perform a specific function, such as space conditioning, lighting, or water heating. Approximately three watts (or 10.239 Btus) of energy is consumed to deliver one watt of usable electricity.

SPECIAL CONTRACTS - Any contract that provides a utility service under terms and conditions other than those listed in the utility's tariffs. For example, an electric utility may enter into an agreement with a large customer to provide electricity at a rate below the tariffed rate in order to prevent the customer from taking advantage of some other option that would result in the loss of the customer's load. This generally allows that customer to compete more effectively in their product market.

SPECIFIC HEAT - In English units, the quantity of heat, in Btu, needed to raise the temperature of one pound of material one degree Fahrenheit.


SPLIT-THE-SAVINGS (Electric Utility) - The basis for settling economy-energy transactions between utilities. The added costs of the supplier are subtracted from the avoided costs of the buyer, and the difference is evenly divided.

STANDBY LOSS - A measure of the losses from a water heater tank. When expressed as a percentage, standby loss is the ratio of heat loss per hour to the heat content of the stored water above room temperature. When expressed in watts, standby loss is the heat lost per hour, per square foot of tank surface area. [See California Code of Regulations, Title 20, Section 1602(f)(5)]

STEADY STATE EFFICIENCY - A performance rating for space heaters; a measure of the percentage of heat from combustion of gas which is transferred to the space being heated under specified steady state conditions. [See California Code of Regulations, Title 20, Section 1602(e)(13)]

STEAM ELECTRIC PLANT - A power station in which steam is used to turn the turbines that generate electricity. The heat used to make the steam may come from burning fossil fuel, using a controlled nuclear reaction, concentrating the sun's energy, tapping the earth's natural heat or capturing industrial waste heat.

STIRLING ENGINE - An external combustion engine that converts heat into useable mechanical energy (shaftwork) by the heating (expanding) and cooling (contracting) of a captive gas such as helium or hydrogen.

STORAGE TYPE WATER HEATER - A water heater that heats and stores water at a thermostatically controlled temperature for delivery on demand. [See California Code of Regulations, Title 20, Section 1602(f)(6)]

STRANDED BENEFITS - Public interest programs and goals which could be compromised or abandoned by a restructured electric industry. These potential "stranded benefits" might include: environmental protection, fuel diversity, energy efficiency, low-income ratepayer assistance, and other types of socially beneficial programs.

STRANDED COSTS/STRANDED ASSETS - See embedded Costs Exceeding Market Prices.

STRATEGIC PETROLEUM RESERVE - The strategic petroleum reserve consists of government owned and controlled crude oil stockpiles stored at various locations in the Gulf Coast region of the country. These reserves can be drawn down in response to sever oil supply disruptions. The target is to have a reserve of 750 million barrels of oil. Use of the reserve must be authorized by the President of the United States.

SUBSTATION - A facility that steps up or steps down the voltage in utility power lines. Voltage is stepped up where power is sent through long-distance transmission lines. it is stepped down where the power is to enter local distribution lines.

SUNK COST - In economics, a sunk cost is a cost that has already been incurred, and therefore cannot be avoided by any strategy going forward.

SUPERCONDUCTOR - A synthetic material that has very low or no electrical resistance. Such experimental materials are being investigated in laboratories to see if they can be created at near room temperatures. If such a superconductor can be found, electrical transmission lines with no little or no resistance may be built, thus conserving energy usually lost in transmission. Superconductors could also have uses in computer chips, solid state devices and electrical motors or generators.

SUPERTANDKER - A very large ship designed to transport more than 500,000 deadweight tonnage of oil.

SUPPLY BID - A bid into the PX indicating a price at which a seller is prepared to sell energy or ancillary services.

SUPPLY-SIDE - Activities conducted on the utility's side of the customer meter. Activities designed to supply electric power to customers, rather than meeting load though energy efficiency measures or on-site generation on the customer side of the meter.

SURPLUS - (Electric utility) Excess firm energy available from a utility or region for which there is no market at the established rates.

SUSTAINED ORDERLY DEVELOPMENT - A condition in which a growing and stable market is identified by orders that are placed on a reliable schedule. The orders increase in magnitude as previous deliveries and engineering and field experience lead to further reductions in costs. The reliability of these orders can be projected many years into the future, on the basis of long-term contracts, to minimize market risks and investor exposure. (See also "Commercialization.")

SWRTA - The Southwest Regional Transmission Association. a subregional RTG within WRTA, and awaiting FERC approval.

SYNCHROPHASORS - Precise grid measurements available from monitors called phasor measurement units (PMUs). PMU measurements are taken at high speed (typically 30 observations per second - compared to one every 4 seconds using conventional technology.) Each measurement is time-stamped according to a common time reference. Time stamping allows synchrophasors from different utilities to be time-aligned (or "synchronized") and combined together, providing a precise and comprehensive view of the entire interconnection. Synchrophasors enable a better indication of grid stress and can be used to trigger corrective actions to maintain reliability. (Source: North American Synchro Phasor Initiative)

SYNCRUDE - Synthetic crude oil made from coal of from oil shale.

SYNFUEL - Synthetic gas or synthetic oil. Fuel that is artificially made as contrasted to that which is found in nature. Synthetic gas made from coal is considered to be more economical and easier to produce than synthetic oil. When natural gas supplies in the earth are being depleted, it is expected that synthetic gas will be able to be used widely as a substitute fuel.

SYNGAS - Synthetic gas make from coal.

SYSTEM - A combination of equipment and/or controls, accessories, interconnecting means and terminal elements by which energy is transformed to perform a specific function, such as climate control, service water heating, or lighting. [See California Code of Regulations, Title 24, Section 2-5302]

SYSTEM INTEGRATION (OF NEW TECHNOLOGIES) - The successful integration of a new technology into the electric utility system by analyzing the technology's system effects and resolving any negative impacts that might result from its broader use.

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