Glossary of Energy Terms
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Note: No entries for Y or Z.
R-VALUE -- A unit of thermal resistance used for comparing insulating values of different material. It is basically a measure of the effectiveness of insulation in stopping heat flow. The higher the R-value number, a material, the greater its insulating properties and the slower the heat flow through it. The specific value needed to insulate a home depends on climate, type of heating system and other factors.
RADIANT ENERGY -- Energy transferred by the exchange of electromagnetic waves from a hot or warm object to one that is cold or cooler. Direct contact with the object is not necessary for the heat transfer to occur.
RANKINE CYCLE -- The steam-Rankine cycle employing steam turbines has been the mainstay of utility thermal electric power generation for many years. The cycle, as developed over the years uses superheat, reheat and regeneration. Modern steam Rankine systems operate at a cycle top temperature of about 1,073 degrees Celsius with efficiencies of about 40 percent.
RATE-BASING -- refers to practice by utilities of allotting funds invested in utility Research Development Demonstration and Commercialization and other programs from rate-payers, as opposed to allocating these costs to shareholders.
RECOVERY EFFICIENCY -- (Thermal efficiency) Ia water heater, a measure of the percentage of heat from the combustion of gas which is transferred to the water as measured under specified test conditions. California Code of Regulations, Section 2- 1602(e)(7).
REFINERY -- A facility that separates crude oil into varied oil products. The refinery uses progressive temperature changes to separate by vaporizing the chemical components of crude oil that have different boiling points. These are distilled into usable products such as gasoline, fuel oil, lubricants and kerosene.
REFORMULATED GASOLINE (RFG) -- A cleaner-burning gasoline that has had its compositions and/or characteristics altered to reduce vehicular emissions of pollutants. It was sold in California beginning in 1996 with the oxygenate additive MTBE.
RDF (REFUSE DERIVED FUEL) -- The fuel component of municipal solid waste (MSW), which is the by-product of shredding MSW to a uniform size, screening out oversized materials and isolating ferrous material in magnetic separation. The resulting RDF can be burned as a fuel source.
REGULATION -- The service provided by generating units equipped and operating with automatic generation controls that enables the units to respond to the ISO's direct digital control signals to match real-time demand and resources, consistent with established operating criteria.
REGULATORY MUST-RUN GENERATION -- Utilities will be allowed to generate electricity when hydro resources are spilled for fish releases, irrigation, and agricultural purposes, and to generate power that is required by federal or state laws, regulations, or jurisdictional authorities. Such requirements include hydrological flow requirements, irrigation and water supply, solid-waste generation, or other generation contracts in effect on December 20, 1995.
REGULATORY MUST-TAKE GENERATION -- Utilities will be allowed to generate electricity from those resources -- identified by the CPUC -- that are not subject to competition. These resources will be scheduled with the ISO on a must-take basis. Regulatory Must-Take Generation includes QF generating units under federal law, nuclear units and pre-existing power-purchase contracts that have minimum-take provisions.
RELIABILITY -- Electric system reliability has two components-- adequacy and security. Adequacy is the ability of the electric system to supply the aggregate electrical demand and energy requirements of the customers at all times, taking into account scheduled and unscheduled outages of system facilities. Security is the ability of the electric system to withstand sudden disturbances such as electric short circuits or unanticipated loss of system facilities.
- Required to meet the reliability criteria for interconnected systems operation.
- Needed to meet load (demand) in constrained areas.
- Needed to provide voltage or security support of the ISO or of a local area.
RENEWABLE ENERGY -- Resources that constantly renew themselves or that are regarded as practically inexhaustible. These include solar, wind, geothermal, hydro and wood. Although particular geothermal formations can be depleted, the natural heat in the earth is a virtually inexhaustible reserve of potential energy. Renewable resources also include some experimental or less-developed sources such as tidal power, sea currents and ocean thermal gradients.
RENEWABLE RESOURCES -- Renewable energy resources are naturally replenishable, but flow-limited. They are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. Some (such as geothermal and biomass) may be stock-limited in that stocks are depleted by use, but on a time scale of decades, or perhaps centuries, they can probably be replenished. Renewable energy resources include: biomass, hydro, geothermal, solar and wind. In the future they could also include the use of ocean thermal, wave, and tidal action technologies. Utility renewable resource applications include bulk electricity generation, on-site electricity generation, distributed electricity generation, non-grid-connected generation, and demand-reduction (energy efficiency) technologies.
REREGULATION -- The design and implementation of regulatory practices to be applied to the remaining regulated entities after restructuring of the vertically-integrated electric utility. The remaining regulated entities would be those that continue to exhibit characteristics of a natural monopoly, where imperfections in the market prevent the realization of more competitive results,and where, in light of other policy considerations, competitive results are unsatisfactory in one or more respects. Re-regulation could employ the same or different regulatory practices as those used before restructuring.
RESEARCH AND DEVELOPMENT (R&D) -- Research is the discovery of fundamental new knowledge. Development is the application of new knowledge to develop a potential new service or product. Basic power sector R&D is most commonly funded and conducted through the Department of Energy (DOE), its associated government laboratories, university laboratories,the Electric Power Research Institute (EPRI), and private sector companies.
RESERVE GENERATING CAPACITY -- The amount of power that can be produced at a given point in time by generating units that are kept available in case of special need. This capacity may be used when unusually high power demand occurs, or when other generating units are off-line for maintenance, repair or refueling.
RESIDUE -- any organic matter left as residue, such as agricultural and forestry residue, including, but not limited to, conifer thinnings, dead and dying trees, commercial hardwood, noncommercial hardwoods and softwoods, chaparral, burn, mill, agricultural field, and industrial residues, and manure.
RESISTANCE (ELECTRICAL) -- The ability of all conductors of electricity to resist the flow of current, turning some of it into heat. Resistance depends on the cross section of the conductor (the smaller the cross section, the greater the resistance) and its temperature (the hotter the cross section, the greater its resistance).
RESISTANCE (THERMAL) --The reciprocal of thermal conductance. See R-VALUE.
RESOURCE EFFICIENCY -- The use of smaller amounts of physical resources to produce the same product or service. Resource efficiency involves a concern for the use of all physical resource sand materials used in the production and use cycle, not just the energy input.
RESTRUCTURING -- The reconfiguration of the vertically-integrated electric utility. Restructuring usually refers to separation of the various utility functions into individually-operated and -owned entities.
RETROFIT-- broad term that applies to any change after the original purchase, such as adding equipment not a part of the original purchase. As applied to alternative fuel vehicles, it refers to conversion devices or kits for conventional fuel vehicles. (Same as after-market)
RTG -- A Regional Transmission Group. A voluntary organization of transmission owners,users, and other entities interested in coordinating transmission planning, expansion, operation,and use on a regional and inter-regional basis. Such groups are subject to FERC approval.
- Anza Electric Cooperative in Anza
- Plumas-Sierra Rural Electric Cooperative in Portola
- Sunrise Valley Electrification Corporation in Alturas