UDC -- Utility distribution company. An entity that owns a distribution system for the delivery of energy to and from the ISO-controlled grid, and that provides regulated, retail service to eligible end-use customers who are not yet eligible for direct access, or who choose not to arrange services through another retailer.
UNCONDITIONED SPACE -- A space that is neither directly nor indirectly conditioned space, which can be isolated from conditioned space by partitions and/or closeable doors. [See California Code of Regulations, Title 24, Section 2-5302]
ULEV (ULTRA-LOW EMISSION VEHICLE) Ð- a vehicle certified by the California Air Resources Board to have emissions from zero to 50,000 miles no higher than 0.040 grams/mile (g/mi) of non-methane organic gases, 1.7 g/mi of carbon monoxide, and 0.2 g/mi of nitrogen oxides. Emissions from 50,000 to 100,000 miles may be slightly higher (See chart in Chapter 2.)
ULTRAHIGH VOLTAGE TRANSMISSION -- Transporting electricity over bulk-power lines at voltages greater than 800 kilovolts.
UNBUNDLING -- Disaggregating electric utility service into its basic components and offering each component separately for sale with separate rates for each component. For example, generation, transmission and distribution could be unbundled and offered as discrete services.
UNIVERSAL SERVICE -- Electric service sufficient for basic needs (an evolving bundle of basic services) available to virtually all members of the population regardless of income.
UNLEADED GASOLINE -- Gasoline that has had tetraethyl lead removed in conformance with federal and state regulations.
UPGRADE (Electric utility) -- Replacement or addition of electrical equipment resulting in increased generation or transmission capability.
UPRATE (Electric utility) -- An increase in the rating or stated measure of generation or transfer capability.
UPSTREAM -- A term used in the petroleum industry referring to the exploration and production side of the business. This includes pipelines but production before reaching the refinery.
URANIUM -- A radioactive element, found in ores, of which atoms can be split to create energy.
URANIUM ENRICHMENT -- The process of increasing the percentage of pure uranium above the levels found in naturally occurring uranium ore, so that it may be used as fuel.
UTILITY -- A regulated entity which exhibits the characteristics of a natural monopoly. For the purposes of electric industry restructuring, "utility" refers to the regulated, vertically-integrated electric company. "Transmission utility" refers to the regulated owner/operator of the transmission system only. "Distribution utility" refers to the regulated owner/operator of the distribution system which serves retail customers.
U-value or U-factor -- A measure of how well heat is transferred by the entire window - the frame, sash and glass - either into or out of the building. U-value is the opposite of R-value. The lower the U-factor number, the better the window will keep heat inside a home on a cold day.
VAV System (Variable Air Volume System) -- A mechanical HVAC system capable of serving multiple zones which controls the temperature maintained in a zone by controlling the amount of heated or cooled air supplied to the zone.VAPOR BARRIER -- A material with a permeance of one perm or less which provides resistance to the transmission of water vapor. [See California Code of Regulations, Title 24, Section 2-5302]
VENTILATION -- The process of supplying or removing air by natural or mechanical means to or from any space. Such air may or may not have been conditioned or treated.
VERIFICATION PHASE -- The step of the California Energy Contingency Plan to determine the existence and scope of an energy shortage and report to Energy Commission executives, the Governor and the Legislature where required under the plan.
VERTICAL INTEGRATION -- An arrangement whereby the same company owns all the different aspects of making, selling, and delivering a product or service. In the electric industry, it refers to the historically common arrangement whereby a utility would own its own generating plants,transmission system, and distribution lines to provide all aspects of electric service.
VISIBLE LIGHT TRANSMITTANCE -- The ratio of visible light transmitted through a substance to the total visible light incident on its surface.
VOLT -- A unit of electromotive force. It is the amount of force required to drive a steady current of one ampere through a resistance of one ohm. Electrical systems of most homes and office have 120 volts.
- VOLTAGE OF A CIRCUIT (Electric utility) -- The electric pressure of a circuit, measured in volts. Usually a nominal rating, based on the maximum normal effective difference of potential between any two conductors of the circuit.
VOLUMETRIC WIRES CHARGE -- A type of charge for using the transmission and/or distribution system that is based on the volume of electricity that is transmitted.