ENERGY Glossary
Letter L
LADWP - The acronym for Los Angeles Department of Water and Power
an electric, municipal utility serving the greater Los Angeles, California, region.
LANDFILL GAS - Gas generated by the natural
degrading and decomposition of municipal solid waste by anaerobic
microorganisms in sanitary landfills. The gases produced, carbon dioxide and
methane, can be collected by a series of low-level pressure wells and can be processed
into a medium Btu gas that can be burned to generate steam or electricity.
LASER - A very intense, uniform beam of electromagnetic radiation. Acronym for
Light Amplification by Simulated Emission of Radiation.
LATENT HEAT - A change in the heat content that
occurs without a corresponding change in temperature, usually accompanied by a
change of state (as from liquid to vapor during evaporation).
LATENT LOAD - The cooling load caused by
moisture in the air.
LATITUDE - The angular distance north or south of the
equator, measured in degrees of arc.
LAYOFF (Electric utility) - Excess capacity of a generating unit, available for a
limited time under the terms of a power sales agreement.
LAY UP - Lay up is another term for cold storage and
describes the status of equipment (such as a power plant) that has been placed in
storage ("mothballed") for latter use.
LEADED GASOLINE - Gasoline containing
tetraethyl lead, an important constituent in antiknock gasoline. Leaded gasoline is
no longer sold in the United States.
LOAD CENTERS - A geographical area where
large amounts of power are drawn by end-users.
LIFE-CYCLE COST - Amount of money necessary
to own, operate and maintain a building over its useful life.
LIFE EXTENSION - A term used to describe
capital expenses which reduce operating and maintenance costs associated with
continued operation of electric utility boilers. Such boilers usually have a 40 year
operating life under normal circumstances.
LIFELINE RATES - Rates charged by a utility company for the low income, the
disadvantaged and senior citizens. The rates provide a discount for minimum
necessary utilities, such as electricity requirements of typically 300 to 400
kilowatt/hours per month.
LIGHT WATER REACTOR (LWR) - A nuclear power unit that uses ordinary water
to cool its core. The LWR may be a boiling water reactor or a pressurized water
reactor.
LIGNITE - Brownish black coal having qualities in
between those of bituminous coal and peat. The texture of the original wood often is
visible in lignite.
LIQUEFACTION - The process of making synthetic liquid fuel from coal. The term
also is used to mean a method for making large amounts of gasoline and heating oil
from petroleum.
LIQUEFIED GASES - Gases that have been or can
be changed into liquid form. These include butane, butylene, ethane, ethylene,
propane and propylene.
LNG (LIQUEFIED
NATURAL GAS) - Natural gas that has been condensed to a liquid, typically by
cryogenically cooling the gas to minus 260 degrees Fahrenheit (below zero).
LPG (LIQUEFIED PETROLEUM GAS) - A mixture of gaseous hydrocarbons, mainly
propane and butane that change into liquid form under moderate pressure. LPG or
propane is commonly used as a fuel for rural homes for space and water heating, as
a fuel for barbecues and recreational vehicles, and as a transportation fuel. It is
normally created as a by-product of petroleum refining and from natural gas
production.
LIQUID BRINE - A type of geothermal energy
resource that depends on naturally occurring hot water solution found within the
earth. Technology for this novel energy source is being developed in the Salton Sea
area in Southern California.
LIQUID PETROLEUM GAS - See
LPG.
LOAD - The amount of electric power supplied to meet one
or more end user's needs.
LOAD - An end-use device or an end-use customer that
consumes power. Load should not be confused with demand, which is the measure of
power that a load receives or requires.
LOAD DIVERSITY - The condition that exists when the peak demands of a variety
of electric customers occur at different times. This is the objective of "load molding"
strategies, ultimately curbing the total capacity requirements of a utility.
LOAD FACTOR - A percent telling the difference
between the amount of electricity a consumer used during a given time span and
the amount that would have been used if the usage had stayed at the consumer's
highest demand level during the whole time. The term also is used to mean the
percentage of capacity of an energy facility - such as power plant or gas pipeline -
that is utilized in a given period of time.
LOADING FACTOR -- Ratio of actual electricity consumed and total
potential consumption. Used when analyzing electricity consumption in a
large population. A loading factor of 0.5 means that 50% of homes are
consuming all of the electricity they are able or that, on average, all
of the homes are only consuming 50% of the power they have the potential
to consume.
LOAD MANAGEMENT - Steps taken to reduce power demand at peak load times
or to shift some of it to off-peak times. This may be with reference to peak hours,
peak days or peak seasons. The main thing affecting electric peaks is air-conditioning
usage, which is therefore a prime target for load management efforts. Load
management may be pursued by persuading consumers to modify behavior or by
using equipment that regulates some electric consumption.
LOOP FLOW - The difference between scheduled and actual power flows on electric
transmission lines.
LOSSES (Electric utility) - Electric energy or capacity that is wasted in the normal
operation of a power system. Some kilowatt-hours are lost in the form of waste heat
in electrical apparatus such as substation conductors. LINE LOSSES are kilowatts or
kilowatt-hours lost in transmission and distribution lines under certain
conditions.
LOW-E - A special coating that reduces the emissivity of a window assembly,
thereby reducing the heat transfer through the assembly.
LOW EMISSION VEHICLE (LEV) - a vehicle certified by the
California Air Resources Board to have emissions from zero to
50,000 miles no higher than 0.075 grams/mile (g/mi) of
non-methane organic gases, 3.4 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.)
LOW-SULFUR COAL - Coal having one percent or less of sulfur by weight.
LOW-SULFUR OIL - Oil having one percent or less of sulfur by weight.
LUMEN - A measure of the amount of light available from a light source
equivalent to the light emitted by one candle.
LUMENS/WATT - A measure of the efficacy of a light fixture; the number of
lumens output per watt of power consumed.
LUMEN MAINTENANCE
CONTROL - An electrical control device designed to vary the electrical
consumption of a lighting system in order to maintain a specified illumination
level.
LUMINAIRE - A complete lighting unit consisting of a lamp or lamps together
with the parts designed to distribute the light, to position and protect the lamps and
to connect the lamps to the power supply. California Code of Regulations, Section 2-
1602(h)].
LUX - A unit of illumination equal to the direct illumination
on a surface that is everywhere one meter from a uniform point source of one
candle; a unit of illumination that is equal to one lumen per square meter. Also see
footcandle.
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Page Updated: February 10, 2003