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Marginal Cost: The cost of producing one additional unit of a particular product or service.

Market-Based Pricing: Electric service prices determined in an open market system of supply and demand under which the price is set solely by agreement as to what a buyer will pay and a seller will accept. Such prices could recover less or more than full costs, depending upon what the buyer and seller see as their relevant opportunities and risks.

Master-metered: The system by which multi-unit buildings or mobile home parks are connected to a single meter.  The master-meter holder receives a single bill from the utility and collects from tenants individually.  The utility has no liability for repairs or maintenance beyond the master meter.

MAS – Multiple Address System:  A communications system serving a minimum of four remote stations.

Maximum Rates: The ceiling set by the Commission on what household goods moving and storage companies can charge.  Such carriers may charge no more than these rates but may reduce their rates to respond to competition.

MB – Megabyte or Meg.: A measure of storage capacity equal to about one million bytes or about 500 typed pages.

Mbps – Megabits per second:  1,000,000 bits per second. A measure of how fast data can be transmitted.

Mbps: megabytes per second.

MCF: One thousand cubic feet

MCP – Market Clearing Price:  The price at which supply equals demand for the Day Ahead and/or Hour Ahead Markets.

Measured Telephone Rates: A telephone rate plan by which customers pay for the number of calls and the duration of each call.  In California , most businesses are already on such a plan and, in most areas, residential customers may choose the service.

Measured Telephone Service: An accounting procedure which allows a utility to record expenses and/or revenues off-book for a set period of time during which, because of such changes as fuel cost increases, those expenses or costs differ from its projected figures for that period of time; the utility's accounts may be balanced, that is, increased or decreased, in its next formal rate increase or other proceeding.

Memory: The part of a computer where information is stored.

Menu: A list of options (e.g., EDIT, PRINT) in computer processing displayed on a video screen, with selection made on a keyboard or by pointing a special device (the mouse) at the item listed on the screen.

Mercalli: A standard scale of relative measurement of earthquake intensity.

Meter Retrofit Programs: Programs targeted toward un-metered homes and businesses that either install a new meter or repair an existing meter to provide for billing based on volume of use.

Mhz: megahertz.

MHP: Mobile Home Park .


Minimum Rates: Covering highway carriers, these charges are the minimum set by the Commission that a carrier can charge for transporting materials and are published in minimum rate tariffs (MRTs).  It is unlawful to charge below these rates, unless the Commission approves a deviation.

MMBtu: Million British Thermal Units (equals on Dth).

MMcf/d: Million cubic feet per day (also MMCfd).

MMth: Million therms.

Modem –Modular-Demodulator: Hardware that allows a computer to communicate with other computers through ordinary telephone lines (if they also have modems attached).

MOD-POD – Modified Presiding Officer's Decision: Issued by PUC Administrative Law Judges (ALJ).  In certain proceeding the ALJ issues a ruling called a POD.  If that decision is modified, it becomes a MOD-POD.

Monitor: Computer Screen

Motor Transportation Broker: Any person or corporation arranging or offering to arrange for compensation for the hauling of property by any motor carrier over California highways.

MOU - Memoranda of Understanding: A formalized, legal understanding between parties to enter into an agreement or create stipulations in proceedings or cases.

Mountain Front Recharge: Natural recharge that occurs at the base of the mountains because of rainfall or snow melt at higher elevations.

Mouse: A peripheral device that is connected to a computer allowing the operator to move around the screen without the aid of the keyboard.

MSA – Metropolitan Statistical Area:  The MSA is comprised of one of more counties and of a high degree of social and economic integration as defined by the U.S. Census Bureau.

MSO – Multiple System Operator:  A company that operates more than one cable TV system.

MUD – Multi-User Dimension:  This term refers to users who connect to each other via a host computer.

MUNI – Municipally-Owned Utility:  A utility owned and operated by a city or county.  The PUC does not have regulatory authority over munis.

Municipal Water Use: All non-irrigation uses of water supplied by a city, town, private water company or irrigation district.

MW – Megawatt: One million watts or 1,000 kW.

MWh: Megawatt-hours.


NANPA – North American Numbering Plan Administrator: An integrated telephone numbering plan serving 19 North American countries that share its resources. On the Internet at

NARUC – National Association of Regulatory Utility Commissioners: A non-profit organization founded in 1889. Its members include the governmental agencies that are engaged in the regulation of utilities and carriers in the fifty States, the District of Columbia , Puerto Rico and the Virgin Islands . NARUC's member agencies regulate the activities of telecommunications, energy, and water utilities. On the Internet at

Natural Gas: A naturally occurring mixture of hydrocarbon and nonhydrocarbon gases found in porous geological formations beneath the earth's surface, often in association with petroleum. The principal constituent is methane.

Natural Recharge: The natural replenishment of an aquifer.

NDIEC – Non-dominant Interexchange Carrier: Telephone companies, excluding AT&T, which provide long distance service interstate or between LATAs within a state.

NEI – Nuclear Energy Institute: Policy organization of the nuclear energy and technologies industry and participates in both the national and global policy-making process. NEI's objective is to ensure the formation of policies that promote the beneficial uses of nuclear energy and technologies in the U.S. and around the world.  On the Internet at

NENA – National Emergency Number Association: NENA's mission is to foster the technological advancement, availability, and implementation of a universal emergency telephone number system. In carrying out its mission, NENA promotes research, planning, training and education. The protection of human life, the preservation of property and the maintenance of general community security are among NENA's objectives. On the Internet at

Net Capability: The maximum load-carrying ability of the equipment, exclusive of station use, under specified conditions for a given time interval, independent of the characteristics of the load. Capability is determined by design characteristics, physical conditions, adequacy of prime mover, energy supply, and operating limitations such as cooling and circulating water supply and temperature, headwater and tailwater elevations, and electrical use.

Net Generation: Gross generation minus the electric energy consumed at the generating station for station use.

Net Operating Income: The amount of revenue from utility operations remaining after operation and maintenance expenses, depreciation expenses, and taxes are deducted.  The revenues and expenses that produce net operating income are commonly referred to as "above-the-line" items.

NF – Nanofiltration: A form of filtration using membranes with larger pores than reverse osmosis.

NFCA – Noncore Fixed Cost Account:  A balancing account that matches the authorized base revenue requirement and certain other costs for noncore customers with recorded revenues intended to recover that revenue requirement and the other specified costs.  The balances in the NFCA have been recoverable through rates in varying degrees over time, as determined by the PUC.

NGA – Natural Gas Act:  Federal legislation enacted in 1938 that established regulatory control over companies engaged in the interstate sale and transmission of natural gas.

NGV – Natural Gas Vehicle:  A vehicle that uses conventional combustion engines modified to run on natural gas.

NII – National Information Infrastructure:  Refers to a nationwide network of integrated telecommunications that connects people, businesses, schools, institutions and governments with one another.

NOI – Notice of Inquiry:  A Notice of Inquiry is adopted by the Federal Communications Commission (FCC) Commissioners for fact gathering purposes; and as a method for seeking public comments.  Or, Notice of Intent: Preliminary data filed with the PUC by a utility in preparation for the formal filing of a general rate increase application.

NOPR – Notice of Proposed Rulemaking:  A Notice of Proposed Rulemaking is adopted by the Federal Communications Commission (FCC) Commissioners to detail proposed changes to FCC rules and to seek public comment on these proposals.

NP - Number Porting:  Number porting allows customers to switch between telephone service providers while retaining their original telephone number.  Also called Local Number Portability (LNP).

NPA – Numbering Plan Area:  A geographical area in which no two telephones have the same seven-digit number.

NPTOR – Net-Plant Turnover Ratio: Gross operating revenue divided by net-plant.  Net plant is total utility plant less accumulated depreciation reserve.

NPV – Net Present Value: Form of calculating discounted cash flow. It encompasses the process of calculating the discount of a series of amounts of cash at future dates, and summing them.

NRC – Nuclear Regulatory Commission: An independent agency established by the Energy Reorganization Act of 1974 to regulate civilian use of nuclear materials. The NRC is headed by a five-member Commission.  On the Internet at

NRDC – National Resources Defense Council: An environmental action organization.  On the Internet at

NRF – New Regulatory Framework: Adopted in 1989, the New Regulatory Framework (NRF) is the PUC's designation for a price cap form of regulation used to regulate California 's four largest ILECs (SBC, Verizon California, Roseville Telephone Company, Citizens Telephone Company of California ).  Previously, these ILECs were regulated under traditional cost of service rate of return regulation, which required substantial PUC oversight. The NRF relies on a profit to motivate utilities to operate in the most efficient way possible in order to maximize revenues.  Under price caps, the prices of utility services are declined from costs.  The utility is allowed to earn a higher rate of return than under rate of return regulation to provide the profit incentive.

NTSB – National Transportation Safety Board: An independent Federal agency charged by Congress with investigating every civil aviation accident in the U.S. and significant accidents in the other modes of transportation -- railroad, highway, marine and pipeline -- and issuing safety recommendations aimed at preventing future accidents.  On the Internet at

Nuclear Fuel: Fissionable materials that have been enriched to such a composition that, when placed in a nuclear reactor, will support a self-sustaining fission chain reaction, producing heat in a controlled manner for process use.

Nuclear Power Plant: A facility in which heat produced in a reactor by the fissioning of nuclear fuel is used to drive a steam turbine.

NVWT – Napa Valley Wine Train: A year-round gourmet-dining excursion through Napa Valley for brunch, lunch or dinner.

NXX: Term refers to the three-digit central office prefix assigned to a seven-digit telephone number; an acronym for North American Direct Distance Dialing Numbering Plan.


Last Modified: 1/28/2008

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