Glossary of Terms - M

• Major - A term broadly applied to those multinational oil companies which by virtue of size, age, or degree of integration are among the preeminent companies in the international petroleum industry.
• Majority Carrier - Current carriers (either free electrons or holes) that are in excess in a specific layer of a semiconductor material (electrons in the n-layer, holes in the p-layer) of a cell.
• Manual J - The standard method for calculating residential cooling loads developed by the Air-Conditioning and Refrigeration Institute (ARI) and the Air Conditioning Contractors of America (ACCA) based largely on the American Society of Heating, Refrigeration, and Air-Conditioning Engineer's (ASHRAE) "Handbook of Fundamentals."
• Margin - The amount of money or collateral deposited by a customer with his broker, or deposited by a broker with a clearing member, or by a clearing member with the clearinghouse, for the purpose of insuring the broker or clearinghouse against adverse price movement on open futures contracts. The margin is not partial payment on a purchase. 1) Initial margin is the minimum deposit per contract required by the broker when a futures position is opened. 2) Maintenance margin is a sum which must be maintained on deposit at all times. If the equity in a customers' account drops to, or under, that level because of an adverse price movement, the broker must issue a margin call to restore the customers' equity. Margins are set by the Exchange based on its analysis of price risk volatility in the market at that time. See variation margin.
• Margin Call - A demand for additional margin funds when futures prices move adverse to a trader's position, or if margin requirements are increased. Buyers of options are not subject to margin calls.
• Marginal Cost - The sum that has to be paid the next increment of product of service. The marginal cost of electricity is the price to be paid for kilowatt-hours above and beyond those supplied by presently available generating capacity.
• Marked-to-Market - Daily cash flow system used by U.S. futures exchanges to maintain a minimum level of margin equity for a given futures or options contract position by calculating the gain or loss in each contract position resulting from changes in the price of the futures or options contracts at the end of each trading day.
• Market Correction - In technical analysis, a small reversal in prices following a significant trending period.
• Market Eligibility - The percentage of equipment still available for retrofit to the demand-side management measure. For example, if 20 percent of customers where demand controllers are feasible have already purchased demand controllers, then the eligible market eligibility factor is 80 percent.
• Market Maker - An independent trader or trading firm which is prepared to buy and sell futures or options contracts in a designated market. Market makers provide a two-sided (bid and ask) market and greater liquidity.
• Market Order - An order to be filled immediately at the current market price.
• Market-Based-Price - A price set by the mutual decisions of many buyers and sellers in a competitive market.
• Marketer - An agent for generation projects who markets power on behalf of the generator. The marketer may also arrange transmission, firming or other ancillary services as needed. Though a marketer may perform many of the same functions as a broker, the difference is that a marketer represents the generator while a broker acts as a middleman.
• Market-if-Touched Order - An order that becomes a market order when a particular price is reached. A sell MIT is placed above the market; a buy MIT is placed below the market.
• Marketing Cost - Expenses directly associated with the preparation and implementation of the strategies designed to encourage participation in a DSM program. The category excludes general market and load research costs.
• Market-on-Close - An order to buy or sell at the end of the trading session at a price within the closing range of prices.
• Mass Burn Facility - A type of municipal solid waste (MSW) incineration facility in which MSW is burned with only minor presorting to remove oversize, hazardous, or explosive materials. Mass burn facilities can be large, with capacities of 3000 tons (2.7 million kg) of MSW per day or more. They can be scaled down to handle the waste from smaller communities, and modular plants with capacities as low as 25 tons (22.7 thousand kg) per day have been built. Mass burn technologies represent over 75% of all the MSW-to-energy facilities constructed in the United States to date. The major components of a mass burn facility include refuse receiving and handling, combustion and steam generation, flue gas cleaning, power generation (optional), condenser cooling water, residue ash hauling and landfilling.
• Maximum Demand - Highest demand of the load occurring within a specified period of time.
• Maximum Price Fluctuation - A commodity exchange's established maximum limits for fluctuations in futures prices during any one trading session.
• MCF - An abbreviation for one thousand cubic feet of natural gas with a heat content of 1,000,000 Btus, or 10 therms.
• Mean Power Output (of a Wind Turbine) - The average power output of a wind energy conversion system at a given mean wind speed based on a Raleigh frequency distribution.
• Mean Wind Speed - The arithmetic wind speed over a specified time period and height above the ground (the majority of U.S. National Weather Service anemometers are at 20 feet (6.1 meters).
• Measure Life - The length of time that the demand-side management technology will last before requiring replacement. The measure life equals the technology life. These terms are used synonymously.
• Median Wind Speed - The wind speed with 50 percent probability of occurring.
• Medium Btu Gas - Fuel gas with a heating value of between 200 and 300 Btu per cubic foot.
• Medium Pressure - For valves and fittings, implies that they are suitable for working pressures between 125 to 175 pounds per square inch.
• Megawatt (MW) - One thousand kilowatts, or 1 million watts; standard measure of electric power plant generating capacity.
• Megawatt Hour (Mwh) - Amount of electricity needed to light ten thousand 100-watt light bulbs for a one-hour period. One million watts used for one hour.
• Member System - An eligible customer operating as part of an agency composed exclusively of other eligible customers.
• Met - An approximate unit of heat produced by a resting person, equal to about 18.5 Btu per square foot per hour.
• Meter Constant - This represents the ratio between instrument transformers (CTs, PTs) and the meter. It is used as a multiplier of the difference between meter readings to determine the kWh used. The meter constant is also used as a multiplier of the demand reading to determine the actual demand.
• Methane - A colorless, odorless, tasteless gas composed of one molecule of Carbon and four of hydrogen, which is highly flammable. It is the main constituent of "natural gas" that is formed naturally by methanogenic, anaerobic bacteria or can be manufactured, and which is used as a fuel and for manufacturing chemicals.
• Methanol (CH3OH; Methyl alcohol or wood alcohol) - A clear, colorless, very mobile liquid that is flammable and poisonous; used as a fuel and fuel additive, and to produce chemicals.
• Metric Ton (Tonne) - A unit of mass equal to 1,000 kilograms or 2,204.6 pounds.
• Microclimate - The local climate of specific place or habitat, as influenced by landscape features.
• Microgroove - A small groove scribed into the surface of a solar photovoltaic cell which is filled with metal for contacts.
• Micrometer - One millionth of a meter (10-6 m).
• Mid-America Interconnected Network (MAIN) -One of the ten regional reliability councils that make up the North American Electric Reliability Council (NERC).
• Mid-Atlantic Area Council (MACC) - One of the ten regional reliability councils that make up the North American Electric Reliability Council (NERC).
• Mid-Continent Area Power Pool (MAPP) - One of the ten regional reliability councils that make up the North American Electric Reliability Council (NERC).
• Middle Distillate - Hydrocarbons that are in the so-called "middle boiling range" of refinery distillation. Examples are heating oil, diesel fuels, and kerosene.
• Mill - A common utility monetary measure equal to one-thousandth of a dollar or a tenth of a cent.
• Minimum Price Fluctuation - Minimum unit by which a futures price or an options premium can fluctuate per trade, also known as tick size.
• Minority Carrier - A current carrier, either an electron or a hole, that is in the minority in a specific layer of a semiconductor material; the diffusion of minority carriers under the action of the cell junction voltage is the current in a photovoltaic device.
• Minority Carrier Lifetime - The average time a minority carrier exists before recombination.
• Mixing Valve - A valve operated by a thermostat that can be installed in solar water heating systems to mix cold water with water from the collector loop to maintain a safe water temperature.
• MMBtu - One million British thermal units, one dekatherm. Approximately equal to a thousand cubic feet (Mcf) of natural gas.
• MMcf - One million cubic feet.
• Mobile Substation - This is a movable substation which is used when a substation is not working or additional power is needed.
• Modified Degree-Day Method - A method used to estimate building heating loads by assuming that heat loss and gain is proportional to the equivalent heat-loss coefficient for the building envelope.
• Module - The smallest self-contained, environmentally protected structure housing interconnected photovoltaic cells and providing a single dc electrical output; also called a panel.
• Mogas - Industry slang for motor gasoline.
• Moisture Content - The water content of a substance (a solid fuel) as measured under specified conditions being the: Dry Basis, which equals the weight of the wet sample minus the weight of a (bone) dry sample divided by the weight of the dry sample times 100 (to get percent); Wet Basis, which is equal to the weight of the wet sample minus the weight of the dry sample divided by the weight of the wet sample times 100.
• Moisture Control - The process of controlling indoor moisture levels and condensation.
• Monitoring & Evaluation Cost - Expenditures associated with the planning, collection, and analysis of data used to assess program operation and effects. It includes activities such as load metering, customer surveys, new technology testing, and program evaluations that are intended to establish or improve the ability to monitor and evaluate the impacts of DSM programs, collectively or individually.
• Monoculture - The planting, cultivation, and harvesting of a single species of crop in a specified area.
• Monopoly - The only seller with control over market sales.
• Monopsony - The only buyer with control over market purchases.
• Motor - A machine supplied with external energy that is converted into force and/or motion.
• Motor Gasoline - A complex mixture of relatively volatile hydrocarbons, with or without small quantities of additives, which have been blended to form a fuel suitable for use in spark-ignition engines.
• Motor Oil - Refined lubricating oil, usually containing additives, used in internal combustion engines.
• Motor Speed - The number of revolutions that the motor turns in a given time period (i.e. revolutions per minute, rpm).
• Movable Insulation - A device that reduces heat loss at night and during cloudy periods and heat gain during the day in warm weather. A movable insulator could be an insulative shade, shutter panel, or curtain.
• MTBE - Methyl Tertiary Butyl Ether (MTBE) is an ether compound used as a gasoline blending component to raise the oxygen content of gasoline. MTBE is made by combining isobutylene (from various refining and chemical processes) and methanol (usually made from natural gas).
• Multicrystalline - Material that is solidified at such as rate that many small crystals (crystallites) form. The atoms within a single crystallite are symmetrically arranged, whereas crystallites are jumbled together. These numerous grain boundaries reduce the device efficiency. A material composed of variously oriented, small individual crystals. (Sometimes referred to as polycrystalline or semicrystalline).
• Multijunction Device - A high-efficiency photovoltaic device containing two or more cell junctions, each of which is optimized for a particular part of the solar spectrum.
• Multi-Zone System - A building heating, ventilation, and/or air conditioning system that distributes conditioned air to individual zones or rooms.
• Municipal Electric Utility - A power utility system owned and operated by a local jurisdiction. Municipality.
• Municipal Solid Waste (MSW) - Waste material from households and businesses in a community that is not regulated as hazardous.
• Municipal Waste - As defined in the Energy Security Act (P.L. 96-294; 1980) as "any organic matter, including sewage, sewage sludge, and industrial or commercial waste, and mixtures of such matter and inorganic refuse from any publicly or privately operated municipal waste collection or similar disposal system, or from similar waste flows (other than such flows which constitute agricultural wastes or residues, or wood wastes or residues from wood harvesting activities or production of forest products)."
• Municipal Waste to Energy Project (or Plant) - A facility that produces fuel or energy from municipal solid waste.
• Municipalization - The process by which a municipal entity assumes responsibility for supplying utility service to its constituents. In supplying electricity, the municipality may generate and distribute the power or purchase wholesale power from other generators and distribute it.
• MV - Medium volatile bituminous coal