MTBEMethyl Tertiary Butyl Ether (MTBE) is an ether compound used as a gasoline blending component to raise the oxygen content of gasoline.
MTC (Massachusetts Technology Collaborative)MTC is the state's quasi-public development agency for renewable energy and the innovation economy, which is responsible for one-quarter of all jobs in…
Multi-Zone SystemA building heating, ventilation, and/or air conditioning system that distributes conditioned air to individual zones or rooms.
Multijunction DeviceA high-efficiency photovoltaic device containing two or more cell junctions, each of which is optimized for a particular part of the solar spectrum.
Multijunction solar cellA photovoltaic device comprised of two or more semiconductor materials or cell junctions, each capable of producing electricity with the photovoltaic…
Multiple useA combination of balanced and diverse resource uses that takes into account the long-term needs of future generations for renewable and nonrenewable…
Multiple Use ClassesClass C is for lands designated either as wilderness or for wilderness study areas. These lands are managed to protect their wilderness values.
Multiple use managementCoordinated management of the various surface and subsurface resources, without permanent impairment of the productivity of the land, that will best meet…
municipal solid wasteAny organic matter, including sewage, industrial, and commercial wastes, from municipal waste collection systems.
Municipal Solid Waste (MSW)(MSW)Waste material from households and businesses in a community that is not regulated as hazardous.
Municipal WasteAs 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…
NacelleThe cover for the gear box, drive train, generator, and other components of a wind turbine.
Name PlateA metal tag attached to a machine or appliance that contains information such as brand name, serial number, voltage, power ratings under specified…
Nameplate ratingThe maximum power-generating capacity of a generator or power-generating facility.
National balancing point (NBP)(NBP)Location of wholesale natural gas trading in the United Kingdom; a key reference point for spot and forward market natural gas transactions in Europe.
National Electrical Code (NEC)(NEC)The NEC is a set of regulations that have contributed to making the electrical systems in the United States one of the safest in the world.
National Environmental Policy Act (NEPA)(NEPA)A comprehensive federal law requiring analysis of the environmental impacts of federal actions such as the approval of grants; also requiring preparation…
National Environmental Policy Act of 1969 (NEPA)(NEPA)Requires federal agencies to prepare a detailed statement on the environmental impacts of their proposed major actions that are significantly affecting…
National Forest Management Act (NFMA)(NFMA)A federal law passed in 1976 as an amendment to the Forest and Rangeland Renewable Resources Planning Act requiring the preparation of Regional Guides and…
National Historic Preservation Act (NHPA)(NHPA)A federal law providing that property resources with significant national historic value be placed on the National Register of Historic Places.
National Historic TrailsThese trails are designated by Congress under the National Trails System Act of 1968 and follow, as closely as possible, on federal land, the original…
National Landscape Conservation System (NLCS)(NLCS)Created by the BLM in June 2000 to increase public awareness of BLM lands with scientific, cultural, educational, ecological, and other values.
National Recreation AreaAn area designated by Congress to assure the conservation and protection of natural, scenic, historic, pastoral, fish, and wildlife values, and to provide…
National Register of Historic Places (NRHP)(NRHP)A comprehensive list of districts, sites, buildings, structures, and objects that are significant in American history, architecture, archaeology…
Native AmericanOf, or relating to, a tribe, people, or culture that is indigenous to the United States. (See Native American Graves Protection and Repatriation Act)
native ligninThe lignin as it exists in the lignocellulosic complex before separation.
Native loadWholesale and retail customers that the electric transmission provider is obligated to serve.
Natural CoolingSpace cooling achieved by shading, natural (unassisted, as opposed to forced) ventilation, conduction control, radiation, and evaporation; also called…
Natural DraftDraft that is caused by temperature differences in the air.
Natural drainagesNatural systems that convey water (such as a stream channel) that may be perennial, intermittent, or ephemeral.
Natural gasA hydrocarbon gas obtained from underground sources, often in association with petroleum and coal deposits.
Natural Gas Steam Reforming ProductionA two step process where in the first step natural gas is exposed to a high-temperature steam to produce hydrogen, carbon monoxide, and carbon dioxide.
Natural VentilationVentilation that is created by the differences in the distribution of air pressures around a building.
NatureServeA nonprofit organization that provides the scientific information and tools needed to guide effective conservation action.
NatureServe ExplorerA Web site from NatureServe that provides authoritative conservation information in a searchable database for more than 70,000 plants, animals, and…
Neat fuelFuel that is free from admixture or dilution with other fuels.
Negative Energy BalanceWhen producing a fuel takes more energy than the amount of energy the fuel provides.
Neo-Traditional DevelopmentA traditional neighborhood, where a mix of different types of residential and commercial developments form a tightly knit unit.
Neotropical migrantsBirds (especially songbirds) that summer in North America but migrate to the tropics for the winter.
Net (Lower) Heating Value (NHV)The potential energy available in a fuel as received, taking into account the energy loss in evaporating and superheating the water in the fuel.
Net billingThe arrangement by which the Bonneville Power Administration financed the cost of nuclear power plants.
Net emissionsApplied to greenhouse gas emissions inventory in this report. "Net emissions" means gross emissions (including all industrial activities, mostly fossil…
Net Energy Production (or Balance)The amount of useful energy produced by a system less the amount of energy required to produce the fuel.
Net GenerationEqual to gross generation less electricity consumption of a power plant.
Net heating value (NHV)(NHV)The potential energy available in the fuel as received, taking into account the energy loss in evaporating and superheating the water in the sample.
Net MeteringThe practice of using a single meter to measure consumption and generation of electricity by a small generation facility (such as a house with a wind or…
Net Present ValueThe value of a personal portfolio, product, or investment after depreciation and interest on debt capital are subtracted from operating income.
neutral detergent fiberOrganic matter that is not solubilized after one hour of refluxing in a neutral detergent consisting of sodium lauryl sulfate and EDTA at pH 7.
New UrbanismNeighborhood design trend used to promote community and livability. Characteristics include narrow streets, wide sidewalks, porches, and homes located…
New York Mercantile Exchange (Nymex)The centralized exchange where CFTC–sanctioned natural gas and electricity futures are traded in the United States.
Night-sky impactAn interference with enjoyment of dark night skies resulting from light pollution.
Nighttime mean rural background levelNighttime (10 p.m. to 7 a.m.) average sound level in the rural environment, from all sources, rather than a particular noise that is of interest.
Nitrogen DioxideThis compound of nitrogen and oxygen is formed by the oxidation of nitric oxide (NO) which is produced by the combustion of solid fuels.
Nitrogen dioxide (NO<sub>2</sub>)(NO2)A toxic, reddish-brown gas that is a strong oxidizing agent, produced by combustion (as of fossil fuels).
Nitrogen fixationThe conversion of atmospheric nitrogen to biologically usable nitrates.
Nitrogen oxide (NOx)(NOx)NOx is a key pollutant in the formation of acid rain and ground-level ozone (smog).
nitrogen oxides(NOx) A product of photochemical reactions of nitric oxide in ambient air, and the major component of photochemical smog.
Nitrogen Oxides (NOx)(NOx)The products of all combustion processes formed by the combination of nitrogen and oxygen.
Nocturnal CoolingThe effect of cooling by the radiation of heat from a building to the night sky.
NoiseAny unwanted sound that interferes with speech and hearing, causes damage to hearing, or annoys a person.
Noise criteriaQuantitative noise limits, below which it is acceptable for people to hear. Typically, noise criteria are specified in ordinances, regulations, or…
Nominal CapacityThe approximate energy producing capacity of a power plant, under specified conditions, usually during periods of highest load.
Nominal PriceThe price paid for goods or services at the time of a transaction; a price that has not been adjusted to account for inflation.
Non-point source pollutionPollution whose source is not specific in location; the sources of the pollutant discharge are dispersed, not well defined or constant.
Non-Point Source Pollution (NPS)(NPS)Pollution that cannot be identified as coming from a specific source and thus cannot be controlled through the issuing of permits.
non-renewable resourceA non-renewable energy resource is one that cannot be replaced as it is used. Although fossil fuels, like coal and oil, are in fact fossilized biomass…
Non-Utility Generator/Power ProducerA class of power generator that is not a regulated power provider and that has generating plants for the purpose of supplying electric power required in…
Nonattainment AreaThe EPA's designation for an air quality control region (or portion thereof) in which ambient air concentrations of one or more criteria pollutants exceed…
Nonattainment area (NAA)(NAA)A geographic area in which air quality is worse than that allowed by federal air pollution standards.
Noncommercial speciesTree species that do not normally develop into suitable trees for conventional forest products because of small size, poor form, or inferior quality.
Nongame speciesThose species not commonly harvested either for sport or profit.
Nonmarket valueMost environmental goods and services, such as clean air and water, and healthy fish and wildlife populations, are not traded in markets, meaning that…
Nonpoint light sourceA light source that is sufficiently large in size and close enough to the viewer to appear as an illuminated surface rather than a star-like point of…
Nonpoint sourcesDiffuse pollution sources (i.e., without a single point of origin or not introduced into a receiving stream from a specific outlet).
Nonrenewable FuelsFuels that cannot be easily made or "renewed," such as oil, natural gas, and coal.
Nonroad mobile sources (emissions)Sources such as farm and construction equipment, gasoline-powered lawn and garden equipment, and power boats and outdoor motors that emit pollutants.
Normal Recovery CapacityA characteristic applied to domestic water heaters that is the amount of gallons raised 100 degrees Fahrenheit per hour (or minute) under a specified…
North American Electric Reliability Council (NERC)(NERC)A council formed in 1968 by the electric utility industry to promote the reliability and adequacy of bulk power supply in the electric utility systems of…
NOx Budget Trading Program (NBP)(NBP)An ozone season cap-and-trade program intended to help states meet their NOx state implementation plan (SIP) required reductions.
NOx State Implementation Plan (SIP)(SIP)Building upon analyses done by the Ozone Transport Assessment Group (OTAG), this rule was finalized by the Environmental Protection Agency (EPA) in 1998.