The cover for the gear box, drive train, generator, and other components of a wind turbine.

Name Plate

A metal tag attached to a machine or appliance that contains information such as brand name, serial number, voltage, power ratings under specified conditions, and other manufacturer supplied data.

National Electrical Code (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. The intent of the NEC is to ensure safe electrical systems are designed and installed. The National Fire Protection Association has sponsored the NEC since 1911. The NEC changes as technology evolves and component sophistication increases. The NEC is updated every three years. Following the NEC is required in most locations.

National Rural Electric Cooperative Association (NRECA)

This is a national organization dedicated to representing the interests of cooperative electric power providers and the consumers they serve. Members come from the 46 states that have an electric distribution cooperative.

Natural Cooling

Space cooling achieved by shading, natural (unassisted, as opposed to forced) ventilation, conduction control, radiation, and evaporation; also called passive cooling.

Natural Draft

Draft that is caused by temperature differences in the air.

Natural Gas

A hydrocarbon gas obtained from underground sources, often in association with petroleum and coal deposits. It generally contains a high percentage of methane, varying amounts of ethane, and inert gases; used as a heating fuel.

Natural Gas Steam Reforming Production

A 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. The second step is to convert the carbon monoxide with steam to produce additional hydrogen and carbon dioxide.

Natural Ventilation

Ventilation that is created by the differences in the distribution of air pressures around a building. Air moves from areas of high pressure to areas of low pressure with gravity and wind pressure affecting the airflow. The placement and control of doors and windows alters natural ventilation patterns.

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 Generation

Equal to gross generation less electricity consumption of a power plant.

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. Equal to the higher heating value minus 1050W where W is the weight of the water formed from the hydrogen in the fuel, and 1050 is the latent heat of vaporization of water, in Btu, at 77 degrees Fahrenheit.

Net Metering

The 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 solar photovoltaic system). The net energy produced or consumed is purchased from or sold to the power provider, respectively.

Net Present Value

The value of a personal portfolio, product, or investment after depreciation and interest on debt capital are subtracted from operating income. It can also be thought of as the equivalent worth of all cash flows relative to a base point called the present.

Nitrogen Dioxide

This compound of nitrogen and oxygen is formed by the oxidation of nitric oxide (NO) which is produced by the combustion of solid fuels.

Nitrogen Oxides (NO
The products of all combustion processes formed by the combination of nitrogen and oxygen.

Nominal Capacity

The approximate energy producing capacity of a power plant, under specified conditions, usually during periods of highest load.

Nominal Price

The price paid for goods or services at the time of a transaction; a price that has not been adjusted to account for inflation.

Nocturnal Cooling

The effect of cooling by the radiation of heat from a building to the night sky.

Nonrenewable Fuels

Fuels that cannot be easily made or “renewed,” such as oil, natural gas, and coal.

Non-Utility Generator/Power Producer

A 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 the conduct of their industrial and commercial operations.

Normal Recovery Capacity

A characteristic applied to domestic water heaters that is the amount of gallons raised 100 degrees Fahrenheit per hour (or minute) under a specified thermal efficiency.

N-Type Semiconductor

A semiconductor produced by doping an intrinsic semiconductor with an electron-donor impurity (e.g., phosphorous in silicon).

Nuclear Energy

Energy that comes from splitting atoms of radioactive materials, such as uranium, and which produces radioactive wastes.