Generally vertical access road, which gives access to the different floors of a mine. The extraction wells generally carry out the following functions: - Extraction, transport of materials, movement of persons (by means of cages moved by the extraction machine); - Primary ventilation (fresh air intake) from the mine ossatura; At the very least, another well (ventilation well) is required to evacuate the stale air; -Evacuation of water from underground aquifers (sewage); -Eventually descent from landfills.

Fluid obtained when partially or totally ionizing a gas at very high temperatures. The plasma used in nuclear fusion generally contains positive ions and electrons in substantially the same concentration. Thus, in large volumes, the plasma is electrically neutral and is a good conductor of electricity. For the heating of the plasma different systems can be used such as: - the ohmic heating;
- heating by injection of neutral atoms;
- radio frequency heating (cyclotron ion resonance, cyclotron resonance of electrons, lower hybrid heating);
- adiabatic compression heating;
- shock wave heating;
- heating by turbulence;
- laser heating.

Relation of the external pressure exerted by the plasma and the internal pressure that the field of magnetic confinement is able to exert. Is the equivalent of the relation between the energy density of a particle and the energy density of the magnetic field.

A condition in which the melt power produced in the plasma is greater than the power required to maintain the plasma temperature. In the case of tritium plasmas heated by deuterium jets, the criticality conditions are less severe, in view of Lawson's criterion for thermal plasmas (see Lawson's criterion).

Ions in a Plasma-Fusion, which belong to different elements from the fuel of the fusion reaction.

A macroscopic phenomenon of toroidal confinement plasmas in which large amounts of energy and numerous particles can be lost. They are initiated by nonlinear magnetohydrodynamic instabilities.

Coal with a higher content of poor quality products than quality coal.

Reserves whose volume or mass is indicated within a margin of error between plus or minus 30% and plus or minus 50%, according to a degree of exploitation with a forecast security of 90%. The upper limit of the error must be indicated.

At a given date, estimated quantities that the analysis of geological and technical data indicate as susceptible of being recovered from already discovered deposits with a moderate degree of probability suggesting the possibility of their existence but not sufficient to classify them As probable.
Due to the impossibility of predicting when and to what extent the recovery of such reserves will be possible in the future, the assessments must correspond to a set of values, but may be given by a single intermediate value that considers all uncertainties.

Electrical power of the plant or auxiliary services of a plant, plus losses in the plant transformers (in the main transformers).

Power that can be made available with a predetermined reliability.

Power can be expressed in watts, metric steam horsepower, imperial horsepower, kilocalorie per hour and British thermal units per hour.

The ratio between the mechanical power on the shaft and the power corresponding to a given velocity of undisturbed wind over the total passing surface (see Undisturbed Wind Velocity).

In alternating current, the power factor is equal to the ratio between the active power (expressed in W) and the apparent power (expressed in VA). Expressed by a decimal number (without dimensions). It allows to calculate the reactive power (in var) from the active power (in W). Note: The power factor indicates the efficiency of use of an electrical equipment, and contracts of a tariff nature may contain terms related to the billing of the different levels of the power factor. Various systems and appliances can be used to correct the power factor of an installation.

Indicator used either to characterize the evolution of the energy situation of a given geographic or economic entity over time or to compare the energy situations of different entities. Energy indicators can also serve as macroeconomic or living standards, given the weight of energy in a country's economy on the one hand and household expenditure on the other. Note: per capita energy consumption, often considered as an indicator of living standards, should be used with caution since, on the one hand, high consumption may result from mismanagement (and vice versa) And, on the other, different accounting systems and methods can lead to important differences.

Component of the wind force on a profile in the direction of the movement of this profile.

The lowest power with which a control panel can operate under correct technical conditions.

Power that can serve to cover the deviations between the expected and the actual load.

Plan to Promote Efficiency in Electric Energy Consumption.

Composed of the production of mini-hydro source (30MW), renewable energy and waste, cogeneration, low voltage production (producer-consumer) and microgeneration.