carbon dioxide (CO2)
It is a natural component of the atmosphere. It is an inert gas
without colour, odorless, not toxic and not flammable. This gas
contributes more than others to the
greenhouse effect.
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cell
A device that generates electricity, a battery traditionally it consists of two plates or
conducting surfaces placed in an electrolytic fluid.
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conductor
A substance or body capable of transmitting electricity,
heat.
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direct current (d.c.)
Electric current in which electrons are flowing in one direction only.
Opposite of alternating current (a.c.)
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efficiency (%)
The ratio of output power (or energy) to input power (or energy) expressed in percentage.
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electric current
The flow of electrons through a conductor.
The unit of electric current is the Ampère (A).
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electric energy
Intermediate form of energy. Electric energy is generated by
thermoelectric, hydroelectric,
electronuclear, wind,
solar photovoltaic
and
geothermal plants.
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electric field
Force field surrounding an electric body or moving magnet.
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electric power
Electric energy produced per unit time.
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electromagnetic spectrum
The entire range of wavelengths or frequencies of the electromagnetic radiation
extending from gamma rays to the longest radio waves including visible light.
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electronuclear power plants
Plant in which the energy
from the heat produced by nuclear fuels is converted into electricity.
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ENEA
Ente per le Nuove tecnologie, l'Energia e l'Ambiente. It is the italian agency
for new technologies, energy and the environment.
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energy
The ability to do work.
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fossil fuel
Coal, oil and natural gas. Fossil fuels derive from the slow decomposition
of old plants or animals.
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fuel cell
A device combining a fuel with oxygen in an electrochemical reaction to generate
electricity directly
without combustion.
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olio combustibile
Frazione pesante della raffinazione del petrolio, utilizzata
come combustibile, sempre più spesso a basso tenore
di zolfo al fine di limitarne gli impatti negativi per l'ambiente
in termini di emissioni atmosferiche (principalmente: SO2, NOx,
particolato).
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geothermal
power plant
Plant that uses geothermic heat to produce electric energy.
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greenhouse effect
The global warming resulting from the absorption of infrared solar radiation by carbon dioxide
and other trace gases present in the atmosphere. (The term is a misnomer in that in actual greenhouses the warming
comes primarily from restrictions on air flow).
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greenhouse gas
Gases which contribute to the greenhouse effect by absorbing infrared radiation
in the atmosphere. These gases include carbon dioxide, methane, nitrous oxide (N2O),
water vapour, and a variety of chlorofluorocarbons (CFCs).
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grid connected photovoltaic system
A photovoltaic system connected to
the distribution network of electric energy by an inverter.
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hydroelectric plant
Plant that generates mechanical energy and then electricity by converting the energy of moving
water. Mechanical energy is converted into
electric energy for civil or industrial use.
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infrared radiation
The part of the electromagnetic radiation whose wavelength range lies between 0.75 micrometer to 1000 micrometers.
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insolation
The rate at which energy from sun reaches the earth's surface.
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inverter
Device that converts d.c. current in alternating current (a.c.).
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Joule
The unit of energy or work. One joule is equal to one Watt second
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kW (kilowatt)
A unit of power equal to 1000 Watts (energy consumption at a rate of
1000 Joules per second.
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kWh (kilowatthour)
It is a measure of electricity consumption equal to the amount of power multiplied by
the amount of time the power is used.
Energy equivalent to one thousand watts delivered over the period of one hour. Standard method of measuring electrical energy.
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natural gas
Natural gas is a mixture of hydrocarbons, mainly methane, CH4.
It is extracted from underground deposits and transported mainly through
pipelines.
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nonrenewable fuels
Fuels that cannot be easily "renewed". Oil, natural gas, and coal are nonrenewable fuels.
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n-type semiconductor
A semiconductor produced by doping an intrinsic semiconductor with an electron-donor impurity (e.g., phosphorous in silicon).
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nuclear fuel
Fissionable material, used in a nuclear reactor.
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ohm
The unit of electrical resistance. It is the resistance of a circuit in which a potential difference of one volt produces a current of one ampere.
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ohm's law
For any circuit the electric current is proportional to the voltage and inversely proportional to the resistance.
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ozone
It is a gas whose molecules are formed from 3 oxygen
atoms, rather than 2 like in the case of the oxygen that allows us to
breathe. Ozone is useful in the high layers of the atmosphere,
because it is in able to filter and absorb the ultraviolet radiation
that hits the Earth, but in the low layers of the atmosphere (in the troposphere)
it must considered as a pollutant, since it damages vegetables and many materials,
and it is involved in the reactions of formation of acid rain
and can provoke respiratory problems.
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peak power (Wpeak)
The peak power is the amount of power output that a photovoltaic module
produces at the operating temperature of 25 degrees Celsius in full
sunshine (irradiance) of 1000 watts per square meter (in a clear summer
day with sun overhead and the cells facing directly
towards the sun). Unit: Watt (W), also written Wpeak by professionals in the field.
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photon
The elementary particle of electromagnetic energy; light.
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photovoltaic
The term refers to technological
systems that convert solar radiation directly into electric energy
(photovoltaic systems)
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photovoltaic cell
A conversion device that changes light into electrical energy.
The cell consists of layers of semiconductor materials fabricated to form a junction
(adjacent layers of materials with different electronic characteristics) and electrical contacts.
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photovoltaic device
A device that converts light directly into dc electricity.
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photovoltaic module
The basic building block of a photovoltaic device, which consists of a number of interconnected solar cells.
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photovoltaic system (array)
A number of photovoltaic modules that are electrically connected
in a series and/or in parallel so as to provide the desired power and voltage.
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photovoltaic system efficiency
The ratio of the produced electric energy to the incoming solar energy.
It is expressed in percent (%). Typical efficiency for photovoltaic cells, in
amorphic, polycrystalline, monocrystalline silicon, vary between 6% and 18%.
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power
The rate at which energy is consumed or produced. The unit is Watt.
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radiometer
Instrument for the measurement of electromagnetic radiations.
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renewable energy
Energy produced from virtually inexhaustible resources such as the sun.
For example, solar radiation, biomass, wind, water, or heat from the earth's interior are renewable energy resources.
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semiconductor
A material that has a limited capacity for conducting an electric current.
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silicon (Si)
A semi-conductor material commonly used to make photovoltaic cells.
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solar concentrator
A device which uses reflective surfaces in a planar, parabolic trough, or parabolic bowl configuration to concentrate solar radiation onto a smaller surface.
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solar constant
The radiation arriving from the sun at the edge of the Earth's atmosphere. The accepted value is about 1350 watts per square
meter.
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solar energy
The electromagnetic radiation emitted by the sun. The part of solar
radiation that arrives on the earth
is indicated by the solar constant.
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solar thermic electric power
The indirect conversion of solar radiation into electricity by solar collectors, a heat engine, and electrical generators.
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solar tower
A technology for the exploitation
of the solar energy. A system of mobile mirrors concetrates the light on a boiler on the top of the tower.
The boiler reaches very high temperatures.
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stand alone photovoltaic system
Photovoltaic system not connected
to the electric network. It normally has batteries.
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thermoelectric power plant
It transform thermic energy produced by the combustion of fossil fuels into electric energy.
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Volt
Unit of electrical tension or potential difference.
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watt
The unit of power.
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wind power plant
Arrays of interconnected wind turbines which generate electricity for delivery to a utility transmission-distribution system.
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wind energy
Energy from the wind caused by moving air masses. The movement is
caused by temperature and pressure differences in the atmosphere, which are
tied to the not uniformity distribution of solar heat.
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