What it is
The energy carried by sunrays as a consequence of nuclear reactions (hydrogen fusion) and transmitted to the Earth as electromagnetic radiation is called solar energy. Electromagnetic radiations are made of photons. A photon is a neutral particle that spreads into the air at a speed of 300,000 km/sec, with an energy that depends on its frequency and a mass that is considered as void when at rests (when it is not moving). The intensity of solar radiations that arrive every year to the earth’s surface amounts to 80 thousand billion tons of oil equivalent (the so-called TOE, that indicates a quantity of energy that equals the energy produced by a ton of oil). This quantity is infinetisimal if compared to the energy produced by the Sun thanks to nuclear reactions. But it is also a very large quantity, if you only consider that the world energy demand amounts to 8 billion TOE a year. From the flow of solar energy, the following are derived: biomass energy, through the photosynthesis process; hydraulic energy (the Sun, in fact, is the motor of the water cycle); wind energy from which, in turn, wave energy derives. Anything, starting from what we eat every day, is directly or indirectly linked to it. Even fossil fuels, which derive from chemical-physical alterations of prehistoric living organisms, contain solar energy. Solar radiations, although they only reach a maximum power of 1 kilowatt per square meter (soil irradiation in a clear day, sunny, at midday), are the most abundant and clean energy source on the Earth.
Special reports
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13 May 2013
Small steps, great footprints
Have you ever wondered how much space is taken up by an apple or a steak?...
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18 May 2011
Artificial photosynthesis
The history of science and technology is packed with discoveries and inventions inspired by nature...
27 September 2012
Over 7 billion people on Earth
Demographers have estimated that on 31 October 2011 world population...
18 January 2016
Ten years of oil demand
Eni has recently published the 14th edition of the 2015 World Oil and Gas Review...
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4 November 2009
Ecological house
At present, it is more and more difficult to assure the comfort standard...
10 September 2020
A simple and ingenious invention
There are objects so simple and ordinary that we forget their existence when we don't need them. Their presence is…
17 March 2020
Energy and renewable sources: what is the current status?
The unstoppable growth of renewable sources continues…
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13 May 2013
Small steps, great footprints
Have you ever wondered how much space is taken up by an apple or a steak?...
-
18 May 2011
Artificial photosynthesis
The history of science and technology is packed with discoveries and inventions inspired by nature...
-
27 September 2012
Over 7 billion people on Earth
Demographers have estimated that on 31 October 2011 world population...
18 January 2016
Ten years of oil demand
Eni has recently published the 14th edition of the 2015 World Oil and Gas Review...
-
13 May 2013
Small steps, great footprints
Have you ever wondered how much space is taken up by an apple or a steak?...
From the Multimedia section
Facts
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Bio-climatic architecture
Solar energy is playing a vital role with reference to bioclimatic architecture...
The photovoltaic train
In Italy the PVTRAIN project by Trenitalia (co-financed by the European Union) plans...
The plant of Almeria
In the Tabernas desert, 30 km north-east of the Andalusia town of Almeria (Spain)...
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Italian offshore wind farm
The first Italian wind farm will be installed in the waters of the Strait of Otranto...
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An artificial geyser
Electric and thermal power produced from geothermal energy depend on the existence of underground infiltrations...
Hydrogen from biomass
Hydrogen is an energy carrier that allows to generate energy in an environmentally sustainable way...
A hydrogen house
In Settimo, a municipality close to Turin, the first Unité d’Abitation has been created...
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16 May 2011
Bio-climatic architecture
Solar energy is playing a vital role with reference to bioclimatic architecture...
The photovoltaic train
In Italy the PVTRAIN project by Trenitalia (co-financed by the European Union) plans...
-
The plant of Almeria
In the Tabernas desert, 30 km north-east of the Andalusia town of Almeria (Spain)...
-
Italian offshore wind farm
The first Italian wind farm will be installed in the waters of the Strait of Otranto...
-
16 May 2011
Bio-climatic architecture
Solar energy is playing a vital role with reference to bioclimatic architecture...
-
The photovoltaic train
In Italy the PVTRAIN project by Trenitalia (co-financed by the European Union) plans...
-
The plant of Almeria
In the Tabernas desert, 30 km north-east of the Andalusia town of Almeria (Spain)...