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News, analysis, experiments, videos, games, and educational paths on the issues of energy and the environment for complete and topical information. The units of measurement used by human beings to express the quantity of energy sources are numerous.
There are measures for physical quantities and measures for the energy or heat content. Among the most well-known units of measurement of physical quantities, we find tons used for crude oil and for coal; barrels used for crude oil; cubic metres used for gas, and litres used for petrol and diesel oil.
Comparing sources of energy, with different units of measurement of physical quantities, is an extremely complex, if not impossible, task. In fact, from a kilo of petroleum we do not obtain the same amount of energy produced with a kilo of coal or a cubic metre of gas.
The official measurement unit for energy is the Joule J. The Tonne of oil equivalent is the most common at international level because it is connected to one of the most important and widely used fuels: oil. By measuring the different energy sources in terms of Tonne of oil equivalent, a comparison becomes possible and they can be aggregated, a vital operation to calculate how much energy a country consumes in a year or how much energy is still available under the surface oil and natural gas fields and coal mines.
But what is Tonne of oil equivalent? Basically, one Tonne of oil equivalent represents the quantity of heat which can be obtained from a tonne of oil.
In practice, if we measure coal in terms of Tonne of oil equivalent, it means we are considering the quantity of coal capable of producing as much heat as a tonne of oil. How can we calculate the physical quantities corresponding to one Tonne of oil equivalent of coal or natural gas? In other words, how many kilograms of coal are needed to reach one Tonne of oil equivalent of coal and how many cubic metres of natural gas to produce one Tonne of oil equivalent of gas?
To calculate that equivalence and use the units measuring physical quantities kilograms, litres, cubic metres of the different energy sources, we resort to calories. We know that one tonne of oil contains 10 million kilogram calories kg-cal , whereas one tonne of pit coal contains 7 million kg-cal. Therefore one Tonne of oil equivalent of coal, since it measures the quantity of coal containing as many kilogram calories as one tonne of oil, is equal to approximately 1.
Calculations are easier if we take, for example, vegetable fuels, containing 2. In this case, to obtain 10 million kg-cal the calorific content of a tonne of petrol we need 4 tonnes of vegetable fuels; therefore one Tonne of oil equivalent of vegetable fuels correspond to 4 tonnes of vegetable fuels.
If we know the contents, in terms of calories, of the physical units measuring the different energy sources we can calculate all the Tonne of oil equivalent equivalents. The following table reports the "Net Heat Value", i. To inform younger students about Energy and Environment, Science, Chemistry, English culture and English language, with accompanying images, interviews and videos. CLIL will no longer be a secret with"clil in action"!
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