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The energy that never ends - the difference between depleting and renewable energy

What is renewable energy and what is degradable energy? What are the origins of one and what are the origins of the other? How are energy sources usually sorted and how can they be divided differently?

Reporter: Dr. Netzah Farbiash, Vice President of Park Carso for Science

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One of the main topics in the discourse on the quality of the environment is the intelligent use of energy, and especially which energy sources we use. It is customary to separate energy sources into those that are renewable and those that are not renewable, and we are encouraged to switch to using renewable energy sources for the sake of the environment. What are those energy sources? And how are they related to the stars?


As mentioned, the energy sources are classified into renewable sources and degradable sources. Consumable sources include mainly fossil fuels (coal, oil and natural gas) and nuclear energy derived from fissile isotopes. Renewable sources include water energy (through dams, for example), wind energy, solar energy, energy production from living things (such as plants) or their products, geothermal energy that comes from the Earth's internal heat reservoir, and tidal energy - a result of the gravitational forces of the moon and sun.

Now we will sort the energy sources again into two other groups with other common denominators. In the first group: fossil fuels (coal, oil, natural gas), wind energy, solar energy, energy production from living things and their products and water energy. In the second: geothermal energy and nuclear energy. What is the logic in this sorting?

The sources of energy in the first group depend on the process that takes place in the core of the sun, a process that has almost never been seen on Earth - nuclear fusion.

What is nuclear fusion?

To understand what nuclear fusion is, we turn to the smallest particles that make up the elements: the atoms. The atoms are so small that every time we shed a tear, we leave our body much, much more opaque than the number of people living on earth (in each tear there are about a thousand billion billion water molecules; each of them consists of three atoms: two hydrogen atoms and an oxygen atom)!

When the temperatures are high enough, nuclear fusion occurs, in which, in a long and complex process, atoms of a light element combine and become atoms of a heavier element. It is mostly hydrogen that turns into helium. It turns out that in the nuclear fusion process part of the original mass "disappeared".

What did Einstein discover?

Albert Einstein, one of the greatest scientists in history, understood the relationship between mass and energy and formulated it in the well-known equation E=mc². The equation illustrates that if you convert a substance with mass (m) into energy (E), a lot of energy is obtained.

The relationship between the amount of matter and energy is the square of the speed of light (c²), i.e. 300,000,000X300,000,000 (each of the two numbers is in units of meters per second). This is a huge number! This is the process by which stars, including our sun, produce energy.

The enormous energy that is created goes through complex processes from the core of the star out to the edge of the star, and from there is emitted into space as electromagnetic radiation (light as well as types of radiation that the eye does not notice, such as ultraviolet and infrared). We see the emitted radiation as sunlight.

Plants turned into coal

Those who know how to capture the energy of light coming from the sun in a chemical process that results in sugars are bacteria, algae and plants capable of carrying out photosynthesis. They convert the energy that comes from the sun into chemical energy available to humans: when we eat plants we get sugars that are needed to power our bodies; Tree trunks and branches can be used as fuel for heating, and more.

The processes by which coal, oil and natural gas are formed take millions of years. A plant grows at a faster rate, and instead of every tree cut down for use, a new one can be planted

Plants that grew on Earth millions of years ago were buried under layers of soil, and under suitable conditions turned into coal. Oil and natural gas originate from the remains of marine organisms, such as plankton and algae, that have accumulated on the ocean floor over hundreds of millions of years. Over time, and under great heat and pressure, chemical changes occurred that changed the remains of these creatures into oil or gas.

Who lifts the water to the dams?

We have seen that oil, natural gas, coal or wood originate from the same nuclear fusion process in the core of the sun. If so, why is wood considered a source of renewable energy, and the others - degradable sources? The answer lies in the pace of the process. The processes by which coal, oil and natural gas are formed take millions of years. A plant grows at a faster rate, and instead of every tree cut down for use, a new one can be planted.

And what is the relationship between the sun and other sources of energy? In the case of solar energy, which directly converts sunlight into heat or electrical energy, this is clear. But when it comes to water that is stored behind a large dam and while falling from a height produces electricity, where does the sun come into the picture? In answer to the question: Who raised the water to the height of the clouds and allowed rain to fall, the same rain that filled the dam and made the process possible? It is the sun, which evaporates the sea water and causes the moisture in the air to rise, and eventually fall back to the ground in the form of precipitation.

And what about the second group, including geothermal energy and nuclear energy? Although they do not depend on the sun, they are directly related to the creation process of the solar system. If there were no stars in the past exploding as supernovae, heavy fissile materials, such as uranium, which we use for energy production purposes, would not have been created...

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One response

  1. Hydroelectric energy creates many problems under the guise of renewable energy - changes in the course of rivers, destruction of habitats, destruction of the environment of tribes (in remote places). Not really environmentally and human friendly energy. It can be used after a very thorough examination, which is usually not done

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