What generates Solar Power

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The Source of Solar Power


The sun’s center is full of intense nuclear activity, which generates massive amounts of radiation, and which, in turn, generates light energy called photons. Though bundles of photons are weightless on their own, they have very high momentum and energy levels.

There are various photons that travel on different wavelengths, such as visible and non-visible light. Infrared and ultraviolet light are parts of the non-visible spectrum, while white light is part of the visible spectrum.

The energy-based photons are pushed out of the sun’s center over time; about one million years from core to surface. At the surface of the sun, these photons begin their journey through space at 670 million miles per hour (just over 186,000 miles per second), to reach Earth in barely 8 minutes.

Along the way, these photons may be involved in collisions or deflections with other particles in space. They can also be destroyed and generate heat if they come into contact with radiation-absorbing objects. You can observe this phenomenon when, on a sunny day, your body absorbs photons, warming you externally.

These photons tend to be absorbed by the Earth’s atmosphere as they travel towards the surface. We feel hotter at midday, when the sun is directly above, as the photons travel a shorter path through a thinner atmospheric layer to our bodies. At sunset, the photons travel through a thicker atmospheric layer, thus providing less heat.

This is the main reason why a sunny winter day feels colder than a sunny summer day. The Earth’s angle in relation to the sun forces the photons to travel through a thicker atmospheric layer before reaching the surface.

The principles of solar electricity

At the beginning of the 19 th Century, scientists discovered the phenomenon by which certain materials can produce electric current when they are exposed to light. This phenomenon powers the modern solar panel to generate electricity. It is called the "photovoltaic effect.”                

This effect can easily be created by combining two semi-conducting layers. The first layer absorbs the sun’s heat (the photons) to generate power and excite the electrons, causing some electrons to be pushed to the second layer. When the electrons continue to jump from layer to layer, an electrical current, albeit small, is generated.

Silicon is the main semi-conducting material that makes up the solar cell. These silicon wafers are very thin and polished before being “doped” to create an imbalance of electrons in them. When the wafers are placed together, they form a solar cell, with some metal strips attached to allow the electric current to flow.

Three things can happen when a photon comes into contact with the solar cell: it is absorbed, it is reflected, or it passes through.

In the first instance, the absorption of the photon into the cell causes some electrons to “jump” between layers, creating an electrical circuit with a current. When more photons are absorbed by the silicon, it generates greater light intensity and current.

Direct sunlight allows solar cells to generate the most electricity, but cloudy days function as