Explanation of Solar Energy

One of the most used and talked about types of energy is solar energy. It is one that has kept scientists on their toes on how it can be harnessed more effectively. As history will have it, it has been in existence and used for a very long time.

History of Solar Energy

The sun is the source of solar energy. It is said to be a big gas ball whose core dissipates solar radiation as a result of nuclear fusion. This solar radiation is what results in the solar energy that falls on earth. So, it’s safe to say that solar energy dates back to when the sun started existing; which is most probably before the existence of mankind.

Since time immemorial, solar energy has been in use by plants, animals, and people. It has been a major contributor to plant growth, which in turn provides resources (like food) to help animals and people grow. 

In early times, humans improvised other ways of utilising solar energy. For example, in the early 7th century B.C., people were said to have used magnifying glasses to focus the sun rays on a bunch of wood to produce fire. Also, in the 3^rd century B.C., the Romans and Greeks were said to use solar energy to light torches for religious activities.

In 1897, an American engineer named Frank Shauman invented a solar engine that used solar energy to drive a small steam engine. He went on to build a solar thermal power station in Egypt. So, the exploitation of solar energy has been on even before the advent of solar panels, concentrators, and other related technologies.

Now, let’s take a look at how solar energy can be defined.

Definition of Solar Energy

Solar energy is simply energy from the sun. It is the sort of electromagnetic radiation that is emitted from the sun. This electromagnetic radiation majorly includes infrared rays, visible light, and ultraviolet rays.

Solar energy can also be put as the ability for the electromagnetic radiation from the sun to do work.

How Solar Energy Reaches the Earth?

The sun is said to be several miles from the earth. As the sun radiates its energy which is in the form of electromagnetic radiation (at high frequency), it undergoes absorption, reflection, and scattering before getting to the earth’s surface. This absorption, scattering, and reflection are due to the atmosphere and cloud it passes through.

By the time the electromagnetic radiation gets to the earth (at a lower frequency), it also gets absorbed and diffused by the earth’s atmosphere and clouds. On getting to the ground level of the earth, only low-frequency electromagnetic radiation (majorly Infrared rays, Visible Light, and ultraviolent rays) is left.

In the end, all that is available for use on the ground level of the earth is majorly the Ultraviolet rays, Visible light, Infrared rays, and some other forms of Electromagnetic radiation.

Is Solar Energy Renewable?

Solar energy is from a natural source (the sun) and does not run out. Day after another, the sun emits energy in a clean and environmentally friendly way. So, yes, solar energy is an example of renewable energy. It is also inexhaustible.

Definition of Solar Power

Generally, energy and power are different but are very interrelated. So are solar energy and power. Without solar energy, there would be no solar power.

So, solar power is the power that is produced from the solar energy generated from the sun. A common example of solar power is the electricity generated using solar photovoltaic panels. Solar power can also be put as the rate at which solar energy is used to do some work.

Definition of Solar Irradiance

This is somewhat similar to solar power except that it is much more specific in an area. Solar irradiance is the solar power generated per unit area. In other words, it is the amount of solar power than can be generated per 1 square meter area. It is measured in W/m².

Solar irradiance varies across the earth because solar energy also varies. An instrument called an irradiance meter can be used to measure the solar irradiance of a location.

Definition Solar Irradiation

Solar irradiation is similar to solar energy except that it focuses on a specific area. It is the amount of solar energy per unit area.

In other words, it is the amount of electromagnetic radiation from the sun that falls on 1 square meter of the earth’s surface. It is measured in Whr/m². Solar irradiation is also called solar insolation.

How Much Solar Energy Reaches the Earth?

We are able to safely use solar energy because the sun is about 93 million miles away from the earth, it is spread over in the outside space and passes through air masses before getting to the ground level of the earth.

The solar irradiance at the outer part of the earth’s atmosphere is said to be around 1368W/m², but on getting to the earth, it reduces to a value of about 1000W/m².

Solar irradiance varies, as there is variation in sunlight and different weather conditions across the earth.

The Uses of Solar Energy

• Photosynthesis: Plants undergo photosynthesis to generate glucose and oxygen. Oxygen is what animals retain to survive. But for photosynthesis to occur, water, solar energy (sunlight), and carbon dioxide are needed. The plants convert solar energy into chemical energy to aid the photosynthesis process. So, without solar energy, plants can’t undergo photosynthesis; and without photosynthesis, there could be a depletion of oxygen and food for animals and mankind.

• Heating: The heating nature of solar energy is one that has been in use for a long time. In the late 19^th century, solar water heaters were used to provide hot water for domestic use. In recent times, the heating nature isn’t just for providing hot water or heating one’s home but also for cooking.

• Electricity generation: This is one of the most usable examples of solar energy. It involves the use of solar photovoltaic panels to generate electricity. The electricity generated from the solar panels can be used to charge your battery, power your home appliances, energise your lighting system, and much more.

• Transportation: This is one of the most recent and innovative uses of solar energy. Cars, buses, airplanes, and trains are now been powered by solar photovoltaic panels using solar energy.  For example, the world’s first solar train is fully solar-powered and can carry over a hundred people or more.

Advantages of Solar Energy

• Renewable: Solar energy is from a natural source and does not run out. The sun will keep supplying solar energy and there is no indication it will ever deplete.

• Abundant: Even with the effect of weather variation, it is still the most abundant form of energy. It is everywhere.

• Alternative form of energy: In addition to the traditional form of energy (like fossils), solar energy provides us with alternative forms of energy to use. No need to be all dependent on the non-renewable forms of energy

• Little maintenance cost: Since there are no moving parts, the solar photovoltaic (PV) systems require little maintenance such as cleaning the solar panels and battery terminals, checking for loose connections, and so on. All these maintenances are professionally menial and can be done at a low cost.

• Environmentally friendly: Unlike the conventional power systems, solar power systems do not cause noise pollution as it does not have moving parts. It does not emit gasses like CO2 which is known to be a contributor to global warming.

• Generate your own electricity: Using solar panels, you can generate electricity in your homes without having to fully depend on conventional utility companies. So, it helps improve the reliability of electricity supply to your home.

• Diverse usage: It has diverse uses like heating, generating electricity, flying airplanes, and so on.

• Job creation: More people are needed in the research, installation, sales, and manufacturing of solar energy systems. So, more jobs are created

• Easily adaptable: Since solar energy is free and spread across the surface of the earth, the solar PV system can easily be adopted by nearly anyone. Solar PV installation isn’t as complicated as conventional power systems.

Disadvantages of Solar Energy

• High initial capital cost: Even though the cost of solar power system components is reducing, it is still costly. So, high investment is required to install a solar power system.

• Requires lots of space: Solar PV panels have very low efficiency. So, lots of space is needed for solar panels to generate a certain amount of power. To generate more power, you would need more solar panels, and inevitably more space. And not all spaces are suitable for installing solar panels as the solar PV panels would have to be situated where there is access to sunlight.

• Pollution: Solar PV systems can also be a cause of pollution, but less than that of non-renewable energy systems. For example, toxic materials associated with manufacturing batteries and solar panels. They can indirectly pollute the environment.

• Depends on the weather: During cloudy days or at night, there is little or no supply of solar energy. So, at those times, there is no solar energy to use.

• Requires expensive storage facility: Since solar energy can be affected by weather, it is best to save some of the energy when available, for later use. For solar PV systems, this will require a storage facility (like a battery bank), which can be expensive.

Notable Solar Energy Organisations in the World

Solar Organisation	Headquarters
International Solar Energy Society (ISES)	Freiburg im Breisgau, Germany.
Solar Energy Industries Association (SEIA)	Washington, D.C., United States
International Solar Alliance (ISA)	India
SolarPower Europe	Brussels, Belgium
American Solar Energy Society (ASES)	Colorado, United States
Solar Cookers International (SCI)	Sacramento, California, United States.
Middle East Solar Industry Association (MESIA)	United Arab Emirate

Notable Solar Energy Research Centers in the World

Research Centers	Location
Clean Energy Institute (CEI)	University of Washington, Washington
Florida Solar Energy Center (FSEC)	Cocoa, Florida.
Plataforma Solar de Almeria (PSA)	Almeria, Spain