Our Universe is mainly made up of matter and energy. Energy is the only factor responsible for all the actions of the cosmos. Our civilization primarily depends on energy consumption, as the energy consumption rate has increased with human society’s growth, bringing drastic changes in our universe’s development.
We can not imagine how much more this civilization will evolve in the future with this rate of enormous energy consumption. This is why people are trying to find alternative and reliable sources of energy and available energy sources. Scientists are trying to find renewable energy sources (used repeatedly without depletion).
In this article, we are trying to discuss the most efficient renewable energy source that will be available for many more centuries: Solar Energy.
Sources of Energy Consumption with Time:
The scenario of Global Energy consumption changed rapidly: In the early 19th century, there was only one primary energy source, wood. As the era started to
Progress, another energy source, coal, came into use. Slowly, in the mid 19’s, fossil fuels’ primary consumption of energy was taken by fossil fuels; this included oils, natural gas, and coal. However, as these fossil fuels are non-renewable, people fear that excess use will end soon. People needed to find an alternative renewable energy source that would last for a more extended period. In search of an alternative energy source, we found nuclear, solar, wind, geothermal, hydroelectric, biogas, etc. Solar energy has become a cost-effective, high-efficiency, and long-stable energy source among these renewable energy sources. In our discussion, we shall discuss:
- What is solar energy?
- How does solar energy reach Earth?
- How can we absorb solar energy?
- Can solar energy be converted to other energy sources like heat, electrical, etc.?
- Storing of Solar Energy?
Understanding Energy before Solar Energy:
Before we jump into solar energy, we must know the essence of energy. If someone asks what the definition of energy is, we say it’s “The ability to do any work.” Behind any action, movement is a fundamental necessity. Simply put, this movement through a particular amount of force refers to work done. To accomplish this action or work, energy is required. For example, When a car runs, its movement refers to the vehicle’s job or activity, and the reason behind its move is its energy; in this case, the energy source is fuel.
What is Solar Energy:
Do you know that the temperature of the surface of the Sun is 6000 Kelvin? But the question is where from an extensive amount of heat energy is produced? The core of the Sun is tightly bound with a tremendous amount of pressure. Nuclear fusion takes place inside the Sun, where Hydrogen converts to Helium. Heat and photons(light) release enormous amounts of energy during this process. Some of this heat and light energy reaches Earth daily, known as Solar Energy. This energy makes the Sun a reliable and abundant source of renewable energy.
How Solar Energy Reaches the Earth:
Solar energy goes to our Earth in light and heat; these light waves are scientifically known as electromagnetic radiation(waves having electrical and magnetic fields perpendicular to each other and perpendicular to the dir. of propagation). When these light waves reach Earth’s atmosphere, they contain about 50% infrared, 40% visible, and 10% ultraviolet light. When this energy goes into Earth’s atmosphere, it is calculated how many solar power watts can be generated when sunlight falls in a 1-meter square area. Hence, its unit is Watt/meter square. At the top of Earth’s atmosphere, it receives the power of 1.4 KW/msg. But this power reduces to 1 KW/msg. When it reaches the Earth’s surface, the particles present in the atmosphere are water vapor, gas, and dust. The reflection of light waves is also a reason for reducing solar power.
Utilization of Solar Energy:
Though you may think solar energy consumption began after the invention of new electrical instruments like solar panels, solar energy consumption has been going on for ages. Trees and animals have been absorbing solar energy to function daily and still depend on sunlight directly or indirectly. As solar energy is available in high abundance on Earth, and we can not absorb it naturally, many different techniques have been introduced and are evolving to utilize it. Let’s discuss some of them-
1. Conversion of Solar Energy to Electrical Energy: Unlike metals and insulators, a semiconductor material exists where the current doesn’t flow until external energy is introduced. However, whenever some external electric field, light radiation, or thermal energy is applied to its current and starts flowing through a semiconductor, semiconductor behavior is the fundamental principle of solar energy to electrical energy conversion.
We can convert solar energy to electrical power from solar cells using this principle. Solar cells are made up of semiconductor materials like silicon. When sunlight falls into a solar cell, electron emission takes place, and further, we get the flow of electrons, which is nothing but electricity. However, we cannot get enough electricity from one solar cell for practical use. Many solar cells are connected in series to get more electricity. Such an arrangement of solar cells is known as solar panels. This energy can be used further in electrical appliances, electric vehicles, etc.
2. Conversion of Solar Energy to Thermal Energy: Solar energy is converted to heat energy for domestic or commercial applications like heating swimming pools, producing domestic hot water, space heating, or supplying other heat consumers. When solar radiation is incident on a solid body, it absorbs the solar radiation and emits it in the form of heat; in this process, when light falls on a solid body, the body’s atoms start oscillating. This is the basic principle of solar-to-thermal conversion.
An energy collector or Sunlight collector is designed with a mirror, lens, and heat exchangers to concentrate and absorb solar energy (radiant energy from the Sun). The fluids are passed through the sunlight collector to absorb the heat from the collector and get heated. This hot fluid can be transferred to a heat engine to generate electricity.
The above discussion was about the direct conversions of Solar energy to electrical and thermal energy. Solar power, converted into electrical energy, can be further converted into mechanical energy, such as electric vehicles, industrial machines, robots, etc.
Storing of Solar Energy:
Solar energy storage comes into action for two reasons: 1. Solar panels cannot generate any point at night or on cloudy days.
When the energy generated by solar panels is higher than that of the required power,
Storing solar energy in the form of heat: The most straightforward way of storing solar energy is to convert it into thermal energy and utilize it for heating fluids like water. This heated fluid holds the heat energy several times. A residential solar hot water system is the most outstanding example of storing solar energy in heat energy.
Storing solar energy through battery: We are familiar with photovoltaic cells that convert solar radiation to electrical power. This electrical energy can be stored in a shower as chemical energy. When charging a rechargeable battery, it takes electrical energy and converts it to chemical energy through a chemical reaction. It converts the stored chemical energy to electrical energy through a chemical reaction during discharge.
Battery storage systems have rapidly improved with the increasing popularity of solar energy and electric vehicles. Earlier, lead-acid or nickel-cadmium batteries were used to store energy, but in the early 1990s, a revolutionary battery called lithium-ion batteries was developed. Today, Li-ion is considered the most popular and promising battery. It is a high capacity(energy density), lightweight, low maintenance, and low self-discharging battery. Earlier, Li-ion was more expensivets price decreased rapidly with tthe improvement of echnoltechnologiesg the past decades, its price has fallen immensely to about 90%. The main reason for the fall in The cost of lithium is the increasing popularity of electric vehicles worldwide. Electric vehicle companies deliberately try to make the most efficient and cost-effective battery to minimize their cars’ overall cost.
Conclusion
With the evolution of human civilization, new technologies and inventions are being utilized to consume and store solar energy. For example, we use solar panels or heaters. However, these techniques are not enough to utilize or destroy all the solar energy that reaches the Earth. The next line will astonish you when you know that 430 quintillion Joules of energy hit the Earth each hour. Can you imagine how much power 430 quintillion Joules is?
It is nearly equal to the total energy humans use over a year. You can imagine how much solar energy our Earth receives every hour. Our current technology can only utilize a tiny fraction of this vast energy source. So, with the increasing energy demand, our next motive should be: 1.) improving our present technology, and 2) finding more efficient technology to increase energy consumption and utilization.