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Solar Energy

by | Mar 10, 2022 | Renewable Energy

Introduction

Solar energy is the energy drawn directly from the Sun’s energy. It is the base of renewable energy sources, which are dependent on solar energy, like wind and ocean thermal energy. These renewable energies are a different form of solar energy, converted when they reach the earth’s surface. The energy comes from the Sun in the form of electromagnetic radiation, the nuclear fusion reaction that occurs inside the Sun when the nucleus of hydrogen fuses into helium nucleus and starts a chain reaction and releases an enormous amount of energy and escapes into space is what causes the production of Solar energy. It is a universal and unlimited source of energy. Animals directly or indirectly use solar energy. Plants use solar radiation to produce energy and make energy available in the ecosystem. In the absence of solar radiation, there is no life possible on earth. Wind, ocean thermal, and biomass are the indirect source of solar energy. The solar energy input on earth is 1,67,000 times higher than current consumption.

What is Solar Radiation?

Solar radiations are electromagnetic radiations that are also referred to as solar resources. Electromagnetic radiation is composed of different wavelengths of light such as gamma, X-rays, UV, Visible, IR-ray are released from the Sun and reaches the earth’s surface. Some of the solar radiation is absorbed and reflected by the clouds and upper atmosphere, and the remaining reaches the earth. The solar radiation that reaches the earth is 50% visible light, 45% of Infrared rays, and the remaining amount of UV and other radiations.

The electromagnetic spectrum of radiation:

 

The electro magnetic spectrum of radiation

 

EM radiations are the transverse moving waves with a speed of 3x108m/s in a vacuum. The E stand for electric, and M stands for the magnetic field that varies sinusoidally, and both are perpendicular to each other and propagation direction.

Types of Solar Energy

Solar Thermal Energy

Solar thermal technologies are the most effective and varied renewable energy technologies. That can be based on heating or temperature that range from(<70C) to (200C), such as solar air conditioning, solar cooking, solar space heating, and solar thermal power generation. Solar heating uses most of the thermal technologies. In this type, heat is used, which is produced by solar radiation by concentrating it on certain regions.

It is categorized into concentrated (Solar cooker, electricity production, and process heating) and non-concentrated (Water heaters and solar dryers) thermal technologies.

Concentrating Solar Power

Concentrated solar power is generated by using optics that absorb the sunlight and concentrate it on a solar energy converter- for example – Parabolic trough collectors (Concentrated), Sterling Engine (Concentrated with moving focus).

Concentrating Solar Power

Concentrating Solar Power

Photovoltaic Solar Power

It is a device used to convert solar radiation into electricity directly with the help of a photovoltaic cell. The individual photovoltaic device is referred to as a cell.   Its size is small and able to give power around 1 to 2 watts. It is composed of silicon semiconductors, doped with another element like phosphorus or boron that can create electron movement and produce current. The thickness is less than 4 hairs of humans. These cells are placed between protective material with glass combination. Together with many single photovoltaic cells in chain arrangement create large units called panels or modules that boost electricity production. The module can be operated singly or in the array.

Photovoltaic_solar_cell

Stand-Alone Solar PV System

How Does Solar Energy Work?

Solar energy is the electromagnetic radiation used to produce electricity or heat and is used for various purposes. The electricity is produced by using a photovoltaic system by direct conversion of sunlight into electricity. In contrast, heat is produced by concentrating the solar radiations on a certain point of the receiver, raising the region’s temperature, and producing the heat, which is transferred to the system by conduction and convection mechanism..

The solar photovoltaic produce electricity by the photovoltaic effect. It is a chemical and physical phenomenon that produces electromotive force in the heterogeneous material (silicon-Phosphorus and silicon boron), illuminating a specific wavelength. Such action produces an electric current in the material after exposure to the sunlight. Silicon is a semiconductor and is capable of converting sunlight into electric current.

Government Schemes and Policies (US & India)

As energy demand rises and fossil fuel reserves deplete, their energy production from different resources has increased, like solar energy. Different countries use different policies and technologies to produce electricity. A country like the USA increased the electricity production from solar radiation in 2008 to 0.34GW, and now it has grown to about 97.2 GW, which is sufficient to power the approx. 18 million average homes of America. The solar jobs in America have increased 167%  over a decade.

India is a solar power-rich country due to its geography. It is a tropical country where sunlight is perpendicular to the surface, they use it to produce electricity as it receives maximum solar radiation. In the year 2018, the solar capacity reached 26GW. India achieved the set targets  20GW before 2022, and the said action reduces coal-based electricity production by about 18%.

In Jan-2015, India increased its solar capacity by about 100GW and invested US$100 billion. Including 40 GW through the rooftop by 2022. In Jan-2016, the Prime Minister of India and franc laid the foundation of the ISA-international solar alliance in Gwalpahari Gurgaon. This ISA focuses on solar energy development and promotion in countries present in the tropic of cancer and the tropic of Capricorn. The alliance was declared at the Cop21 climate summit with 120 countries.

Is Solar Energy Reliable?

Solar energy is the energy obtained from the Sun used to produce electricity and heat and used for different purposes. The electricity produced from solar energy is dependent on solar radiation. It is continuously coming from the Sun without any spent money. Solar radiation influences power production. Because solar radiation is available in the daytime, it is more prominent in the equator region and good for tropical countries, but during monsoon, the solar influx reduces due to cloud conditions. In temperate countries like Canada, the USA, Netherland, their power output from solar radiation is not as much. New recent advancements are achieved in photovoltaic systems (thin-film solar cell, III-V solar cell, and Next-generation solar cell) to harness solar power by overcoming the diffused sunlight, which gives us hope that solar energy in the future is now and in the future can be a reliable energy source.

 

 

 

Author

  • The author has done a master's in Environmental science and is currently working as chief Environmental Advisor with New Delhi State Government.

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