WHAT IS UV RADIATION?

Ultraviolet (UV) radiation is a form of electromagnetic radiation that comes from the sun. Humans have found use for this radiation in industry and dentistry. However, too much exposure to UV rays harms not just humans but can alter our environment because it can inhibit growth in green plants. The ozone layer that protects us from harmful UV rays has faced depletion, primarily due to certain types of chemicals we humans manufacture.

Our natural source of UV radiation:

The sun

Some artificial sources of UV radiation include:

  • Tanning beds
  • Mercury vapor lighting (often found in stadiums and school gyms)
  • Some halogen, fluorescent, and incandescent lights
  • Some types of lasers

UV radiation is classified into three primary types: ultraviolet A (UVA), ultraviolet B (UVB), and ultraviolet C (UVC), based on their wavelengths. Almost all of the UV radiation that reaches earth is UVA though some UVB radiation reaches earth. UVA and UVB radiation can both affect health but UVA penetrates deeper into the skin and is more constant throughout the year.

Benefits

The production of vitamin D, a vitamin essential to human health.

Vitamin D helps the body absorb calcium and phosphorus from food and assists bone development. The World Health Organization (WHO) recommends 5 to 15 minutes of sun exposure 2 to 3 times a week.

Risks

Sunburn is a sign of short-term overexposure, while premature aging and skin cancer are side effects of prolonged UV exposure.
UV exposure increases the risk of potentially blinding eye diseases, if eye protection is not used.
Overexposure to UV radiation can lead to serious health issues, including cancer.

Skin cancer is the most common cancer in the United States. The two most common types of skin cancer are basal cell cancer and squamous cell cancer. Typically, they form on the head, face, neck, hands, and arms because these body parts are the most exposed to UV radiation. Most cases of melanoma, the deadliest kind of skin cancer, are caused by exposure to UV radiation.

Anyone can have harmful health effects from UV radiation, but the risks increase in people who:

Spend a lot of time in the sun or have been sunburned.
Have light-color skin, hair, and eyes.
Take some types of oral and topical medicines, such as antibiotics, birth control pills, and benzoyl peroxide products, as well as some cosmetics, may increase skin and eye sensitivity to UV in all skin types.
Have a family member with skin cancer.
Are over age 50.

To protect yourself from UV radiation:

Stay in the shade, especially during midday hours.
Wear clothes that cover your arms and legs.
Consider options to protect your children.
Wear a wide brim hat to shade your face, head, ears, and neck.
Wear wraparound sunglasses that block both UVA and UVB rays.
Use sunscreen with sun protection factor (SPF) 15 or higher, for both UVA and UVB protection.
Avoid indoor tanning. Indoor tanning is particularly dangerous for younger users; people who begin indoor tanning during adolescence or early adulthood have a higher risk of developing melanoma.

Credt : National centre for Environment health   

Picture Credit : Google 

WHICH IS THE FIRST FULLY SOLAR-POWERED EDUCATIONAL INSTITUTE IN INDIA?

The Sri Aurobindo International Centre for Education in Puducherry is the first fully solar-powered educational institute in India. With solar panels installed on almost all the rooftops in the campus, the school produces three times more energy than what it consumes.  

Many schools encourage their students to switch off the fans and lights after use, plant trees and take other initiatives to save energy. However, very few go beyond just asking them to take precautions and save energy. SAICE is different. This educational institute is self-reliant in terms of energy; it meets all its energy requirements through solar power. Moreover, it produces three times the electricity it consumes and lights up many other buildings with the excess energy. And it has done so by devising and implementing a project almost entirely on its own.

SAICE is a part of the Sri Aurobindo Ashram in Pondicherry. It was in 2012 that Dr. Brahmanand Mohanty, an alumnus of SAICE, came up with the idea of making the ashram energy efficient with the help of a sustainable model.

Dr. Mohanty had a vision of developing a system that would make SAICE self-dependent for energy. With this in mind, he had a meeting with the trustees of the Ashram. They gave him the go ahead and even suggested that pilot research activities should be taken up with the active participation of the young teachers and students at the Institute. And then it all began. The whole project was conducted in two phases from 2012 to 2015.

Following this analysis, all inefficient lamps, fans, air conditioners, and computers, which had been in use since a long period of time, were substituted by more energy-efficient alternatives to lower the energy demand by more than 25 percent, without compromising on the quality and service.

With a better understanding of how much energy the educational institute was consuming, they came to the decision that a solar power plant should be installed inside the campus so as to meet all the energy demands in-house. Thus, a 17 kWp rooftop solar power plant was set up in the school by an Auroville-based solar installer.Teachers and students were involved in the entire process right from the start. They helped in the basic wiring, setting up the panels on the rooftop, and more.

Credit : The better india

Picture Credit : Google 

WHICH IS THE FIRST CARBON NEUTRAL VILLAGE IN INDIA?

Palli, a village in Jammu and Kashmir's border district of Samba, became India's first "carbon-neutral panchayat on April 24, 2022, with Prime Minister Narendra Modi dedicating to the nation a 500-kilowatt solar plant. Palli, according to the Prime Minister, has shown the way to the country by becoming carbon neutral. But what is carbon neutrality and how can it be achieved? Let's find out.

What is carbon neutrality?

We all know that carbon dioxide emissions are one of the primary causes of climate change and an increasingly warming planet. Carbon-neutrality is the state of achieving a balance between the greenhouse gases put out into the atmosphere and those removed. The term 'Net-zero' is sometimes used instead of carbon neutrality and they broadly mean the same. Increasingly, countries, companies, and organisations have been committing to achieve carbon-neutrality or net-zero carbon emission through measures such as reforestation and artificial carbon sequestering. But some environmental activists have criticised such offsetting measures as an excuse to continue polluting. If you've been wondering about the benefits of achieving carbon neutrality, there are many such as less pollution, improved air quality, better health and environment, green jobs, reducing the impact of climate change, and a greener planet.

How can it be achieved?

Carbon neutrality can be achieved by reducing the use of fossil fuels and by adopting renewable energy sources, by developing energy-efficient technologies, by adopting massive reforestation or tree-planting measures and by investing in technologies such as carbon sequestration that can remove carbon from the atmosphere. By the way, carbon sequestration is the process of capturing and storing atmospheric carbon dioxide underground permanently and safely. However, no technology or quantity of trees planted could offset the emissions currently generated globally, unless every country and every household is part of this solution.

Palli's feat

The unassuming village of Palli has made history by becoming India's first carbon-neutral solar village. It has achieved this feat with the installation of a 500-kilowatt solar plant. According to reports, the project was finished in record time (of nearly three weeks) at a cost of Rs. 2.75 crore. Under the central government's 'Gram Urja Swaraj' programme, as many as 1,500 solar panels put up on an area of 6,408 square metres will provide clean electricity to 340 homes in the model panchayat.

The green energy generated will be distributed to the village through the local power grid station, which has a daily requirement of 2,000 units.

Picture Credit : Google 

WHICH IS THE LARGEST SOLAR PARK IN THE WORLD?

Bhadla Solar Park is the largest solar park in India and in the world. Located in Bhadla, north of Jodhpur, it spans 14,000 acres, with over 10 million solar panels contributing to an operational capacity of 2245MW. The panels are cleaned by robots and monitored by humans. Bhadla is a sandy, arid region described as "almost unlivable" with normal temperatures of 46-48°C, and frequent hot winds and sandstorms. The region receives a good amount of radiation ideal for the generation of solar energy.

The entire project was divided into four phases. In the first phase of the park's establishment, solar panels were established to produce 65 MW of energy in capacities ranging from 5 MW to 25 MW. The following step of the project comprised of commissioning of the second phase of 680 MW. The first two phases of the park were developed by the Rajasthan Solar Power Park Company Limited. Saurya Urja Company of Rajasthan developed the third instalment. The project's final stage was designed by Adani renewable energy park for the capacity of 500 MW.

The auction conducted for Bhadla Solar Park recorded the price per unit fall to as low as ?2.62. Surprisingly, the price is lower than National Thermal Power Corporation (NTPC) Limited's price of ?3.20 per unit. The Indian Express quoted a senior official, "Bhadla Ph-IV Solar Park results in a historic lowering of tariffs. Phelan Energy (50MW) and Avaada Power (100 MW) have bagged projects at Rs 2.62/unit. Softbank Cleantech has won 100 MW capacity at Rs 2.63/unit".
India's has strongly started working in the direction of producing solar energy in recent years. Currently, there are over 30 massive solar projects at various stages in the country. With investments in solar projects, India is consistently working towards reducing its dependence on imported fossil fuels. Moreover, in rural areas, solar-powered lighting is proving much more beneficial than indoor lighting by kerosene. In June 2021, PM Narendra Modi said that India had increased its renewable energy capacity by 250 per cent since 2014. India has one of the fastest-growing populations and economies, which would directly benefit from increased renewable energy resources.

Credit : The logical indian

Picture Credit : Google 

What is solar energy?



 



The Sun covers our planet in light and warmth. A mixture of heat and light from the Sun can be used as energy to heat water and make machines work. Energy from the Sun is called solar energy. Solar means to do with the Sun.



The Sun is a blazing star.



This huge burning ball of gas is our nearest star. Even though it is 150 million km away from Earth, the Sun can shine so brightly that you need to shade your eyes from its light. Sunlight can feel hot on your skin. You need to wear sun cream to protect your skin.



 



 



 



 





 



 



 



Energy makes things work. You need energy to throw a ball.



Without energy, nothing works. Everything needs energy. There are many types of energy. The Sun’s energy helps plants and flowers to grow. We eat plants and other foods. The energy from food gives us the energy to throw a ball and run around.



 



 



 





 



The Sun’s heat dries wet clothes.



The Sun is packed with energy. In one hour, the Earth receives more energy from the Sun than the whole world uses in a year. This energy can also be used to generate electricity. We call this electricity solar power.


Heat from the Sun

What happens to the water in a paddling pool on a sunny day? The Sun makes it warm enough to lie in without shivering. This energy from the Sun can heat the water for hot baths and showers. Heat from the Sun can be used to heat houses too.



 





 



 



Sunlight shines through glass in this greenhouse.



Fruits such as tomatoes and exotic plants grow well in a hot greenhouse. The Sun’s light and heat pass through the clear glass windows. When the light and heat are trapped inside the greenhouse, it feels very warm.



 



 



 





 



The Sun can be used to heat up water.



Buildings can be fitted with pipes and plates that collect the Sun’s heat on the roof. These contain a liquid that heats up quickly when the Sun shines on it. The hot liquid is used to heat water. The hot water is sent through pipes to taps, ready for use.



 



 





 



 



Some colours soak up the Sun’s heat better than others.



Paint some paper plate’s different colours, including one black and one white. Put them out in the sunshine for a few hours, and then check which one is hottest, and which one is coolest. Black clothes absorb the Sun’s heat and make you feel even hotter. Solar pipes and plates are black so that they soak up lots of heat.


Electricity from the Sun’s energy



 



 



The Sun’s energy can be used to make heat and electricity. Special mirrors gather the Sun’s energy. This energy creates heat. The heat is used to turn water into steam. Steam is used to produce electricity.



 



 



 



 





 



 



Mirrors collect sunlight.



Mirrors concentrate sunlight in one place. In a solar power tower, lots of mirrors reflect sunlight onto a special collector. The collector is filled with a liquid. The liquid stays hot for a long time. It is pumped into containers. When power is needed, the liquid flows to a heat exchanger where it heats water and produces steam. The steam turns a turbine that makes electrical energy.



 



 



 





 



 



These curved mirrors turn to follow the Sun.



Power troughs have mirrored surfaces. They turn to follow the Sun. Sunlight heats a liquid-filled pipe in the centre of the troughs. This is sent to a heat exchanger. The steam produced is used to create electricity.



 



 



 



 





 



 



 



Steam from hot water turns a turbine.



Sunlight is used to boil a liquid that heats up quickly. Steam from the boiling liquid powers a turbine. A turbine is like a water-wheel which is powered by steam instead of water. The turbine drives a generator which produces electricity for homes, offices and factories. 


Electricity from sunlight



 



 



 



There are other ways that the Sun’s energy is used to make electricity. Have a look at this calculator. At the top, above the numbers, there is a row of solar cells. They use energy directly from the Sun to make the calculator work.



 



 



 



 



 





 



These solar cells turn sunlight into electricity.



The proper name for solar cells is photovoltaic cells, or PV cells for short. Photo means to do with light and voltaic means to do with electricity. Just one PV cell can power a calculator or wristwatch.



 



 



 





 



 



Solar panels are made up of solar cells.



A group of connected solar cells is called a solar panel. Between 10 and 20 solar panels grouped together are called a solar array. Solar panels or arrays work best when they face the sunlight.



 



 



 



 





 



 



 



Solar cells are made from a type of melted sand called silicon.



When sunlight shines on a solar cell, the Sun’s energy makes tiny particles called electrons jump around. When the electrons jump from one layer of silicon to another in the solar cell, electricity is created. The electricity can power a lamp or machine.


Packed with Solar Power



 



 



 



 



Solar cells make enough energy to power this torch. Hundreds of solar cells connected together make enough electricity for homes and offices, or to keep small villages supplied with electricity.



 



 



 





 



 



 



Electricity from these solar cells keeps buildings heated and lit.



This housing area in the city of Amersfoort in The Netherlands runs on electricity from solar cells. It is one of the largest solar-powered housing projects in the world. It also includes solar-powered schools anda sports centre.



 



 



 





 



 



This space station uses solar power.



High above the Earth, solar power is used to keep spacecraft working. The solar panels create enough electricity to power the International Space Station, a large spacecraft where astronauts live and work.



 



 



 





 



 



 



Making a solar cell uses up a lot of energy.



Making solar cells is expensive and uses up energy. It takes up to four years to create enough energy from one solar cell to make up for the amount of energy used to create it! In the future, the cost of making solar cells may come down.



 


Storing the Sun’s power

There are times when we need a lot of electricity, and there are times when we need very little electricity. To make sure we have electricity when we need it, scientists have discovered ways to store solar power.



 





 



 



These lamps store solar power.



A battery is a store of energy. Solar cells can store energy from the Sun in a battery. The battery releases the electricity when it is needed, such as at night. During the day, the solar cells replace the energy that has been used from the battery. This is called recharging.



 



 



 



 



 





 



 



The Sun powers up batteries in this back-pack.



Solar-powered back-packs can provide portable power for a music machine or a computer. During the day, sunlight recharges the batteries for the music machine or computer. Carrying a supply of energy in a back-pack is useful for people living or travelling in remote places.



 



 



 



 





 



 



 



 



Solar power works best in hot and sunny countries.



Places that receive lots of sunshine have the most useful solar power systems. But even in hot countries, the Sun does not shine at night. Solar power can be stored in batteries or it can be used alongside other fuels such as natural gas. 


Solar power in remote places

Solar power is especially useful for people in some remote areas of the world. Here, there may be no power stations and no network of gas or oil pipes to provide fuel for electricity.



 





 



 



This village in Angola, Africa, runs on solar power.



Solar energy is helping this village recover from the effects of war. Solar power provides street lighting and lighting for community buildings, such as the school and medical centre. It provides power for a freshwater pumping system and for hospital fridges that contain important medicines that need to be kept cool.



 



 





 



 



 



Computers can be powered by solar cells.



You probably use computers at school and at home. But in some parts of the world, there is no electrical supply to power computers. Solar-powered computers make it possible for more people there to use computers.



 



 





 



 



 



The Sun’s energy can cook a meal.



The Sun’s rays can be focused to create intense heat for cooking. A mirror or solar box cooker traps the Sun’s heat. The trapped heat cooks the food. Solar cookers mean that people do not have to collect and use up firewood for cooking.


Solar energy - On the move

Today we travel across the world in cars, boats and aeroplanes. Most of these vehicles use fuels, such as diesel and petrol. Burning these fuels releases harmful chemicals into the air. Solar power can keep us on the move and it causes less pollution.





 



Cars can fill up on sunshine.



Solar-powered cars don’t use petrol – they use sunshine. Hundreds of solar cells turn sunlight into electricity to power the car’s engine. There are even solar car races. In the American Solar Challenge, cars travel over 3,000 km across the USA, running on sunshine.



 



 





 



 



Sunlight could push spacecraft through space.



In the future, the Sun may be used to power spacecraft through space. A spacecraft would still need rockets to help it leave Earth. Once in space, sunlight would physically push on the sails to propel the craft forwards.



 



 





 



 



The Sun powers this plane.



This solar-powered aircraft is piloted by remote control. It can stay in the air for a long time to study weather patterns. The wings are covered with solar panels, providing the electricity for the aircraft’s motors. A battery provides power so the plane can fly during the night.


Our solar world



 



Roadside telephones, parking metres, flashing road signs and lights in bus shelters can all run on solar power. Houses, flats, offices and schools can all use solar energy to meet their energy needs.



 



 



 





 



 



Some schools are powered by the Sun.



Schools spend about three times more on energy than on books! Using solar power means there could be more money for books. The Star School in Arizona, USA, is completely powered by solar energy. It provides all the school’s power needs, keeps fridges cold and heats up lunches.



 


Continue reading "Our solar world"

Benefits of solar energy

The sun shines across our world every day. It will continue to do so for many millions of years. Mirrors, solar cells and specially designed buildings make it possible for us to use the Sun to supply some of our energy needs.





 



 



This solar power plant uses free energy from the Sun.



The Sun belongs to everyone, all over the world, so we can all use its energy. Although sunlight is free, solar cells are expensive to make and it is costly to set up a solar power system such as a solar power plant. However, when it is built, there is very little to go wrong with a solar power system – it just needs the Sun!



 





 



Solar power is a ‘green’ energy source.



It does not cause pollution by burning fuel and it does not make lots of noise. However, it is not perfect. To make a solar cell, rocks must be dug out of the ground and made ready to use. This uses up energy.



 



 





 



 



The Sun will last for millions of years. Other fuels will run out.



The most commonly used sources of fuel are coal, gas and oil. When we burn these fuels, they cause pollution. These fuels are also running out. When we have used them up, it will take millions of years for more coal, gas and oil to form under the ground. The Sun will continue to shine and provide power.


The future of solar energy



 



 



Scientists are looking for other ways to use solar energy safely and effectively. Could this experimental solar greenhouse tower produce enough warm air to rise up, drive a turbine and produce electricity?



 



 



 



 





 



 



In the future, solar cells may be sprayed onto road surfaces.



At the moment, solar cells are fitted onto hard panels. Advances in science may lead to solar cells that can be sprayed onto cars or road surfaces. Soft material could also be fitted with solar cells to cover any shape of house or building.



 



 



 





 



 



This solar-powered boat can study the oceans.



This boat floats on the surface during the day to recharge its solar cells. At night it can use the stored power to dive down deep to study the oceans. Lots of the Sun’s energy is trapped in the oceans. Scientists hope that one day a sea solar power plant could be used to create electricity.



 



 



 





 



 



 



The Sun shines on the Moon.



Scientists want to put solar collectors on the Moon and other planets to trap the Sun’s energy. The energy could be used to create electricity for humans on any planet.