The earth depends on the sun for life and light. The sun is our main source of energy, and this is called solar energy. The core of the sun is extremely hot.
The sun produces its energy by combining hydrogen into helium, within its core. This process is called a ‘nuclear fusion’. The solar energy that we use has reduced from about 1,300 watts to about 1000 watts by the time it reaches Earth, which makes it safer and easier to harness.
Solar energy is a renewable, clean and natural energy source that in itself does not cause pollution to the environment.
Plants convert sunlight into energy through a process called ‘photosynthesis’. During photosynthesis, the plant uses sunlight, carbon dioxide and water to produce energy in the form of sugar molecules and oxygen.
Solar energy is used for electricity and heating purposes. Solar technology includes solar heating, solar architecture, solar electricity, and solar thermal electricity. These technologies can either be passive solar or active solar energy capturing mechanisms.
Solar panels are a collection of photovoltaic cells that trap sunlight. The process of producing electricity through sunlight is called photovoltaic. ‘Photo’ means light, and ‘voltaic’ means electricity.
When solar energy is used for heating purposes it is called thermal energy. Solar thermal energy has been used for water heating, space heating, and space cooling.
Passive solar technology is when buildings and spaces are designed to store and heat by building them to face the sun. Active solar technologies include solar electricity and solar thermal electricity panels that use the photovoltaic cells to capture energy.
Greenhouses use solar energy to help plants grow. Greenhouses look like houses made of glass that help plants grow by trapping the sun’s energy through its roof and walls.
The heating mechanism in greenhouses is called convection. During this process, plants themselves release some of the heat that they absorbed, and this too gets stored within the greenhouse.
Greenhouses can be either plastic or glass. Glass greenhouses are more technologically advanced and often have lighting, heating and cooling systems, while small-scale farmers and homeowners usually use those made of plastic.
We use solar energy on a daily basis and sometime do not even notice it. When we dry our clothes in the sun or use calculators with the little panels on the top corner, we are using solar energy.
Some countries like Australia use solar panelled cars and even boats. These vehicles trap solar energy and convert it to electricity that powers the battery. These cars are very light and are built mostly for racing purposes.
Solar boats use Solar Wing technology that harnesses sunlight and converts it to electricity. The whole boat is controlled through advanced computer systems that rotate the wings to catch maximum sunlight. The boat is powered through the by generators and electric motors that are powered by solar energy.
Domestic heating systems also use solar power to generate hot water throughout most of the year, and can even heat indoor swimming pools. However since the power of a solar heating system depends on the amount of sunlight being received, during winter there is little or no hot water being generated this way.
Solar cookers or solar ovens are used for cooking and sterilizing of foods and drink. Solar cookers and ovens are economical, do not cause pollution, and are used to reduce the cost of fuel, (gas and firewood) especially for low-income communities.
Space based solar power (SBSP) use solar satellites to collect solar energy to send it back to Earth. These satellites orbit the earth and collect solar energy, which they transmit through microwaves, to antennas in solar receiving stations found on the earth’s surface. These solar satellites are great because they are in direct view of the sun, so they produce solar power throughout the day and night. But they are expensive and so they are not as popular as other methods of harnessing solar power.
Solar energy is also used by building houses and factories to store heat in their walls, windows and doors during winter, and castoff this heat during the summer. This way, the buildings are well heated or cooled depending on the season.
A photovoltaic power station is called a ‘solar farm’ or ‘solar park’. These farms have a system of photovoltaic panels that supply electricity through an electric power grid. Through advanced photovoltaic technology they are able to harness solar energy to supply electricity for large scale agricultural purposes.
Wineries have also started using solar power by installing solar electric power plants to provide electricity for the winery, and the surrounding area. The roofs of the wineries act as platforms on which large numbers of photovoltaic solar cells are placed to harness electricity.
A parabolic dish or parabolic reflector is a type of reflective gadget that either collects or distributes types of energy such as sound, light or radio-waves. It is special because of its unique parabolic shape that is it is curved in a way that when the energy hits it is able to reflect to a mid or central point.
Parabolic reflectors are found in a variety of things like telescopes, satellite dishes, parabolic microphones and even some lighting devices.
Solar power can also be used to as a water treatment method. The process of making saline follows the distillation method using solar energy.
Another method of water treatment is exposing water in plastic filled bottles to direct sunlight. This is called solar water disinfection (SODIS). Solar energy can also be used to treat wastewater in water stabilisation ponds.
In 1860 - 1881 Auguste Mouchout designed the first solar energy motor and operated the first solar powered mechanical steam engine. In 1876 - 1878, William Adams designed the Power Tower steam engine, which is still used today.
In 1883, Charles Fritz invented the first solar cell to convert solar energy into electricity. In 1954, Calvin Fuller, Gerald Pearson and Daryl Chaplin accidentally discovered that silicon is a very efficient electricity conductor. In the 1950s the first satellite using solar energy, the Vanguard I was launched into space.
The use of solar energy is not harmful to the environment because there is no by-production of greenhouse gasses, air or water.
However, some of the materials used for making photovoltaic cells such as toxic chemicals, solvents and alcohols release waste materials that can be harmful. In addition, the large solar power plants can be hazardous to desert eco systems.
The future of solar energy is very bright. Since it is one of the most accessible and easily harnessed renewable natural energy sources, which is safe to use and is environmentally friendly, it has the potential to be one of the primary sources of energy in the world.
Given the high rate of global warming because of accelerated carbon emissions, the increasing dependence and shortage of non-renewable sources of energy like fossil fuels and the looming energy crisis, experts predict that more and more people will turn towards solar energy in the coming years.