Solar energy refers to energy produced by the sun in the form of heat and light. This energy can be harvested and used or converted into electrical or mechanical energy. The most common types of technology used to harness solar energy today include photovoltaics, artificial photosynthesis, solar heating and solar thermal energy. The development of solar harvesting technology, over the last few years, has brought about advancement in the application of solar energy. Its flexibility and abundance make solar energy immensely attractive as a modern means of power generation. It can be used to power industries and cities using large solar plants while providing electricity to rural areas off the grid.
Solar harnessing technology can be broadly categorized into active or passive. This categorization is based on the use of light and heat energy from the sun. Active solar techniques include those that actively harness, and distribute or convert that energy into other forms of energy. Some active solar technologies are photovoltaic systems, solar water heating and concentrated solar power. On the other hand, passive solar techniques include those that use light and heat from the sun directly. These techniques include building orientation and use of materials with favorable thermal mass and light-dispersing properties. This is usually done to maintain proper ventilation and temperature throughout the building.
In 2012, the amount of the sun’s energy absorbed by Earth’s atmosphere, water bodies and masses in an hour was more than the amount of energy the world used in one year. Active solar technology is basically of two types, those that harness solar heat – solar thermal technology and those that harness and transform light energy – photovoltaic solar technology.
Photovoltaic solar technology
This technology converts light energy into electrical energy, known as the photovoltaic effect. This effect was discovered by Edmond Becquerel a French Physicist. The light hitting the surface of the solar panels is converted into electrical energy by a semiconductor, like silicon. The electrical current produced is direct current, which is converted into an alternating current using an inverter. This technology can either be used to harness energy to power electrical devices in homes or in concentrated solar power plants. These solar power plants cover acres of land and produce electricity on a large scale. The electricity produced is fed into the main power grids.
Advancement in technology brought about a slight fall in the prices and an increase in the reliability and efficiency of these installations.
Solar thermal technology
This technology is used to capture the sun’s heat, which is used directly or converted into mechanical energy. This technology is used in homes to provide warm ventilation and solar water heaters, and in industries to run machinery or converted again from mechanical energy to electrical energy.
Low-temperature solar thermal power applications include devices that work under 100°C. These applications of thermal power can be directly used for commercial, residential and industrial purposes. The heat from the sun is harnessed and transferred to a liquid; this liquid transports the thermal energy to places that require heating.
Concentrated Solar power plants are vast ground-mounted arrays used to generate electricity, using heat from the sun. This technology uses a similar process used by nuclear plants to convert heat into mechanical energy and further into electricity. The heat from the sun is concentrated and intensified using mirror arrays. These arrays convert solar radiation into very high temperature, which is used in generating mechanical energy.
Harvesting and using solar generated electricity as a supplementary source of power, apart from other uses, has increased in importance over the last few years. This is a major move towards a cleaner, greener planet, sustainable with clean, inexhaustible energy. Its applications are increasing from powering houses to a range of other uses like vehicles that run solely on solar energy. Solar energy is the way of the future for several obvious reasons, and a means to reduce our carbon footprint by a significant amount.