Solar energy is the sun's radiant light and heat that is harnessed through a variety of technologies, including solar energy for electricity generation, solar thermal energy for space heating, and solar architecture.
Diffrent Forms of Solar Energy
It is a critical source of renewable energy, and its technologies are broadly classified as passive or active solar, depending on how solar energy is captured, distributed, and converted into solar power. To harness the energy from the sun, active solar techniques such as photovoltaic systems, concentrated solar power, and solar water heating are used. Passive solar techniques include orienting a building toward the Sun, selecting materials with high thermal mass or light-dispersing properties, and designing spaces with natural air circulation.
Solar energy's enormous potential makes it an extremely appealing source of electricity. Carbon Tracker Initiative estimated in 2021 that the land area required to generate all of our energy from solar alone would be 450,000 km2, or roughly the size of Sweden, Morocco, or California (0.3 percent of the Earth's total land area).
The International Energy Agency stated in 2011 that "The development of affordable, self-sustaining, and environmentally friendly solar energy technologies will have enormous long-term benefits. It will increase countries' energy security by relying on an indigenous, inexhaustible, and largely import-independent resource; it will improve sustainability; it will reduce pollution; and it will reduce the cost of mitigating global warming.... These benefits are global in scope."
Average insolation is a possibility. The theoretical area of the small black dots is sufficient to meet the world's total energy consumption of 18 TW entirely through solar energy.
At the upper atmosphere, the Earth receives 174 petawatts (PW) of solar radiation (insolation). Around 30% is reflected back to space, with the remainder being absorbed by clouds, oceans, and land masses. Solar light strikes the Earth's surface primarily in the visible and near-infrared ranges, with a small amount in the near-ultraviolet. The majority of the world's population lives in areas with an annual insolation of 150–300 watts/m2, or 3.5–7.0 kWh/m2.
Solar radiation is absorbed by the Earth's land surface, oceans – which cover approximately 71% of the planet's surface – and atmosphere. Warm air containing evaporation of ocean water rises, resulting in atmospheric circulation, or convection. When air reaches a high altitude with a low temperature, water vapour condenses into clouds, which eventually rain onto the Earth's surface, completing the water cycle. Convection is accelerated by the latent heat of water condensation, resulting in atmospheric phenomena such as wind, cyclones, and anticyclones. The sun's rays are absorbed by the oceans and land masses, maintaining an average surface temperature of 14 °C. Green plants convert solar energy into chemically stored energy through photosynthesis, which results in the production of food, wood, and the biomass from which fossil fuels are derived.
Each year, the Earth's atmosphere, oceans, and land masses absorb approximately 3,850,000 exajoules (EJ) of solar energy. This was more energy consumed in one hour than the entire world consumed in a year in 2002. Photosynthesis converts approximately 3,000 EJ of energy into biomass per year. Solar energy reaching the planet's surface is enormous, about twice as much as will ever be obtained from all of the Earth's non-renewable resources combined, including coal, oil, natural gas, and mined uranium.
The amount of solar energy that humans could use differs from the amount of solar energy present near the planet's surface due to factors such as geography, time variation, cloud cover, and the amount of land available to humans.
Geographical location has an effect on solar energy potential because areas closer to the equator receive more solar radiation. However, by utilising photovoltaics that track the Sun's position, the solar energy potential in areas farther from the equator can be significantly increased. Time variation has an effect on solar energy potential because there is little solar radiation on the Earth's surface during the night for solar panels to absorb. This significantly restricts the amount of energy that solar panels can absorb in a single day. Cloud cover can have an effect on the solar panel's potential because clouds block the Sun's incoming light, reducing the amount of light available to the solar cells.
Additionally, land availability has a significant impact on the amount of solar energy available, as solar panels can only be installed on otherwise undeveloped land that is suitable for solar panels. Solar cells are well-suited for rooftops, as many people have discovered that they can collect energy directly from their homes in this manner. Additionally, solar cells are suitable for areas that are not currently used for commercial purposes and can be used to establish solar plants.
Solar technologies are classified as passive or active based on how they capture, convert, and distribute sunlight, allowing solar energy to be harnessed at various levels throughout the world, primarily based on distance from the equator. While solar energy primarily refers to the practical application of solar radiation, all renewable energies, with the exception of geothermal and tidal energy, derive their energy either directly or indirectly from the Sun.
Active solar techniques convert sunlight into useful outputs via photovoltaics, concentrated solar power, solar thermal collectors, pumps, and fans. Passive solar techniques include the use of materials with favourable thermal properties, the design of spaces that naturally circulate air, and aligning a building's orientation with the Sun. Active solar technologies increase energy supply and are classified as supply side technologies, whereas passive solar technologies reduce the need for alternative energy sources and are classified as demand side technologies.
In 2000, the United Nations Development Programme, the United Nations Department of Economic and Social Affairs, and the World Energy Council published an estimate of the annual amount of solar energy that humans could use, taking into account factors such as insolation, cloud cover, and human-usable land. Solar energy has a global potential of 1,600 to 49,800 exajoules (4.41014 to 1.41016 kWh) per year, according to the estimate.
Production of electricity:
Solar energy is the conversion of renewable energy from sunlight to electricity, either directly or indirectly via photovoltaics (PV) or concentrated solar power. Concentrated solar power systems focus a large area of sunlight into a narrow beam using lenses or mirrors and solar tracking systems. Photovoltaic cells utilise the photovoltaic effect to convert light to an electric current. Companies like Bigwit Energy are installing solar panels on industrial rooftops and ground mounted to help people adopt solar easily.
Initially, photovoltaics were used exclusively as a source of electricity for small and medium-sized applications, ranging from a single solar cell-powered calculator to remote homes powered by an off-grid rooftop PV system. Concentrated solar power plants for commercial use were first developed in the 1980s. Since then, as the cost of solar energy has decreased, grid-connected solar photovoltaic (PV) systems have grown at a nearly exponential rate. Thousands of installations and gigawatt-scale photovoltaic power plants have been built and are currently under construction. Solar photovoltaic (PV) technology has rapidly evolved into an affordable, low-carbon technology.
The International Energy Agency stated in 2021 that solar power would account for approximately 20% of global energy consumption under its "Net Zero by 2050" scenario, making solar the world's largest source of electricity. China has the most solar panels installed. Solar energy generated 3.5 percent of the world's electricity in 2020, up from less than 3% the previous year. In 2020, the unsubsidized levelized cost of electricity for utility-scale solar energy was approximately $36/MWh, and installation cost was approximately a dollar per DC watt.
The Solar Settlement is a project in Freiburg, Germany, that aims to create a sustainable housing community.
Photovoltaic SUDI shade is a self-contained, mobile station in France that uses solar energy to power electric vehicles.
The International Space Station's solar panels
Photovoltaics (PV) is the conversion of light to electricity through the use of semiconducting materials that exhibit the photovoltaic effect, a physical, photochemical, and electrochemical phenomenon. Commercially, the photovoltaic effect is used to generate electricity and as photosensors.
A photovoltaic system generates electricity through the use of solar modules, each of which contains a number of solar cells. Ground-mounted, rooftop, wall-mounted, or floating photovoltaic installations are all possible. The mount can be fixed or track the sun's path across the sky using a solar tracker.
Some hope that photovoltaic technology will eventually generate enough affordable sustainable energy to help mitigate the effects of global warming caused by CO2. Solar photovoltaic energy has distinct advantages as an energy source: once installed, it produces no pollution or greenhouse gas emissions, it is easily scaleable in terms of power requirements, and silicon is abundant in the Earth's crust, although other materials required for PV system manufacture, such as silver, will eventually constrain the technology's growth. Additional significant constraints identified include competition for land use and a labour shortage when submitting funding applications. PV as a primary source requires energy storage systems or global distribution via high-voltage direct current power lines, which adds to the cost, and also has a number of other specific disadvantages, such as unstable power generation and the requirement for power companies to compensate for too much solar power in the supply mix with more reliable conventional power supplies to manage demand peaks and potential undersupply. The manufacturing and installation processes generate pollution and greenhouse gas emissions, and there are no viable recycling systems for the panels once their lifespan of 10 to 30 years has expired.
Photovoltaic systems have been used in specialised applications as stand-alone installations since the 1970s, and grid-connected photovoltaic systems have been used since the 1990s. The first mass-produced photovoltaic modules began in 2000, when German environmentalists and the Eurosolar organisation received government funding for a 10,000-roof programme.
PV's growth as an energy source has been facilitated by falling costs. This is partly due to the Chinese government's massive investment in developing solar production capacity and achieving economies of scale since 2000. The cost of production is largely determined by the price of the critical component polysilicon, and the majority of the world supply is produced in China, particularly in Xinjiang. Apart from subsidies, the low prices of solar panels in the 2010s were made possible by the low cost of coal-fired energy and cheap labour in Xinjiang, as well as advancements in manufacturing technology and efficiency. Increased manufacturing scale and advancements in technology have also increased the efficiency of photovoltaic installations. Solar PV installations in a number of countries have been aided by net metering and financial incentives such as preferential feed-in tariffs for solar-generated electricity. Between 2004 and 2011, panel prices fell by a factor of four. Module prices fell by 90% during the 2010s, but began to rise sharply in 2021.
Global installed photovoltaic (PV) capacity increased to more than 635 gigawatts (GW) in 2019, covering approximately 2% of global electricity demand. PV is the third renewable energy source in terms of global capacity, behind hydro and wind. The International Energy Agency forecasted a 700–880 GW increase between 2019 and 2024. PV has been the cheapest source of electricity in some instances, with a bid for pricing as low as 0.01567 US$/kWh in Qatar in 2020.
Solar concentrating energy
Concentrating Solar Power (CSP) systems focus a large area of sunlight into a narrow beam using lenses or mirrors and tracking systems. The concentrated heat is then used to power a conventional power plant via a heat exchanger. There are numerous concentrating technologies; the most advanced are the parabolic trough, concentrating linear fresnel reflector, Stirling dish, and solar power tower. Numerous techniques are used to track and focus light on the Sun. In each of these systems, concentrated sunlight heats a working fluid, which is then used to generate electricity or store energy. Solar power plant designs must take into account the possibility of a dust storm, hail, or other extreme weather event damaging the fine glass surfaces of solar power plants. Metal grills would allow the majority of sunlight to reach the mirrors and solar panels while also preventing the majority of damage.