An Overview of Solar Energy

Overview of Solar Energy
Solar energy, a term interchangeably used with solar power is simply energy from the sun. It is the energy which is radiated through the electromagnetic system from the Sun and includes energy produced in the form of heat and electricity by the direct action of isolation by man-made heat collecting devices. Not only is solar energy renewable, but it is also an environmentally friendly form of power. This is because it does not produce carbon dioxide gas in the way fossil fuels do when they are burned. This, scientists believe, is the main cause of global warming.

Benefits of Solar Energy
The main advantages of solar energy are the following:
The resource is large and renewable (can never be depleted through human consumption)Solar energy is more evenly distributed across the globe than fossil fuel stocks, providing greater energy independence and security benefits to nations.Virtually no greenhouse gas emissions are produced by the solar fuel cycle thus making it a climate-friendly technology.Solar technologies are well suited to distributed generation applications (energy production situated at or close to the source of energy demand), which can provide benefits through greater electricity system reliability and lower transmission and distribution losses.Solar energy attracts widespread public acceptance as an energy supply option, although the technology is still at an early stage of deployment.

Science behind Solar Energy-Harvesting, Conversion etc
Solar technologies can be broken down into three principal categories: Solar Thermal, where the heat energy is employed directly for end-use applications (e.g. solar hot water systems, solar passive buildings, and commercial and industrial heat); electricity generated by Photovoltaic cells (PV), which convert sunlight directly to electricity; or Concentrating Solar Power (CSP) systems, which heat water or other fluids to high temperatures suitable for driving standard steam turbines. Each of these solar technologies has considerable long-term potential to supply energy and reduce green house gas emissions.

Solar Thermal Systems
Solar thermal technologies can directly displace other energy sources, notably gas and electricity, used for water and space heating. They can also be used to provide low-grade heat for industrial and commercial agricultural processes. Thermal applications presently account for most of the solar energy contribution to a global energy supply and, at least for the next 10-20 years, are expected to remain the principal means by which solar power can contribute to reducing emissions.

Photovoltaic (PV) Cells
Photovoltaic (solar) cells are the building blocks of solar electric systems. They are made from thin slices of silicon, a plentiful natural resource that is also a major component in computers. Since one cell produces about one or two watts of energy, they are joined together to make modules. PV modules, which have no moving parts, can last from twenty to thirty years. When photons (components of sunlight) strike a solar cell, some are reflected, some pass through while the rest are absorbed by the cell. Only the ones that are absorbed can provide the energy to generate electricity.

When a cell absorbs enough sunlight, the photons release electrons, atomic particles with negative charges. The electrons move to the surfaces of the cells thereby creating an imbalance between the front and back surfaces in a manner similar to the positive and negative ends of a battery. When the two surfaces of the cell are connected by an external piece, electricity flows. This phenomenon, called the photovoltaic effect, is what makes solar electric power.

Concentrating Solar Power (CSP) Systems
This technology uses mirrors to concentrate sunlight, which in turn heats fluid (usually synthetic oil). The fluid is then passed through a heat exchanger to generate steam, which drives a steam turbine to generate electricity. Further, this system has the ability to generate power when the sun is not shining due to its integrated storage components.

Technological progress over the past few decades has been rapid, and the medium-to long-term prospects for solar energy have improved significantly. Overall, solar power is likely to make a relatively small, but increasingly important contribution to emissions reduction up to 2050. In the longer term, beyond 2050, solar energy is destined to become a much more important component of the global energy supply mix for households and businesses.

overview of solar energy

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