Solar energy is the technology used to convert Sun’s energy and make it usable. The Sunrays that fall on solar cells help in releasing the electrons from the atoms and allow the electrons to flow through solar cells thus producing electricity. The solar energy that is released is utilized to replace different kinds of energy systems that make us of fossil fuels. Solar energy thus helps in reducing the release of harmful gases into the atmosphere. The Sun’s rays have enough energy to satisfy worldwide energy needs throughout the year. But this technology produces less than one percent of global energy demand even today.
Solar thermal power plants utilize various techniques to gather the Sun’s energy as a source of heat. Thus generated heat is used to boil water to drive a steam turbine that produces electricity. Solar energy is praised as an unlimited fuel source that is both noise and pollution free. Few new generation of Solar thermal plants types include:
The Parabolic Trough uses rows of curved mirrors that reflect heat onto a tube filled with fluid. The fluid runs through the receiver and becomes very hot, boils water to make steam that will twirl a turbine. The fluid holding the heat is carried to a heat engine where one-third of the heat is transformed in to electricity. Common fluids are molten salt, synthetic oil and pressurized steam. Few power generators are also constructing trough systems to supplement gas plants. Surplus heat can be stored in molten salt to run turbines in the absence of Sunlight.
A tower is placed in the center of the heliostat field and water is placed in a tower. The modular nature of the heliostats or mirrors makes building easier. Tower and trough compete against each other but tower can operate at a higher temperature. So a tower is preferred in the long run. Another advantage for heliostats is the field mirrors that can lean in two directions.
A dish Stirling energy system uses a large and reflective dish. It centers all the Sunlight to a single point above the dish where a receiver collects the heat and converts it into a useful form. The dish is united with a Stirling engine and sometimes a steam engine. These generate rotational kinetic energy that can be transformed into electricity by using a power producer. A dish system can attain much higher temperatures due to the high concentration of light that results in better conversion to electricity.
A Fresnel reflector power plant uses narrow, shallow-curvature mirrors to center light to one or more receivers located above the mirrors. Above the receiver a small parabolic mirror is attached for additional focusing of the light. This system offers lower overall costs by distributing a receiver between numerous mirrors. The receiver is stationary and so fluid combinations are not required. The mirrors do not need to support the receiver so they are structurally simpler. When appropriate strategies are used this can allow a thick packing of mirrors on obtainable land area.
These are some of the new generation of solar thermal plants that can be utilized to produce power naturally without having any adverse effects on the environment.