The term solar power commonly conjures images of blue or black rectangular panels placed on the roof of a house, providing cost and pollution free electricity to the lucky homeowners beneath. But these panels are not the only way the sun's energy can be turned into electrical power. One major way of creating commercial scale electricity is with Concentrated Thermal technology. Power stations using this are in operation and these work on a scale similar to coal fired power stations. How does this technology work?
Whereas domestic solar panels convert sunlight directly into electricity, Concentrated Thermal solar works with the heat of the sun's rays. As children most of us will have used a magnifying glass to burn bits of wood, cardboard and the odd unfortunate ant. When we concentrate of the sun's rays through the magnifying glass lens it is acting as a heliostat. Concentrated Thermal works in a similar way but it reflects the heat from mirrors rather than condensing it through a lens.
If a mirror is made into an arc shape called a parabola, it will reflect all the light that hits it onto a single point, assuming that it is facing directly at the sun. The amount of light and therefore heat at this point is determined by the size of the mirror. A large area of mirror can produce extremely high temperatures. There are commercially available dish-shaped solar cookers that are used for boiling water which operate on this principle.
In order to use this technology to produce electricity, it is necessary to place a tube containing synthetic oil in the focal point of the mirror. This oil can be heated to many hundreds of degrees. This oil is then pumped to a turbine where it is used to heat water to make steam. This steam then turns the turbine to generate electricity in the same way that a coal fired power station does.
The more mirror surface there is the better the system works, as more heat is harvested. Power stations using Concentrated Thermal technology consist of seemingly endless rows of these parabolic mirrors that move with the sun, maximizing energy collection throughout the day. These power stations also have salt tanks that can be used to store excess energy so the power plant can keep generating electricity at night. The energy is stored by melting the salt and then using the heat it gives off as it cools.
This method of generating electricity works only where there is enough sunlight. It is cheap, reliable and safe and on a large enough scale it is capable of providing base load domestic electricity. The only pollution associated with such a power station is from the initial building. Aside from that it provides endless clean energy at a minimal cost.
Whereas domestic solar panels convert sunlight directly into electricity, Concentrated Thermal solar works with the heat of the sun's rays. As children most of us will have used a magnifying glass to burn bits of wood, cardboard and the odd unfortunate ant. When we concentrate of the sun's rays through the magnifying glass lens it is acting as a heliostat. Concentrated Thermal works in a similar way but it reflects the heat from mirrors rather than condensing it through a lens.
If a mirror is made into an arc shape called a parabola, it will reflect all the light that hits it onto a single point, assuming that it is facing directly at the sun. The amount of light and therefore heat at this point is determined by the size of the mirror. A large area of mirror can produce extremely high temperatures. There are commercially available dish-shaped solar cookers that are used for boiling water which operate on this principle.
In order to use this technology to produce electricity, it is necessary to place a tube containing synthetic oil in the focal point of the mirror. This oil can be heated to many hundreds of degrees. This oil is then pumped to a turbine where it is used to heat water to make steam. This steam then turns the turbine to generate electricity in the same way that a coal fired power station does.
The more mirror surface there is the better the system works, as more heat is harvested. Power stations using Concentrated Thermal technology consist of seemingly endless rows of these parabolic mirrors that move with the sun, maximizing energy collection throughout the day. These power stations also have salt tanks that can be used to store excess energy so the power plant can keep generating electricity at night. The energy is stored by melting the salt and then using the heat it gives off as it cools.
This method of generating electricity works only where there is enough sunlight. It is cheap, reliable and safe and on a large enough scale it is capable of providing base load domestic electricity. The only pollution associated with such a power station is from the initial building. Aside from that it provides endless clean energy at a minimal cost.
About the Author:
Find out more about the production and uses of solar power at Roger Vanderlely's website. There are also free solar energy education experiments to help your child understand more about the energy of the sun.
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