Page Selected:  Solar Tower Technology   

Project:  Solar Tower Technology

Air is heated by solar radiation under a low circular glass roof open at the periphery; this and the natural ground below it form a hot air collector. In the middle of the roof is a vertical tower with large air inlets at its base. The joint between the roof and the tower base is airtight. As hot air is lighter than cold air it rises up through the chimney. Suction from the tower then draws in more hot air from the collector, and cold air flows in from the outer perimeter. The solar radiation is responsible for causing a constant up-draught in the tower. The energy created through this process is converted into mechanical energy by the rising air passing through the pressure-staged wind turbines at the base of the tower, and into electrical energy by conventional generators. 

A single tower with a suitably large glazed roof area and a high enough chimney can be designed to generate 100-200 MW. It is encouraging to know based on the solar chimney power plant’s ability to generate electricity; even a small number of solar towers could be introduced to replace a large nuclear power station, currently the dominant alternate power source. The proposed Solar Tower Power plants are being built to a size of 200 MW.  A power plant of this size will power a US city with a population of about 120,000 people. In a developing country such as India, it will supply enough energy to supply at least 500,000 people. A 200 MW power station is the same size as most conventional power production facilities.

The Solar Tower operates simply and has a number of advantages:

• Solar towers generate electricity without any negative environmental consequences. 

• The collector can use both direct and diffused solar radiation; this is in contrast to other major large-scale solar-thermal power plants that can only use direct radiation. This is crucial for tropical countries where the sky is frequently overcast. 

• The collector provides storage for natural energy, at no additional cost. The ground under the glass roof absorbs some of the radiated energy during the day and releases it into the collector at night. This enables solar towers to produce a significant amount of electricity throughout the night.  Advancements have been made allowing 24-hour power production. 

• Solar Towers are particularly reliable and not liable to break down, in comparison with other solar generation plants. Turbines, transmissions and generator are the plant’s only moving parts. This simple and robust structure guarantees an operation that needs little maintenance, and of course no combustible fuel. 

Unlike conventional power stations (and also other solar-thermal power station types), solar towers do not need cooling water. This is a key advantage in the many sunny countries that already have major problems with insufficient drinking water.

The building materials needed for solar towers, mainly concrete and glass, are available everywhere in sufficient quantities. In fact, with the energy taken from the solar tower itself and the stone and sand available in the desert, building materials can be produced on site.

Solar towers can be built now, even in less industrially developed countries. The industry level already available in most countries is entirely adequate for their requirements. Investment in a high-tech manufacturing plant is therefore not needed.

Even in poor countries it is possible to build a large plant without high foreign currency expenditure as their own resources and work-force can be utilized; this creates large numbers of jobs and dramatically reduces investment requirement and the cost of generating electricity.

Solar Towers can not convert the entire proportion of solar heat collected into electricity, but manages to compensate for this disadvantage by their cheap, robust construction and low maintenance costs. Solar Towers need large collector areas. For economically viable operation of solar electricity production plants it is essential they operate in regions with high solar radiation, this is not a fundamental disadvantage, as such regions usually have enormous deserts and unutilized areas. It should be remembered that care should still be taken in regard to the deserts as they are critical to the survival of the planet and hence must be protected.

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