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Solar Power Tower

12 October 2012 3 Comments by powersector

In the Sahara desert, with less cloud cover and a better solar angle, one can obtain closer to 83 W/m². The unpopulated area of the Sahara desert is over 9 million km², which if covered with solar panels would provide 750 terawatts total. The Earth’s current energy consumption is around 13.5 TW at any given moment (including oil, gas, coal, nuclear, and hydroelectric power).About one percent of the surface of the Sahara desert would be sufficient to supply the entire worldwide electricity demand from solar thermal power plants. For that reason, many people hope solar thermal power will be implanted in sun-belt countries. In contrast to photovoltaic plants, solar thermal power plants are not based on the photo effect, but generate electricity from the heat produced by sunlight.

The plants will utilize Distributed Power TowerTM (DPT) solar field technology. Distributed Power Tower (DPT) technology is fundamentally simple. DPT solar power plants use mirrors (known as heliostats) to harness the sun much like a camper uses a magnifying glass to start a fire. Thousands of small, flat mirrors reflect the sun’s rays onto a boiler atop the central Tower. Each mirror will provide enough solar energy to power one home. When the concentrated sunlight strikes the boiler’s pipes, it heats the water inside to 550°C - nearly 1000° F - the temperature necessary for the plant to achieve the highest operating efficiency. This very high temperature steam is piped from the boiler to a standard turbine where electricity is generated. The receiver is located on the top of the power tower. Power towers are linked together by pipelines to a central location where electricity is generated and sent to a power grid. From here, transmission lines carry the power to homes and businesses. And nothing is wasted. Each plant would use an air-cooled condenser or “dry cooling,” to minimize water usage in the site’s desert environment. Water consumption would therefore, be mainly to provide water for washing heliostats. No wastewater would be generated by the system, except for a small stream that would be treated and used for landscape irrigation.

. The heliostats are flat mirrors of standard glass with 7.3 m² of surface area. They reflect sunlight onto a receiver located on top of a power tower. Each heliostat is a sophisticated assembly, but all of its components are standard products readily available. The small mirrors utilized in the DPT 550 technology are much simpler to manufacture and less costly to install than the parabolic mirrors used in solar troughs. Like a sunflower, the heliostats follow the sun in two dimensions, enabling them to achieve a much higher efficiency than other solar thermal technologies. Each heliostat is individually installed and controlled, resulting in greater flexibility in site configuration, and requiring much less site preparation.

References

  1. http://www.brightsourceenergy.com/dpt.htm
  2. http://www.unescap.org/esd/energy
  3. http://www.nrel.gov (National Renewable Energy Laboratory).
  4. www.solarenergy.com
  5. Solar Energy Report (PDF)
  6. http://www1.eere.energy.gov/solar/ (U.S. Department of Energy, Solar Energy Technologies Program)
  7. The Energy Blog

3 Comments »

  • cmab said:

    power sector,

    great article. do you think that we can propose or share this information with authorities in pakistan. we should find out a way to provide such information to AEDB (Alternative energy development board of pakistan).

    do you think adding more information like how can one build a small solar panel inhouse serve the purpose?

  • powersector (author) said:

    HI Cmab !
    Thanks for appreciation !
    These are the statistics about desert area in Pakistan .
    1. Area: 2.34 million km2
    2. Solar Intensity: approx 6 kWh/m2/day
    3. Sun Availability: 345-355 days in a year
    these statistics shows that only taking into consideration our solar resources , Pakistan can easily fulfill its electricity needs.soon i will be adding information about installation of solar panels at domestic level .

  • EnergyIdeas said:

    What is the authors name of this artical?

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