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					Industrial High Temperature
Solar Thermal
Power Plants


                Joshua E. Richardson
Industrial High Temperature Solar Thermal Power
Plants are systems for industrial scale use only that
utilize solar heat energy to power a turbine in order to
produce electricity.
                 Main Goals
• To successfully provide a fuel that is:
  – Clean
  – Efficient
  – Cost-effective
• Energy used specifically for industry-scale
              Overall Potential
• By using only 1% of the earth’s deserts, more clean
  solar electric power could be produced than is
  currently produced worldwide with fossil fuels.
• It is theoretically possible that over 90 percent of the
  nation’s electricity and most of the transportation
  sector’s energy needs, could be supplied by solar
  thermal technology within the next 50 years.
• Estimated that by 2010, systems will exceed
  5,000 MW…enough to serve needs of 7 million
  people and save the equivalent of 46 million barrels
  of oil each year.
           How does it work?
• Five types with different models.
• All operate somewhat alike:
  – Use lenses and reflectors to concentrate solar
  – Heat drives thermal power plant.

        What happens at night?
• Power is stored during the daytime in molten salt at
  approximately 1050°F
• Salt sometimes used to heat graphite which would be
  used as a heat storage medium night-time
  operations are possible!
• Storage of heat from solar power plants can allow
  solar power plants to operate around the clock
   – unique because they can generate power when it is
     needed…day or night…rain or shine
•   Solar “Power Towers”
•   Parabolic trough
•   Solar Dish/Engine Systems
•   CSP plants
•   Fresnel Reflectors

 Comparison of Major Solar Thermal Technologies
 (tower, dish, trough)

                                    Power                           Parabolic                           Parabolic
                                    Tower                             Dish                               Trough
Applications             Grid-connected                     Stand-alone small                  Grid-connected
                         electric plants;                   power systems; grid                electric plants;
                         process heat for                   support                            process heat for
                         industrial use.                                                       industrial use.
Advantages               Dispatchable base                  Dispatchable                       Dispatchable
                         load electricity; high             electricity, high                  peaking electricity;
                         conversion                         conversion                         commercially
                         efficiencies; energy               efficiencies;                      available with 4,500
                         storage; hybrid                    modularity; hybrid                 Gwh operating
                         (solar/fossil)                     (solar/fossil)                     experience; hybrid
                         operation.                         operation.                         (solar/fossil)

               [Source: Status Report on Solar Thermal Power Plants. Pilkington Solar International GmbH: Cologne, Germany,1996.]
                 “Power Towers”
• The first large-scale solar energy project in the U.S.
   – 1982
   – DOE and individual corporations
• Solar plant with a field of computerized mirrors
  called heliostats that follow the sun.
• Heliostats reflect rays towards
  a central tower where heat is
  used to produce steam.
• Steam turns a turbine like
  in more traditional plants.

        Power Towers, cont’d
• Power Tower 1- original trial.
  – Success!
• Power Tower 2- 10MW second generation
  – 1926 heliostats
  – 300 ft. tower
  – Power for 10,000 homes
• Discussion about a 30 to 100 MW tower in
            Parabolic Trough
• Made of long rows of concentrating mirrors
• Only curved in one direction
• Track the sun from East to West with surface
  that focuses sun’s energy
• Heat transfer fluid runs through pipe that is at
  the focus of the troughs
• Heat is transferred to working fluid (usually
  water) and used to power or drive turbine
                               Parabolic Trough

An Acciona solar thermal power plant, located south of Las Vegas.

 Parabolic Dish/Engine Systems
• Still under development
• Consists of parabolic shaped concentrators that
  track sun in two-axis
• Cycle heat engine mounted on receiver
  generates electricity, or
• sunlight heats fluid that
  is transmitted to a
  central engine

   Political/Economic Obstacles
• Currently not economical
  – high cost of building facilities needed
  – currently can only lengthen the amount of time you
    have energy by a few hours
  – would require more high voltage DC lines to carry
    the electricity from the southwestern U.S. to the
    rest of the country
• Funding will be needed to bring solar thermal
  electric into large scale development
Political/Economic Opportunities
• Can create 2 and ½ times as many skilled high
  paying jobs as conventional power plants that
  use fossil fuels
• Moderate net energy
• Moderate environmental impact
• Costs reduced with natural gas turbine backup
       Technological Obstacles
• Needs back up or storage system
• Storage: the solar thermal plans would need
  just 16 hours of storage to continuously
  generate electricity
• Low efficiency
  – increasing efficiency by 20-30% could
    significantly reduce the cost of electricity
   Technological Breakthroughs
• Future solar collectors will be mass-produced
  – lower cost flat mirrors, rather than curved troughs
  – and sit low to the ground reducing wind loads
• Fast construction (1-2 years)
             Land Use Issues
• Takes lots of area requiring high land use
• Works best in desert or other areas with lots of
Negative Environmental Impacts
• May disturb desert areas
• Could potentially endanger wildlife
• Take up at least nine square miles of space
 Positive Environmental Impacts
• No CO2 emissions
  – reduces air pollution
• Less use of fossil fuel
               Costs of Use
• 15 – 20 cents per kilowatt-hour (kwh)
  – Comparison to wind…8 cents per kwh
• Costs to produce facility
  – One-half (50%) the cost of solar power tower is
    associated with mirrors that focus light on the
  – Less than one-third (33%) is associated with
    power cycle and heat storage
          Additional Benefits
• The peak demand period - during the hottest
  part of the day, when air conditioners are
  running in the office and home - coincides
  with the period of time when the solar thermal
  power plant is at peak production
• Steam is emitted rather than greenhouse gases
• Solar thermal energy could lead the United
  States into a renewable future.
• Cost reduction of producing solar thermal
  energy could make this the most viable type
  of available energy.
•   http://www.schott.com/newsfiles/20061109160336_SCHOTT_Memorandum_E.pdf
•   http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO000129000002000
•   http://www.renewables-made-in-germany.com/en/solar-thermal-power-plants/
•   http://www.worldofrenewables.com/page.php?pageid=32
•   http://www.nrel.gov/csp/pdfs/35060.pdf
•   http://www.nytimes.com/2008/03/06/business/06solar.html?_r=1&em&ex=1205038800&en=2d73
•   http://www.futurepundit.com/archives/005052.html
•   http://www.news.com/Shrinking-the-cost-for-solar-power/2100-11392_3-6182947.html
•   http://peakenergy.blogspot.com/2008/03/solar-thermal-power-could-supply-most.html
•   http://media.cleantech.com/2570/ausra-and-solar-thermal-electricity
•   http://www.chiefengineer.org/content/content_display.cfm/seqnumber_content/3070.htm
•   http://www.sciam.com/article.cfm?id=a-solar-grand-plan&page=1
•   Living in the Environment (textbook)

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