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Applications

SkyTrough  parabolic trough concentrating solar collectors capture and concentrate solar radiation to produce thermal energy, usually as steam, for use in large power plants for generating electricity as a clean, renewable, and affordable alternative to burning  fossil fuels, such as coal and natural gas to generate the power.

SkyTrough systems are also ideally suited for delivering heat or steam to industrial, mining and manufacturing processes as well as waste-water treatment and desalination. SkyTrough can also be used to heat water for large commercial or institutional facilities such as prisons and hospitals which require large volumes of hot water.

STANDALONE PLANTS

For utility-grade electricity generation, SkyTrough systems can be configured in “stand-alone” solar power plants which are designed and constructed to primarily use solar radiation for generating power with back up capability provided by another fuel, typically natural gas. The Solar Electric Generating Systems (SEGS) plants in California’s Mojave desert – a 354 MWe cluster of nine parabolic trough plants  - which include the first commercial deployment of SkyTrough collectors (at the Sunray Energy Plant, formerly SEGS II) - are a prominent and pioneering example of this configuration.  

Integrated Solar Combined Cycle (ISCC)


Solar generated steam, augmented by hot exhaust from the gas turbine, drives a steam turbine.

SkyTrough and the steam it produces match up particularly well with certain natural gas combined cycle power plants; a combination referred to as integrated solar combined cycle or  “ISCC”. When a host plant uses solar generated steam to displace natural gas fired steam, it saves on fuel costs and cuts emissions of CO2  and other harmful pollutants. Solar fields can be retrofitted to existing combined cycle facilities, or planned as part of new projects.

The ISCC application is able to produce low-cost solar electricity because existing infrastructure is used in a highly efficient way.  A combined cycle plant with duct burners will have capacity in its steam turbine to accommodate the steam produced with the duct burners operating.  In an ISCC system, the plant can accept solar-generated steam when it is available but also run its duct burners to provide firm peaking energy in the absence of available solar-generated steam.

  • More power is produced than with gas alone.
  • Many options for configuration.
  • Solar fraction can be as much as 20%.
  • Solar heat can be used between 400 C and 550 C.

OTHER SOLAR HYBRID APPLICATIONS

SkyTrough technology can also produce and deliver heat or steam to other types of thermal power plants, including those powered by coal, natural gas (boiler), biomass or geothermal.

Advantages of solar thermal power integration

  • Cost of solar generated electricity is typically lower than for stand-alone CSP plants
  • Plant efficiency is typically higher than for stand-alone CSP
  • No daily start-up and shut-down of turbine
  • Installed cost of solar is ~50% of equivalent CSP stand-alone plant
  • Minimal additional plant staff, lower than CSP stand alone
  • No new electrical interconnect
  • Limited additional permitting required

Integrated Solar and Coal (ISC)



Solar generated steam supplants burning of coal to power steam turbine OR solar energy is used to preheat feedwater to steam generator.

  • Less coal is burned to generate same power.
  • Solar fraction can be as much as 20%.
  • Solar heat can be used between 400 C and 550 C.


Geothermal Solar Hybrid



Solar heat is used to boost temperature of geothermal brine OR solar generated vapor augments power to turbine.

  • Diminishing geothermal resource can be boosted, preserving investment in turbine and balance of plant.
  • Solar fraction can be as much as 50%.
  • Solar heat can be used between 140 C and 300 C.


Biomass Solar Hybrid



Gasification - Solar steam augments thermal power from biomass gas boiler to drive a steam turbine. Direct Combustion - Solar steam augments thermal power from biomass furnace to drive a steam turbine.

  • Biomass can be used to “firm” solar power, effectively replacing thermal storage in function.
  • Solar fraction can be as much as 80%.
  • Solar heat can be used between 140 C and 550 C.
  • Plant must be located within 20 miles of biomass source, because fuel is low density and expensive to transport (unless pelletized).


Combined Heat and Power (CHP)

  • In any plant that converts thermal power to electricity, there is an opportunity to capture the heat rejected from the power cycle when there is a use for the heat – such as district or process heating.  CHP can boost the total thermal utilization to over 98%.

SOLAR DESALINATION

Solar heat pairs perfectly with thermal desalination systems including multi-effect and multi-stage flash.
  • High solar radiation where water is scarce.
  • Economical clean water production.
  • Minimal footprint.
  • Potential for cogeneration of water and electricity.