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Energy and the Environment

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  1. Introduction
  2. Transport Fuels
    5 Topics
  3. Energy Sources: Fossil Fuels
    8 Topics
  4. Energy Sources: Renewables
    10 Topics
  5. Electricity
    10 Topics
  6. Energy Sources: Nuclear
    6 Topics
  7. Demand Response
    6 Topics
  8. Energy/Emissions Policy
    15 Topics
  9. Energy Economics
    2 Topics
    1 Quiz
Lesson 4, Topic 1
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Solar (PV & thermal)

Abdulaziz July 15, 2020
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Photovoltaic Cells

How do PV cells work ?

  • When light energy strikes the solar cell , electrons are knocked loose from the atoms in the semiconductor material.
  • If electrical conductors are attached to the positive and negative sides, forming an electrical circuit, the electrons can be captured in the form of an electric current that is, electricity

P-N Junction Solar Cells

TheSolarSpark Courtesy

Silicon Structure

  • Crystal of pure silicon (lattice) ‘doped’ with impurity
    • element with more e in outer shell than Si means e free to move (negatively charged Si – n-type)
    • element with less e in outer shell than Si means overall shortage of e (positively charged Si – p-type)
  • n-type & p-type Si in contact with each other
  • e move across from n to p via junction
  • light energy pushes e across junction and, if an electrical circuit is made between the two silicon types, e will flow through it
Photovoltaic panel
Photovoltaic panel

Solar Power – Different Technology Available

  • Solar thermal systems
    • Non concentrating (passive)
    • Concentrating (active)
      • Troughs, dishes, linear Fresnel, towers & heliostat
    • Storing Solar thermal
  • Photovoltaic cell types
    • Monocrystalline
    • Polycrystalline
    • Amorphous

Passive (non concentrating) Solar Thermal

  • Domestic water heating
  • Pool heaters
  • Space heating
  • Water processes for industrial heating
  • Agricultural drying
Solar Heating and Cooling Technologies | Renewable Heating and ...

Concentrating Solar Thermal

  • absorbs & collects solar radiation
  • mirrors reflect & concentrate sunlight
  • receivers collect solar energy convert it to heat energy
    • Heat → Steam → Turbine → Generator → Electricity
  • Parabolic trough
    • ~ 80 MW
  • Solar dish / engine
    • ~ (325 MW)

Parabolic Trough Solar Collectors

Source: U.S. Department of Energy.

Linear Fresnal Reflector (LFR)

  • Fresnel: flat lens made of a number of concentric rings, to reduce spherical aberration.
    • ~ 2 MW
Source: U.S. Department of Energy.

Tower & heliostat

  • in development phase
    • ~ 200 MW

Concentrating Solar Thermal

Source: Abengoa Solar – Innovative technology solutions for sustainability, A New Generation of Parabolic Trough Technology, SunShot CSP Program Review 2013, Phoenix, April 2013 *

Hybrid Solar Thermal Power Plants

Source: Courtesy of SolEngCo GmbH – Georg Brakmann.

Other Solar Thermal Technologies

Schematic of a solar chimney.
Breeze, P. (2019). Chapter 13 – Solar Power. In P. B. T.-P. G. T. (Third E. Breeze (Ed.) (pp. 293–321). Newnes.
Schematic of a solar pond power plant.
Breeze, P. (2019). Chapter 13 – Solar Power. In P. B. T.-P. G. T. (Third E. Breeze (Ed.) (pp. 293–321). Newnes.