Solar and Electric Grid: A brief presentation.

1. Majid Mushtaq
St. Cloud State University

2. Agenda:
Electric Grid
 Components of Electric Grid
 Solar Generated Electricity
 Grid Connected PV System
 Conclusion


3. Electric Grid:
Interconnected network for delivering
electricity from suppliers to consumers
 Consists of generating station,
transmission lines, distribution lines and
substation
 Maintains instantaneous balance
between supply and demand


5. 3 components of Electric Grid:
Generation: creating electricity
 Transmission: Moving it from bulk
generators to distribution centers
 Distribution: bringing it from
substations to homes and industries


7. Solar Energy Potential:
 The
amount of solar energy that
reaches the Earth’s surface every
hour is greater than humankind’s total
demand for energy in one year
 As of February 2006, Photovoltaic
technology accounted for less than
1% of worldwide electricity
generation.

8. Photovoltaic Cells (PV)
ii) Concentrating Solar Power (CSP)
i)

9. Photovoltaic Cells:
Photovoltaic cells convert light energy to
electric current by Photoelectric effect
 Produce direct current which fluctuates
with light intensity
 For practical use it should be converted
to a certain fix voltage or AC current
through the use of Inverters.


10. Photovoltaic Cells:

11. Concentrating Solar Power:
Requires direct sunlight
 use lenses or mirrors to focus large area
of sunlight into smaller beam
 Not very effective in cloudy conditions
 Two approaches
i) Power Tower
ii) Parabolic Through


12. i) Power Tower:

14. ii) Parabolic Through:

17. When a solar energy system is connected to
the grid it is capable of sending electricity to
the grid that can be used at a later time
when the system is not producing electricity.
 In the most simplest terms pulling energy
from the grid when needed and supplying
energy to the grid when energy is not being
used at the solar site.


19. Advantages:
Eliminates the need of batteries
 Reduces cost and maintenance

Highly efficient use of the system
 Long life span


Ensures a constant supply of electricity

20. Grid connected PV
Components:
Photovoltaic Cells
 Inverters
 Wiring
 Charge controller
 Disconnect switch
 Electrical Meter
 Total system cost = ~ 8$/watt


23. Net metering:
Electricity delivered to the grid can be
compensated in several ways
 "Net metering", is where the entity that owns the
renewable energy power source receives
compensation from the utility for its net outflow of
power.
 For example, if during a given month a power
system feeds 500 kilowatt-hours into the grid and
uses 100 kilowatt-hours from the grid, it would
receive compensation for 400 kilowatt-hours


24. Grid Tie Inverter:
Special type of power inverter converts
DC to AC
 And feeds it into existing electrical grid
 During period of overproduction, power
is routed into the grid
 During insufficient power production it
purchases power from utility company


25. Inverter:

26. Conclusion:
Cut-down electricity bill
 Renewable energy source
 Environment friendly
 Low or no maintenance cost
