Solar & Electric Grid

Majid Mushtaq

St. Cloud State University

Agenda:

Electric Grid Components of Electric Grid Solar Generated Electricity Grid Connected PV System Conclusion

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

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

SOLAR ENERGY

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.

Solar Generated Electricity:i) Photovoltaic Cells (PV)

ii) Concentrating Solar Power (CSP)

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.

Photovoltaic Cells:

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

i) Power Tower:

ii) Parabolic Through:

GRID CONNECTED PV SYSTEM:

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.

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

Grid connected PV Components:

Photovoltaic Cells Inverters Wiring Charge controller Disconnect switch Electrical Meter Total system cost = ~ 8$/watt

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

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

Inverter:

Conclusion:

Cut-down electricity bill Renewable energy source Environment friendly Low or no maintenance cost