SOLAR ENEGY

Submitted by-

DINESH SHARMA

Roll no.-100104047 B.Tech (EEE)

Sharda University

CONTENTS Important Facts on solar Introduction Working Solar Electric Power Plants Direct Conversion into electricity Advantages Disadvantages Efficiency References

Fast Facts on Solar• The sunlight that reaches the earth is about

200,000 times the total electrical energy generated by humans everyday!

• The first working solar cell was invented by Charles Fritts in 1883 and operated at 1% efficiency.

• The word photovoltaic, the proper name for solar cell, comes from the Greek word for light, which is combined with the name Volta, the last name of the scientist after whom the measurement unit volt is named. All together the word photovoltaic means light electrical or electricity from light.

• Every minute, enough solar energy reaches the Earth to meet global energy demands for a year.

• Originates with the thermonuclear fusion reactions occurring in the sun.

What is Solar Energy?

How much solar energy?

The surface receives about 47% of the total solar energy that reaches the Earth. Only this amount is usable.

How It Works

• Solar energy is harnessed and used through a process using photovoltaic cells, also known as solar cells. These cells or panels are usually made up of two types of silicon.

• Sunlight is made up of little units of energy called photons.

• The solar cell is made up of negative and positive layers, which create an electrical field.

• When the photons hit the surface of the solar cell, the electrons inside the energy from the sun are freed, pass to the bottom of the cell, and flow through to whatever requires power. This flow of electrons is what we know as electricity.

Solar Electric Power Plants

• Efficiency is far lass than the 77% of solar spectrum with usable wavelengths.

• 43% of photon energy is used to warm the crystal.

• Efficiency drops as temperature increases (from 24% at 0°C to 14% at 100°C.)

• Light is reflected off the front face and internal electrical resistance are other factors.

• Overall, the efficiency is about 10-14%.

• Harness solar power to generate electricity

• Main types:– Solar thermal energy

• Has mirrored surface that reflects sunlight to heat up liquid to make steam to generate electricity

– Photovoltaic• Uses photovoltaic cells

that absorb direct sunlight (as discussed previously)

Array of mirrored solar collectors at

FPL Energy site

Direct Conversion into Electricity

• Efficiency is far lass than the 77% of solar spectrum with usable wavelengths.

• 43% of photon energy is used to warm the crystal.

• Efficiency drops as temperature increases (from 24% at 0°C to 14% at 100°C.)

• Light is reflected off the front face and internal electrical resistance are other factors.

• Overall, the efficiency is about 10-14%.

• Photovoltaic cells are capable of directly converting sunlight into electricity.

• A simple wafer of silicon with wires attached to the layers. Current is produced based on types of silicon (n- and p-types) used for the layers. Each cell=0.5 volts.

• Battery needed as storage• No moving partsdo no wear

out, but because they are exposed to the weather, their lifespan is about 20 years.

Advantages1. Non polluting: no noise, no harmful or unpleasant

emissions or smells. 2. Very reliable: most solar panels have a 25 year

warranty and even a longer life expectancy (the theory is they could last 100 to 125 years).

3. Although we cannot utilize the power of the sun at night or cloudy days, we can count on the sun being there the next day, ready to give us more energy and light.

4. Solar modules over their lifetime produce more power per gram of material than nuclear power but without the problem of large volumes of environmentally hazardous material.

5. Solar panels produce more power within 5 years than the power consumed in their production.

6. Solar Power is a renewable energy source. It is a resource that cannot be used up by us using it.

7. Although solar panels may be expensive to buy, you will save money and our environment in the long run.

Disadvantages Cost of electricity from coal-burning

plants is anywhere b/w 8-20 cents/kWh, while photovoltaic power generation is anywhere b/w $0.50-1/kWh.

Does not reflect the true costs of burning coal and its emissions to the nonpolluting method of the latter.

Underlying problem is weighing efficiency against cost. Crystalline silicon-more efficient,

more expensive to manufacture Amorphous silicon-half as efficient,

less expensive to produce.

Efficiency

• Efficiency is far lass than the 77% of solar spectrum with usable wavelengths.

• 43% of photon energy is used to warm the crystal.

• Efficiency drops as temperature increases (from 24% at 0°C to 14% at 100°C.)

• Light is reflected off the front face and internal electrical resistance are other factors.

• Overall, the efficiency is about 10-14%.

Efficiency is far lass than the 77% of solar spectrum with usable wavelengths.

43% of photon energy is used to warm the crystal.

Efficiency drops as temperature increases (from 24% at 0°C to 14% at 100°C.)

Light is reflected off the front face and internal electrical resistance are other factors.

Overall, the efficiency is about 10-14%.

The End