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BEFORE WE BEGIN...

PHOTOVOLTAICS

To Help Remember:
Photo: Light
Voltaic: Electricity

How Does It Work?

Sunlight is made from tiny packets of energy called photons.

The photons hit the Solar panels, which are made up of many solar cells.

Electrons inside the solar cells jump back and forth when the photons hit the solar panel.

The electrons create an electric current, and is multiplied by the number of cells in each panel.

ORIGINS AND DISCOVERY

7th Century B.C.
People started using the sun by concentrating its heat and light with glass and mirrors to light fires.

1767
A Swiss scientist Horace de Saussure was credited with building the first solar collector.

1839
French physicist Edmond Becquerel discovered photovoltaics in 1839

1955
Western Electric began to sell commercial licenses for silicon photovoltaic technologies

1964
NASA launches the first Nimbus spacecraft - a satellite powered by a 470-Watt photovoltaic array.

Types of Energy Made From Solar Power

Electricity
A photovoltaic cell, commonly called a solar cell or PV, is used to convert solar energy into electrical power.

Heat
When converted to thermal energy, solar energy can be used to heat homes, buildings, swimming pools, greenhouses, and other buildings

CURRENT USES

Solar energy provides 0.3 percent of the energy consumed in the U.S. today.

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SIMPLE USES

• Wrist Watches
• Calculators
• Passive Solar Technology (ex.windows)
• Solar Panels on Rooftops
• Street Lights

COMPLICATED USES

• Communication Satellites
• Water Pumps
• Outdoor Machines

Not used very much, but the number has been increasing!

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BENEFITS

Renewable (Environmental)

Solar power is a renewable resource

Earth-Friendly
(Environmental)

Solar energy systems do not produce air pollutants or carbon dioxide.

Silent
(Economical)

There are no moving parts involved in most applications of solar power. There is no noise associated with photovoltaics.

Improving Technology (Economical)

The technology for solar power is steadily improving with time.

Less Maintenance Required (Economical)

Solar panels usually only require cleaning a couple of times a year.

Portable

Conversion from sunlight to electricity is direct in photovoltaics, so bulky mechanical generator systems are unnecessary.

DRAWBACKS

Expensive (Economical)

Even the best value solar panel costs $183.30 for 235 Watts.

Intermittent

Access to sunlight is limited at night or poor weather. Predicting these can be difficult.

Require Space
(Economical)

In areas of low power density, too much land is required to provide the power we need at reasonable prices.

Exotic Materials (Environmental)

Some solar cells use materials that are rare in nature, like CdTe or CIGS.

FUTURE SUPPLY:
Solar Technology can last as long as the sun exists, but it will not be available at night.