What is Solar Energy?

The Law of Conservation of Energy:

• Energy can only change from one form to another.
• Energy can not be created or destroyed.

Solar Energy is the energy from the Sun.  The Sun is a big ball of heat and light resulting from nuclear fusion at its core.  The nuclear reaction releases energy that travels outward to the surface of the Sun.  Along the way to the surface the energy transforms so that by the time it is released it is primarily light energy.  Sunlight.  The two major types of solar energy that make it to Earth are heat and light.
Solar energy is often called "alternative energy" to fossil fuel energy sources such as oil and coal.

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One example of our use of solar heat energy is for water heating systems.  A solar panel is used to collect heat.  The heat is transferred to pipes inside the solar panel and water is heated as it passes through the pipes.  The hot water, heated by the Sun, can then be used for showers, cleaning, or heating your home.
We also use solar thermal energy through passive solar designs.  Windows or skylights in your home can be designed to face the Sun so that they let heat into the house, keeping you warmer in the winter.
The light energy from the Sun can be transformed into electrical energy and used immediately or stored in batteries. Photovoltaic (PV) panels are the devices that convert light energy into electrical energy.

Energy changes from one Form to Another.

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Let's look at a solar powered vehicle that runs on electricity directly from solar energy as a simple example in the transformation of energy from one form to another.

• Sunlight hits the PV panel and the panel transforms the light energy into electrical energy.
• The electrical energy (electricity) passes through the wire circuit to the motor.
• The motor transforms the electrical energy into mechanical energy to turn the drive shaft which turns the wheels.
• The wheels rotate on the ground to move the vehicle transforming mechanical energy into vehicle motion (kinetic energy).

Solar Vehicle Ideal Energy Chain:  
Light Energy >> Electrical Energy >> Mechanical Energy >> Kinetic Energy

Energy transformation is not perfect.....

The above case is ideal because not all systems are perfect and in reality there will be losses of energy from our system.
In a simplified view of this case some losses will be from:

• friction of electrons passing through the wires;  this is released as heat energy.
  
• friction of the drive shaft or wheels on the ground;  this is released as either heat or sound energy.
  

Even with these losses the law of conservation of energy still holds.  The amount of energy into a system will always equal the amount of energy out of a system.