What Is the Difference Between Direct and Indirect Solar Power?

by admin on November 16, 2010

 

Solar power is abundantly available around the globe, but it has barely begun to be tapped.  People have just recently started to use solar power to directly harness the sun’s force.  However, indirect solar power has always been used.  Taking a look at the two will show the differences. 

To get direct solar power, the energy from the sun must undergo only one change to make it into a usable form.  Direct solar power is any kind of energy that is obtained from the sun in this way.  Direct solar power could come in various forms.

When photovoltaic cells receive sunlight and make electricity, it is direct solar power.  The sunlight only goes through one conversion between the sun’s energy and electricity. 

Fiber optic cables are a source of solar power.  They can be mounted outside so that the energy they receive through the sun can be converted into light for the insides of buildings.  This allows for some extra lighting, but at this time it is not usually the only source of light in an interior. 

Another type of direct solar power is a solar thermal collector.  It has a dark surface that absorbs sunlight.  This causes the surface to get warm.  This heat is converted into energy and used in a fluid circuit. 

Spacecrafts use solar power also.  This is direct solar power, as there is a solar sail in the craft that collects sunlight to energize the craft and put it into motion.  This is an ideal source of energy for a spacecraft which has ample sunlight and can carry only limited supplies of most other fuels. 

Indirect solar power has been around for millennia.  It is the kind of solar power that goes through more than one change to become usable energy.  It can be seen as the result of the effects the sun has on the world naturally.  Mankind may use the energy, but the sun’s power has already been concentrated for them. 

Anything that can be grown in fields or in the wild and can be used for energy has indirect solar power.  Plants use photosynthesis to change light energy into chemical energy – that is the first conversion.  Then, for example, tree limbs could be used to create heat energy in a fire. Plants could be converted into bio-fuels to create electricity. 

Actually, fossil fuels such as oil and coal are forms of indirect solar power.  The living things that made them used solar power to survive long before they were turned into coal or oil.  Yet, these fuels are rarely thought of as solar power because they are not renewable sources of energy. 

Even wind turbines and hydroelectric dams can be influenced by the sun’s energy.  The sun heats up the atmosphere and makes changes in the winds and the weather.  Indirect solar power is indeed all around.   The day when direct solar power has the kind of impact on human life as indirect solar power does will be very different from today. 

Previous post:

Next post: