Solar Energy ...
Solar energy is the oldest form of energy and all living things depend on it. It is defined as energy from the sun that is converted into thermal or electrical energy.
Solar energy has become increasingly popular because compared to depletable energy (for example, oil, coal and nuclear), solar energy is renewable and offers an environmentally clean and safe form of energy.
The possibility of scarce oil resources has forced both developed and developing counties to consider solar energy as a possible alternative energy source.
Indirect Solar Energy
Plants use the sunís energy to synthesize food by the process of photosynthesis.
Photosynthesis is define as the process in green plants and certain other organisms by which carbohydrates are synthesized from carbon dioxide and water using light as an energy source.
Most forms of photosynthesis release oxygen as a byproduct.
Biomass derived fuels refer to wood and dry crop waste and are indirect forms of solar energy.
About a century ago, firewood was still the most common form of fuel. Today, it is still used widely in most developing countries although other forms of energy are currectly available.
Unfortunately, it is one of those renewable energies that is hard to replenish at the rate at which it is used.
Wind effects are a result of a variation of pressure between different areas caused by solar energy.
Therefore, wind power is also an indirect form of solar energy. In fact, it is the cheapest source of solar electricity.
This form of energy is used to run turbines that in turn generate electricity. Unfortuantely, not many places average a wind speed that makes it an attractive souce of solar electricity.
Photovoltaic (PV) cells or solar cells are devices that directly convert solar energy (sunlight) into electrical energy.
That is, they are capable of producing a voltage when exposed to radient energy, especially light.
This phenomenon was first discovered in the 18th century. Fortunately, the cost of developing photovoltaic cell technology has dropped significantly to make it cost effective.
The simplest form of the photovoltaic cell can be found powering such things as calculators and watches; while more complex systems drive vehicles (e.g., cars, bicycles, etc.), power refrigerators, heat water and light houses, to mention a few.
Photovoltaic cells have also found a place in space technology and are found in satellites and the Hubbell telescope which utilizes solar panels for its energy requirements.
Future of Solar Energy
The success of solar energy will largely depend on the efficiency of (i) cells that convert solar energy (sunlight) to electricity and (ii) auxiliary systems that store this electricity.
Such auxiliary systems are crucial to the future of solar energy because sunlight is only gareenteed for so many hours daily, and direct sunlight many range from 0+ daily.
Unfortunately, systems for storing solar energy are not available today. Much research is still needed in all areas.