What is Solar Energy
The sun has produced energy for billions of years. Solar energy is the sun's rays (solar radiation) that reach the Earth. This energy can be converted into other forms of energy, such as heat and electricity. The Earth receives 174 petawatts (PW) of incoming solar radiation (insolation) at the upper atmosphere. Approximately 30% is reflected back to space while the rest is absorbed by clouds, oceans and land masses. The spectrum of solar light at the Earth's surface is mostly spread across the visible and near-infrared ranges with a small part in the near-ultraviolet. Earth's land surface, oceans and atmosphere absorb solar radiation, and this raises their temperature. Warm air containing evaporated water from the oceans rises, causing atmospheric circulation or convection. When the air reaches a high altitude, where the temperature is low, water vapor condenses into clouds, which rain onto the Earth's surface, completing the water cycle. The latent heat of water condensation amplifies convection, producing atmospheric phenomena such as wind, cyclones and anti-cyclones. Sunlight absorbed by the oceans and land masses keeps the surface at an average temperature of 14 BC. By photosynthesis green plants convert solar energy into chemical energy, which produces food, wood and the biomass from which fossil fuels are derived.
Solar power is energy from the sun and without its presence all life on earth would end. Solar energy has been looked upon as a serious source of energy for many years because of the vast amount of energy that is freely available, if harnessed by modern technology. A simple example of the power of the sun can be seen by using a magnifying glass to focus the sun's rays on a piece of paper. Before long the paper ignites into flames.
Solar power is the conversion of sunlight into electricity, either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP). Concentrated solar power systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. Photovoltaics convert light into electric current using the photoelectric effect.
Advantages of Solar Energy
Solar energy enjoys many environmental and economic advantages over other forms of energy currently used. These include:
- Non-polluting: Solar electricity generation produces no emissions while the current alternative, fossil fuel combustion, releases more than a pound of carbon dioxide emissions for every kilowatt hour.
- Non-consumptive: The suns radiation is a limitless resource that can be collected without the environmentally destructive processes of mining or pipelines.
- Cost effective: Solar generated electricity is already cheaper than conventional electricity in many major US cities. By 2027, PV will be the most cost-effective solution (even without any government subsidies or advantages from its environmental cleanliness) in nearly all areas of the United States.
- Immediate and permanent savings: Properly financed systems will provide consumers with cheaper electricity from the day of installation.
- Technological advancements: Improvements in solar technologies offer reduced costs and greater efficiency.