- According to the U.S. Energy Information Administration, the definition of renewable energy is, "Energy sources that are naturally replenishing but flow limited. They are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. Renewable energy sources include: biomass, hydro, geothermal, solar, wind, ocean thermal, wave action and tidal action." In 2008, renewable energy resources supplied only seven percent of United States energy supply. In turn, solar energy comprised only one percent of United States total renewable energy supply.
- The sun's energy can be converted into heat and electricity. Scientists have been experimenting with solar energy since the 1830s, when astronomer John Herschel developed a solar thermal collector box that allowed him to cook food while on an expedition in Africa. In 1839, French scientist Edward Becquerel discovered the photovoltaic, or electricity producing potential of the sun's energy. In the early 1900s Albert Einstein won a Nobel Prize for further developing and explaining the concept of photovoltaics. In 1954 Bell telephone researchers developed the first practical photovoltaic cell.
- There are two types of solar power: thermal and photovoltaic. Thermal solar power collects the sun's energy and uses it to heat a fluid to a very high temperature. The fluid is circulated; transferring its heat to water and creating steam that is then converted into electricity by a steam generator.
Photovoltaic solar power uses a photovoltaic or PV cell to convert the sun's energy directly into electricity without the use of moving parts. PV cells are grouped together to form a module and modules are grouped together to form a panel. A solar array is the entire system of solar panels working together to produce electricity. Solar panels can generate electricity on a stand-alone basis or they can connect to the electrical grid which allows unused energy produced by the panel to be transferred back to the electrical grid. - Photovoltaic electricity provides numerous economic and environmental advantages over fossil-based and other renewable energy sources. Photovoltaic electricity is a clean, non-polluting energy source. Unlike renewable sources such as wind, water and solar thermal power, solar panels do not require moving parts that are noisy, break or require maintenance. Electricity from solar panels does not require large-scale installation. Small systems can be installed on homes to provide a portion or all of the homes electricity needs. Many municipalities use very small photovoltaic systems to provide electricity for roadside call boxes and street signs.
The primary disadvantages of photovoltaic electricity are the price of equipment and installation and the variation in sunlight due to geographical conditions and weather. Currently, the cost to install a photovoltaic system capable of supplying electricity for an entire household is out of reach for most homeowners. Likewise, most businesses and government entities will require financial assistance in the form of grants or rebates to make photovoltaic electricity a financially viable option. Certain geographic locations are not ideal for photovoltaic use. In most applications photovoltaic panels require direct sunlight for several hours each day to produce the required amount of electricity. Areas that receive only a few hours of sunlight, are surrounded by trees or experience prolonged periods of cloudy weather are not ideal locations for photovoltaic panels. - Photovoltaic technology is highly sought after by developing nations where the installation of conventional power lines is either too expensive or impractical. The Indian government plans to use photovoltaics to extend electricity and phone service to remote villages around the country. Mexico plans to use solar power to provide electricity to 60,000 remote villages and Zaire operates its busiest hospital entirely on electricity produced through photovoltaics. Developing countries are also using photovoltaic electricity to sterilize and treat water which will provide remote areas and villages with clean, safe drinking water.
Definition of a Renewable Energy Resource
History of Solar Power
Types of Solar Power
Advantages and Disadvantages of Photovoltaic Electricity
Photovoltaics in Use around the World
SHARE
