Different types of renewable energy systems perform different functions. For
example:
• Photovoltaics (PV) convert sunlight directly
into electricity using PV cells made of semiconductor material.
• Concentrating Solar Power
(CSP) systems concentrate the sun’s energy using reflective devices, such
as troughs or mirror panels, to produce heat that is used for industrial processes
or to generate electricity.
• Solar water heating systems heat water,
either directly or by heating a “working fluid” that then heats
the water. Solar water heaters are commonly used to heat domestic water in homes;
heat water for swimming pools, spas and hot tubs (a particularly cost-effective
application); or to heat water for industrial processes.
• Transpired solar collectors use solar energy
to preheat ventilation air.
• Passive solar energy designs use the building
itself as both the solar collector and storage medium, usually by increasing
the window area on the south side of the building and the amount of thermal
mass inside the building to absorb the solar heat that enters through the windows.
• Daylighting systems provide light during
the day, significantly reducing the cost of, and heat gain from, electric lighting.(www.ases.org
retrieved 7/19/04)
Link to EERE , the Department of Energy (DOE) and The American Solar Energy Association (ASES) for more information
Renewable energy sources are clean and inexhaustible. The money spent on renewable energy installations tends to remain in the community, creating jobs and fueling local economies. The use of renewable energy equipment also reduces our dependence on foreign and/or centralized sources of energy, and is an important strategy in the process of creating a truly secure and sustainable energy future.(www.ases.org retrieved 7/19/04)
Typically, the energy payback time (the time it takes the system to generate the same amount of energy that it took to manufacture the system) for PV systems is two to five years. Given that a well-designed and maintained PV system will operate for more than 20 years, and a system with no moving parts will operate for close to 30 years, PV systems produce far more energy over their lives than is used in their manufacture.(www.ases.org retrieved 7/19/04)
Link to NASA's site for the answer.....Science @ NASA