Using Solar Energy to Generate Electricity
The challenge of using solar energy to generate electricity has fascinated scientists and environmentalists for years. The sun is the source of much of the earth's energy.
It is the source of rain and snow as the rays of the sun evaporate oceans and lakes and pulls that moisture into the atmosphere to be returned as moisture to the earth's surface.
It is the energy from the sun that is responsible for the lush plant and tree growth and we all know the pleasure of standing in the warm sun on a chilly day.
The beauty of solar energy is that creating electricity from sunlight does not use any of the earth's resources. The sun provides energy constantly and is our primary source of renewable, clean energy.
Using Solar Energy to Produce Electricity - Two Methods
Turning the sun's power into electricity can be done using two methods. The first is photovoltaic and the second is called solar-thermal.
Photovoltaic (PV) was developed for the space program more than thirty years ago. It operates as a fuel cell and depends on a chemical reaction in using solar energy to produce electricity. A PV cell is a small, square semiconductor composed of multiple thin layer of silicon and other highly conductive materials.
Sunlight strikes the PV cell and a chemical reaction releases electronic which generated electricity. PV cells are installed in modules known as solar panels and can power homes or can be routed to the larger power grid.
A traditional generating tactic is solar-thermal technology. The sun's heat is used to create steam which then powers an electric generator.
In California, there are parabolic trough systems that use solar-thermal methods. Reflectors focus and concentrate the sun's rays and heat oil which then creates steam used to drive a turbine.
The methods above are the most common ways of using solar energy to generate electricity. Parabolic dish systems concentrate the power of sunlight and heat gases. This creates pressurized gas or steam to generate electricity.
Central receive systems are another way of using solar energy to produce electricity where mirrors reflect sunlight and direct it to a fluid filled tube or tower. The heated fluid in the tower creates steam that can be used to power an engine.
Environmental Impact of Using Solar Energy to Generate Electricity
Photovoltaic collection systems do not produce the air, water or sold waste commonly associated with use of fossil fuels. If creating a large energy producing system, you do need a good amount of land for installation of the PV panels. This is often a problem that can be avoided by installing the PV panels on the roofs of buildings.
Some hazardous materials can be involved in the manufacturing of PV cells but his is controlled carefully with strict handling procedures and manufacturing standards.
Solar-thermal versions have zero emissions but again may have some emissions involved with manufacturing of the systems. Solar thermal does require high amounts of water and water use in a large solar thermal system is about the same as for a nuclear or coal fired electric production facility.
The big concern in using solar energy to generate electricity is the issue of land use. One megawatt of electricity produced may require five acres of land for cell installation. The current trend in architecture is to build with the goal of using solar energy to protect the environment.
This means designing new construction with a view to installation of solar panels on roofs or southern exposures to eliminate the need for high land use. This is especially important when using solar energy in urban areas where open land is scarce or not available.
Using solar energy to generate electricity is a movement that is driven by a social consciousness today but also by practical considerations. When gas and oil were cheap there was little interest in investing money in new unproven technology.
The oil embargos of the 1970s changed the public perception of electric energy. Added to that scarcity potential was an increasing concern about the pollution of our environment that is a direct result of using fossil fuels for energy production.
Today the focus on using solar power is big news. It is a popular idea fully supported by a public anxious to find an affordable energy source that will protect the earth and be dependably available into the future.
The increased production of solar panels has led to lower prices. Builders are now aware of solar power and know how to design and build homes using solar energy to generate electricity.
In time, it's possible a huge solar grid will be able to provide the majority, if not all, of the energy needs in the country. This would remove the uncertainty of when fossil fuels might be depleted and avoid the worries about wars and political unrest in oil producing countries.