WHAT IS SOLAR POWER?

Solar Power  is energy from the sun.

Introduction    How it Works    Advantages    Disadvantages    Is it Renewable?

INTRODUCTION

The sun has been used for drying clothes and growing food for thousands of years, but only recently has the sun been used for solar power.

Concerns over pollution, environmental degradation, and resource depletion have led to an increasing awareness of the importance of developing solar energy.

Just the tiny fraction of the sun's energy that hits the Earth (around a hundredth of a millionth of a percent) is enough to meet all our power needs many times over.

In fact, every minute, enough energy arrives at the Earth to meet our demands for a whole year - if only we could harness it properly.

HOW IT WORKS

The sun provides the Earth with two major forms of energy: heat and light. There are some solar powered systems that utilize heat energy while others transform the light energy into electricity.

There are three ways to harness the sun's energy for use in our homes: solar cells, solar water heating, and solar furnaces.

SOLAR CELLS

Solar cells directly convert light into electricity. Solar cells are also called "photovoltaic" or "photoelectric" cells. Enough power can be generated to run a 100W light bulb from just one square meter of solar panel. Solar cells were originally developed in order to provide electricity for satellites. Today solar cells are used in everyday applications, such as calculators and outdoor lighting. For more detailed explanations of how photovoltaics work, the following sites are recommended: The U.S. Department of Energy has produced a QuickTime video of how a PV cell works. QuickTime video

SOLAR WATER HEATING

Solar water heating is used to heat water in glass panels located on a roof. This conserves gas and electricity to heat water in a home. Water is pumped through pipes in the panel. To maximize the heat transfer from the sun, the pipes are painted black. This helps the central heating system and cuts the cost of energy bills.

SOLAR FURNACES

Solar furnaces use a large array of mirrors to concentrate the sun's energy into a small space to produce very high temperatures. The solar furnace shown in this picture is located in Odellio, France. It is used for scientific experiments and can achieve temperatures up to 33,000 degrees Celsius.

ADVANTAGES

• Once solar panels are installed, they produce energy without generating waste or pollution. They operate with little maintenance or intervention.
• Solar electric generation is economically competitive where grid connection or fuel transport is difficult, costly or impossible. For example: satellites, island communities, remote locations and ocean vessels.
• Once the initial capital cost of building a solar power plant has been met, operating costs are low when compared to existing power technologies.
• They are applicable for low-power uses such as solar powered garden lights and battery chargers.
• A solar panel saves approximately 0.7 pounds of coal per kWh, or 2 pounds of carbon dioxide per kWh. To see how much carbon dioxide our panel has saved, Click Here.

Over its 35-year expected life, a 10 kW system will provide CO2 reduction equivalent to planting 1450 trees. In comparison to a coal fired power plant, a 10 kW system will prevent emissions of 960,000 lbs carbon dioxide, 4,200 lbs sulfur dioxide, and 1,400 lbs nitrogen oxides. It will produce 575,000 kilowatt hours of electricity, as much as would be generated by burning 583,000 lbs coal.

DISADVANTAGES

• Solar energy systems do not work at night.
• Solar cells are currently costly and require a large initial capital investment.
• For larger applications, many photovoltaic cells are needed, corresponding to high investment costs and large land requirements.
• The cost effectiveness of a solar energy system is dependent upon the location and climate.