SOLAR PHOTOVOLTAIC POWER - PV
Photovoltaic technology makes use of the abundant energy in the sun, and it has little impact on our environment. Photovoltaic can be used in a wide range of products, from small consumer items to large commercial solar electric systems. In very remote locations it may be the only practical solution for reliable power cannot be provided virtually everywhere, especially the most part of developing countries.
In addition, more and more residential and commercial customers worldwide, are realizing the benefits of utilizing solar power for electricity to offset their utility-supplied energy consumption, to provide back up power or to operate independent of the utility grid. Solar power can be a solution.
WHY PV IS IMPORTANT
Photovoltaic (PV) is an important energy technology for many reasons. As a solar energy technology, it has numerous environmental benefits. As a domestic source of electricity, it contributes to the nation's energy security. As a relatively young, high-tech industry, it helps to create jobs and strengthen the economy. As it costs increased less to produce and use, it becomes more affordable and available. And there are many more reasons, as we shall see.
Few power-generation technologies have as little impact on the environment as photovoltaic. As it quietly generates electricity from light, PV produces no air pollution or hazardous waste. It doesn't require liquid or gaseous fuels to be transported or combusted. And because its energy source - sunlight - is free and abundant, PV systems can guarantee access to electric power. PV frees us from the cost and uncertainties surrounding energy supplies from politically volatile regions.
STAND ALONE PV SYSTEMS
Stand-alone PV systems are often best in places where utility-generated power is either unavailable (because the area is so remote from power plants), undesirable (because of a possible utility power outage in an emergency), or too costly to hook up to (because of the price of extending power lines). Stand-alone systems are also excellent for uses that don't require a lot of power.
The electricity is used to power water pumps for irrigation and drinking wells, for example, or ventilation fans for cooling. For this reason, the most simple PV systems are those that generate direct-current (dc) electricity so it can be used right away to run water pumps, fans, and many other appliances that use dc electricity. These basic PV systems have several advantages that make them suitable for these jobs. First, they produce energy where and when it's needed, so complex wiring, storage, and control systems aren't needed.
Second, small systems that produce less than 500 watts and weigh less than 68 kilograms (150 pounds) are easy to transport and install. Most installations take only a few hours. And, although pumps and fans require regular maintenance, PV modules require only an occasional inspection and cleaning.
PV SYSTEMS WITH BATTERY BACKUP
PV systems with batteries for storage are excellent for supplying electricity when and where you need it. These systems are especially suitable in areas where utility power is unavailable or utility line extensions would be too expensive.
The ability to store PV-generated electrical energy makes the PV system a reliable source of electric power both day and night, rain or shine. PV systems with battery storage are used all over the world to provide electricity for lights, sensors, recording equipment, switches, appliances, telephone, televisions, wireless signal towers and even power tools! We operate PV/battery systems by connecting the photovoltaic modules to a battery, and the battery, in turn, to the load. During the day, the PV modules charge the battery, and then the battery supplies power to the load as needed. A simple electrical device called a charge controller keeps the batteries charged properly and helps prolong their life by protecting them from overcharging or from being completely drained.
GRID-TIE SYSTEM
Grid-tie systems generate electricity, sending this energy back to your utility company's power grid. In effect, this means the utility company will be paying you to produce energy for them, since the energy you produce counts against the energy your home or business uses.
Your solar panels will produce DC (Direct Current) electricity. This electricity will be run through an inverter to produce AC (Alternating Current) electricity. This energy is then run into your AC power panel, which feeds energy back to your utility company's power grid. If your solar power array produced enough electricity, your utility meter would begin to run backward!