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Solar Electricity, The Basics

Grid interactive power systems can be used to supply electricity to a business or a home. Grid interactive power is no different to normal grid connected power except that you have solar panels on the roof. Also you know the power supplied to your home is environmentally friendly and from the day after it was set up it was free. This type of power is often called off set power as the power generated by the system off sets the power used in the home. If the power generated by the system is more than the power used in the home the system will be in credit. In some countries like Germany, the power will not only provide you with a power credit but will in fact pay you for the extra power generated for the grid.

This system is made up of the following components:

Photovoltaic cells, DC circuit breaker, inverter, AC circuit breaker, and a bidirectional utility grid meter.

Photovoltaic Cells:

These are the main components of the system. These panels define the system and change the sun light (not heat) into power via the photo chemical action of the photovoltaic cells. The photons (sunlight) excite the electrons in the solar cell and electrons flow in the form of electrical current. This process is also called the photovoltaic effect and thence the name photovoltaic cells. The photovoltaic panels are given a wattage ratings based on the maximum power they can produce under ideal temperature and sunlight conditions. Solar panel produce more power in colder conditions however unless temperature extremely high there will not be a lot difference. Panels mostly come in the form of a ridged panel that is mounted in a frame or on the roof. However there are now many forms of solar panels for the home. Some are flexible, mounted on roof shingles and tiles, and roofing systems that are solar panels and roofing sheets combined.

DC circuit and AC circuit Breakers:

DC or Direct current circuit breaker simply allows you to turn off the power produced by the solar cells when servicing of adding to the solar array. AC or Alternating current circuit breakers are 240v based and enable the 240v power produced by the system to be turned off.

Inverter:

An inverter is used to take the power produced by the solar panel array and transform it into 240volts to be used in the home or fed back into the grid. Inverters take the DC power and transform this power into alternating current and step it up to 240v. Some inverters can charge batteries from the grid when the sun is not shinning and then feed the grid when the batteries are full. However in a grid based system the inverter manages the power in the system by feeding the grid when the panels are producing and taking power from the grid when the sun is not out and feeding the house with power. Also if your area is suitable a small wind turbine can be added to the system for extra power to the system.

Bidirectional Grid utility meter

Normal grid power meters cannot be used as they only feed into the house. In a grid based solar system, bidirectional grid meters are used so that they can meter the power into and out of the grid. Thus the meter will measure the power put into the grid by the solar array and it will measure the power taken from the grid to be used in the home.