Grid Intertied Solar-Electric System
There are a number of ways through which you can reduce your energy consumption and therefore slash energy
costs. Using renewable sources is the most obvious means of complimenting a home’s energy needs.
There are other subtle measures you can take to achieve this, such as being mindful about wastage and switching
off appliances while not in use, using appliances that are less energy intensive, conserving water to reduce
heating, among others.
The most common form of renewable energy is solar. It is usually
the first choice of alternative energy for most homeowners who consider a renewable source to compliment their
power needs. It is also relatively cheaper and generates slightly more energy for its price, compared to wind for
A solar electric system consists of many components but the solar cells, inverters and batteries are the core
parts. The solar cells (photovoltaic cells) absorb solar energy – by means of a special semiconductor material
usually silicon – and convert it to direct current, which is then converted into usable alternating current by the
converter. It is then transmitted to the batteries for storage and distribution.
In a grid intertie solar system, a DC-AC inverter has more functions other than just converting direct current
to alternating current.
Grid intertie system
Power intermittency of solar (and wind electric systems) is what necessitates a grid intertie system. A grid
intertie system is one where your private solar
electric system is wired onto your utility grid’s supply system. At the center of this intertie system is the
inverter, which does the following functions:
• It continuously monitors any voltage changes in the utility company’s electric supply, as well as
monitoring outages and frequency changes. The inverter is designed in such a way as to switch off automatically in
the event that there’s serious electrical variance or in case of grid failure.
• The inverter collects and displays (on an LCD screen) information about the solar system’s overall
performance, which includes real-time and past power generation, as well as the working status of the inverter
• Another important function of the inverter is to synchronize the alternating current from the grid with
that it produces, which it then feeds into the meter and then to the grid. Because your solar system is generating
power, your meter will slow down depending on how much is produced and, in some cases it will run backwards when
the all the power being produced is not used.
In states that allow ‘net-metering’ such as California, the utility company will give you credit (at retail
price rate each time your meter runs backwards.
Normally, you will not receive a payment in cash form in a net-metering system but the credit you receive when
you produce excess power is carried forward to the ensuing months until it is used up. If you constantly generate
excess power, you can forget about energy bills altogether and the return on investment on your solar system can
take a few years.
An inverter basically provides the convenience and simplicity of plug and play in a grid intertie system.