SOLAR SYSTEM
GRID TYPES
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• All solar power systems work on the same basic principles
• Solar panels first convert solar energy or sunlight into DC
• The DC power can then be stored in a battery or converted by a solar inverter into AC
power which can be used to run home appliances
• Depending on the type of system, excess solar energy can either be fed into the
electricity grid for credits, or stored in a variety of different battery storage
systems
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Solar System

The Three Main Types Of Solar Power Systems
• On-grid - also known as a grid-tie or grid-feed solar system
• Off-grid - also known as a stand-alone power system (SAPS)
• Hybrid - grid-connected solar system with battery storage
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Main Components Of A Solar System
• Solar panels are made up of many silicon based
photovoltaic cells (PV cells) which generate direct
current (DC) electricity from sunlight
• Solar panels can generate energy during cloudy and
overcast weather, but the amount of energy
depends on the 'thickness' and height of the clouds,
which determines how much light can pass through
• The amount of light energy is known as solar
irradiation and usually averaged over the whole day
using the term Peak Sun Hours (PSH)
• The PSH or average daily sunlight hours depends
mainly on the location and time of year.
Note: It is sunlight or irradiance, not heat, which produces
electricity in photovoltaic cells.
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Main Components Of A Solar System
Solar panels generate DC electricity which must be
converted to alternating current (AC) electricity for use in
our homes and businesses. This is primary the role of
the Solar Inverter
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• Batteries used for solar energy storage are available in two main types,
lead-acid (AGM & Gel) and lithium-Ion
• Most modern energy storage systems use rechargeable lithium-ion batteries
• Battery capacity is generally measured is either Amp hours (Ah) for lead-
acid, or kilowatt hours (kWh) for lithium-ion
• Lithium-ion based batteries can typically supply up to 90% of their available capacity
per day,
• while lead-acid batteries generally only supply 30% to 40% of their total capacity per
day to increase battery life
• Lead-acid batteries can be discharged fully, but this should only be done in emergency
backup situations.
Main Components Of A Solar System
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Main Components Of A Solar System
• In a common grid-tie solar system, AC electricity from the solar inverter is
sent to the Switchboard where it is drawn into the various circuits and
appliances in your home
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On-Grid System
• On-grid or grid-tie solar systems are by far the most common and widely used by homes and
businesses
• These systems do not need batteries and use either solar inverters and are connected to the
public electricity grid. Any solar power that you generate is exported to the electricity grid and
you usually get paid a feed-in-tariff (FiT) or credits for the energy you export
• Unlike hybrid systems, on-grid solar systems are not able to function or generate electricity
during a blackout due to safety reasons. Since blackouts usually occur when the electricity grid
is damaged; If the solar inverter was still feeding electricity into a damaged grid it would risk
the safety of the people repairing the fault/s in the network
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On-Grid System
• In an on-grid system, this is what happens after electricity reaches the switchboard
• The meter. Solar energy produced runs through the meter, which calculates how much power
you are either exporting or importing (purchasing)
• Metering systems work differently in many countries around the world. In some areas, the
meter measures both production and export, and the consumer is charged (or credited) for net
electricity used over a month or year period
• The electricity grid. Electricity that is sent to the grid from your solar system can then be
used by other consumers on the grid (your neighbours). When your solar system is not operating,
or you are using more electricity than your system is producing, you will start importing or
consuming electricity from the grid
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Off-Grid System
• An off-grid system is not connected to the electricity grid and therefore requires battery
storage
• Off-grid solar systems must be designed appropriately so that they will generate enough power
throughout the year and have enough battery capacity to meet the home’s requirements, even in
the depths of winter when there is generally much less sunlight
• The high cost of batteries and off-grid inverters means off-grid systems are much more
expensive than on-grid systems and so are usually only needed in more remote areas that are
far from the electricity grid
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• The battery bank. In an off-grid system there is no public electricity grid. Once solar power is
used by the appliances in your property, any excess power will be sent to your battery bank.
Once the battery is full it will stop receiving power from the solar system. When your solar
system is not working (night time or cloudy days), your appliances will draw power from the
batteries.
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Off-Grid System

Hybrid System
• Modern hybrid systems combine solar and battery storage in one
• Due to the decreasing cost of battery storage, systems that are already connected to the
electricity grid can start taking advantage of battery storage as well
• It is able to store solar energy that is generated during the day and use it at night. When the
stored energy is depleted, the grid is there as a back up, allowing consumers to have the best of
both worlds
• Hybrid systems are able to charge the batteries both sun and using cheap off-peak electricity
(usually after midnight to 6am)
•
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Hybrid System
• The meter and electricity grid. Depending on how your hybrid system is set up and whether
your utility allows it, once your batteries are fully charged excess solar power not required by
your appliances can be exported to the grid via your meter. When your solar system is not in
use, and if you have drained the usable power in your batteries your appliances will then start
drawing power from the grid.
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