Solar energy systems can be classified into two main categories: off-grid and on-grid. Each one has unique characteristics, being suitable for different needs and scenarios.
The off-grid system
The off-grid system is a solar power generation system that is independent of the power grid. This means that it is able to function self-sufficiently, storing the energy generated in batteries for later use.
Overall, we can summarize this system in a few main components:
- Photovoltaic Modules (Panels): Convert solar radiation into continuous electrical energy, installed with appropriate orientation and inclination, avoiding constant shadows.
- Charge Controller: Provides stable voltage to the battery bank and monitors the discharge of the batteries to optimize usage and lifespan.
- Battery Bank: Stores energy to provide autonomy to the system, composed of stationary batteries connected to obtain the correct voltage, carefully sized due to cost.
- Mounting Structure: Supports and fixes the solar panels at the installation site.
- Inverter: Converts direct current to alternating current power, and must provide enough power for all equipment connected to off-grid systems.
- Monitoring system: Complementary to the main components, it allows the collection of generation, current, voltage, power data and even remote management of the off-grid system.
This system is ideal for remote areas where there is no access to the conventional power grid or for people who want to be completely energy independent. Some of the examples of off-grid system application include:
- Residences in rural areas;
- Cabins and cottages;
- Isolated communities;
- Emergency facilities.
The on-grid system
The on-grid system, on the other hand, is connected to the electricity grid - and is precisely the most common type in urban centers. This type of system allows the energy generated to be used directly in the home, or establishment, and the surplus to be sent to the grid, generating credits that can be used later.
Its essential components are:
- Solar Panels: Convert solar radiation into electrical energy, just like in the off-grid system.
- Inverter: Converts the power generated by the panels from direct current (DC) to grid-compatible alternating current (AC).
- Mounting Structure: Supports and fixes the solar panels at the installation site.
- Bidirectional Electricity Meter: Measures the energy consumed from the grid and the energy generated by the photovoltaic system, allowing the control and balancing of energy from the grid and solar generation.
- Connection to the Electricity Grid and Distribution Board: Interconnects the photovoltaic system with the public grid and distributes the electricity generated for internal consumption.
In this system, the storage battery bank for energy retention is optional. But beware: by choosing not to install, the system is limited to supplying energy only during periods of sun exposure – since the night supply, for example, is supported by the battery bank, when the panels are not generating energy.
The on-grid system is popular in cities due to its ability to reduce energy costs over time. And of course, the most classic application cases include:
- Residences in urban areas;
- Companies and businesses;
- Public buildings;
- Educational institutions.
If you are thinking of installing a solar energy system in your home or business and are asking yourself this question, it is good to keep in mind: the choice between an off-grid and on-grid system depends on your specific demands and the context of where the installation will be done.
In general, for remote areas or for those who want total independence from the electricity grid, the off-grid system is ideal. For those who want to save on their electricity bill and contribute to the electricity grid, the on-grid system is the best option.
Advantages and disadvantages of the on-grid system
To summarize and help you better understand what to consider when choosing, let's take a quick look at the main advantages and disadvantages that on-grid system users usually comment:
Advantages:
* Significant reduction in the electricity bill;
* Possibility of selling the surplus energy generated;
* Lower initial cost compared to the off-grid system.
Disadvantages:
* Dependence on the power grid;
* It only works in the event of a mains outage if combined with batteries.
Advantages and disadvantages of the off-grid system
And similarly, the strengths and weaknesses of the off-grid system typically include:
Advantages:
* Total independence from the electricity grid;
* Ideal for remote areas without network access;
* Increased resilience in emergency situations.
Disadvantages:
* Initial cost is higher;
* It requires more care with maintenance.
TNE POWER offers a variety of battery solutions for both on-grid & off-grid solar system, residential & commercial, including lead acid VRLA AGM or GEL batteries, tubular OPzS & OPzV batteries, lithium LiFePO4 batteries in wall mount/rack mount and stack type.