Photovoltaic systems have become a popular solution to generate electricity from renewable and clean sources without harming the environment, such as solar energy.
Two major variants of these systems are off-grid and on-grid photovoltaic systems, each with distinct characteristics and benefits of their own. Let’s explore the differences and advantages offered by these two types of systems.
Off-Grid Photovoltaic Systems: Energy Independence and Autonomy
Off-grid photovoltaic systems are electricity production systems using solar panels, which are not connected to the public electricity grid. These systems are completely self-contained and provide electricity for isolated locations or for situations where access to the centralized power grid is unavailable or impractical.
The main features of off-grid photovoltaic systems include:
Solar panels: These are the key equipment of the system and are composed of photovoltaic cells that convert solar energy into continuous direct current (DC) electricity.
Charge Controller: A device that regulates the charging of energy storage batteries to prevent overcharging and overdischarging.
Storage batteries: to ensure power supply during periods when the sun is not shining or during the night, off-grid systems use batteries to store excess energy produced during the day.
Inverter: This device converts direct current (DC) stored in batteries to alternating current (AC), which is the form of electrical current used in most electrical equipment and devices.
Monitoring and control systems: To ensure efficient operation of the system and to avoid overloads or shortfalls in power supply, some off-grid systems include monitoring and control technologies.
Power planning: Users must carefully manage their power consumption as resources are limited. This can involve planning energy use based on solar availability and battery stock.
Installation and maintenance: Installation and maintenance of off-grid PV systems requires technical expertise to ensure optimal long-term operation.
On-Grid Photovoltaic Systems: grid integration
On-grid (or grid-tied) photovoltaic systems are electricity production systems using solar panels, which are connected to the public electricity grid.
This system allows users to generate electricity from renewable sources, like solar power, and inject it into the local power grid. The main features of on-grid photovoltaic systems include:
Solar panels: These are the main equipment of the system and convert solar energy into direct current (DC) electricity.
Grid-tied inverter: This is an essential component of the system, which converts the direct current (DC) generated by the solar panels into alternating current (AC) in accordance with the characteristics of the local power grid.
Two-way meter: on-grid systems are equipped with special meters that measure the electrical energy produced by the system and injected into the electrical grid, as well as the electrical energy consumed from the electrical grid.
Grid connection: excess electricity produced by the photovoltaic system can be fed into the public grid. This surplus energy can be used by other consumers in the network.
Energy compensation: If you become a prosumer, on-grid system owners can benefit from an energy compensation system, where the excess electricity produced is recorded and deducted from their energy bill, which can lead to significant savings.
Monitoring system: On-grid systems may have monitoring systems to track the performance and energy production of the system in real-time.
On-grid PV systems are popular in urban areas and locations with a developed electrical infrastructure. They provide a way to generate clean energy and save on energy costs while also contributing to the overall sustainability of the electricity grid by providing renewable energy.
The difference between an on-grid and an off-grid photovoltaic system
The main difference between an on-grid PV system and an off-grid PV system is how they are connected to the electricity grid and to what extent they depend on it:
On-grid photovoltaic system:
Grid connection: An on-grid photovoltaic system is connected to the public electricity grid. Solar panels generate electricity, which is converted from direct current (DC) to alternating current (AC) by a grid-tied inverter.
Injection into the grid: The electricity produced in excess by the solar system is injected into the public electricity grid. It can be used by other consumers in the area.
Energy compensation: Owners of on-grid systems can benefit from an energy compensation system – the prosumer quality. The electricity produced in excess is recorded and deducted from the energy bill.
Grid Dependency: An on-grid system does not supply power in the event of power outages in the public power grid. It shuts down automatically to protect network maintenance workers.
Off-grid photovoltaic system:
Grid-independent: An off-grid photovoltaic system is completely independent from the public power grid. Solar panels generate electricity, which is stored in batteries for later use.
Energy storage: Batteries are used to store excess electricity produced during the day so that it can be used at night or during periods of high demand.
Non-grid dependence: Off-grid systems can provide power even when the public power grid is unavailable or non-existent.
Power management: Because stored energy is limited, users must carefully manage their power consumption.
Essentially, an on-grid photovoltaic system is tied to the electricity grid and can contribute to its supply, benefiting from energy offsets. In contrast, an off-grid photovoltaic system is independent and does not depend on the public grid, using batteries to store and provide energy autonomously.
The choice between the two types of systems depends on the energy needs, accessibility to the electricity grid, and the level of energy independence desired.
The choice between off-grid and on-grid photovoltaic systems depends on the needs, location, and priorities of each user. Off-grid systems offer independence and autonomy, while on-grid systems ensure grid integration and energy savings.
In both cases, the adoption of solar energy brings lasting benefits, contributing to global sustainability and greater energy independence. Consulting with a solar energy expert or solar panel supplier can help you make the best decision for your needs.