A Complete Guide to the 4 Types of Solar Photovoltaic Systems

Thinking of going solar but not sure which system suits your needs? Whether you're connected to the grid, living off the beaten path, or seeking backup during blackouts, understanding the four main types of solar photovoltaic systems is key. This article provides a comprehensive overview of the four main types of Solar Photovoltaic Systems-On-Grid, Off-Grid, Hybrid, and Microgrid.

 

"Solar photovoltaic power generation" is a term that encompasses various expressions such as solar PV systems and Solar Photovoltaic Systems. At its core, it refers to the technology of directly converting sunlight into electricity. This process is based on the photovoltaic effect at the semiconductor interface, where photons striking a semiconductor material excite electrons, generating an electric current. Because this conversion bypasses any thermal stage, it offers high energy efficiency.

 

 

Based on current market applications and varying usage scenarios, solar PV power systems can generally be categorized into four main types:

• On-grid systems
• Off-grid systems
• Hybrid systems (on/off-grid with energy storage)
• Microgrid systems with mixed energy sources

 

1. Difference Between Off-Grid and On-Grid Solar Photovoltaic Systems

The key difference lies in whether the system relies on the external power grid.

 

On-grid (grid-tied) PV systems depend on the public grid and typically operate in two modes: "self-consumption with surplus fed to the grid" or "full power export to the grid." However, they do not function during power outages due to grid-safety regulations.

 

Off-grid PV systems operate independently of the grid, using modes like "store and use simultaneously" or "store first, use later." These systems are not affected by blackouts and can supply power even when the grid is down.

 

2. Components and Working Principle of On-Grid Solar Photovoltaic Systems

Main Components:

• PV panels
• Grid-tied inverter
• Electrical loads
• Bidirectional meter
• Grid connection cabinet
• Utility grid

 

Working Principle:

Solar panels generate DC electricity, which is converted into AC power by the inverter. This electricity is used to power household loads, and any surplus can be fed into the grid, often in exchange for credits or compensation.

 

 

 

Key Features:

• Connected to the utility grid: energy can be partially or fully exported.
• No power during grid outages due to anti-islanding protection required by utility companies.
• At night, power is drawn from the grid.
• No energy storage (no battery backup).

 

3. Components and Working Principle of Off-Grid Solar Photovoltaic Systems

As the counterpart to grid-tied systems, off-grid PV systems operate independently. These typically include:

• PV panels
• Off-grid inverter
• Battery storage
• Electrical loads

 

Some modern systems integrate the inverter and battery into an all-in-one unit. Off-grid systems are ideal for remote areas, off-grid villages, islands, telecom stations, and solar street lights.

 

 

 

Working Principle:

During sunlight hours, the system converts solar energy into electricity to power loads or charge batteries via the off-grid inverter.

In the absence of sunlight (e.g., at night or during cloudy weather), the system draws energy from the battery storage. Some systems also allow grid input to charge the battery when needed.

 

Key Features:

• Fully independent from the power grid; works as long as sunlight is sufficient.
• Requires battery storage to ensure power supply during night or bad weather.
• Can operate without solar panels, using the grid or generator to charge the batteries.

 

4. Components and Working Principle of Hybrid (On/Off-Grid with Storage) Solar Photovoltaic Systems

A hybrid PV system typically includes:

 

• PV panels
• Hybrid inverter (supports both on-grid and off-grid modes)
• Battery storage
• Electrical loads
• Advanced solutions now integrate the hybrid inverter and battery into a single unit for greater convenience and performance.

 

Hybrid systems are ideal for:

• Areas with frequent power outages
• Places where surplus solar energy cannot be exported to the grid
• Situations where self-consumption electricity prices are higher than feed-in tariffs
• Scenarios with time-of-use electricity pricing, where peak electricity is expensive

 

Working Principle:

During daylight hours, solar energy is used to directly power local loads through the hybrid inverter. Any excess electricity is stored in the battery.

 

At night, the system discharges the stored energy to supply loads. Users can also schedule charging and discharging times to take advantage of lower off-peak electricity rates.

 

When a grid outage occurs, the system automatically switches to off-grid mode, ensuring uninterrupted power supply.

 

Key Features:

• Combines the benefits of both on-grid and off-grid systems: grid-tied operation with backup during blackouts
• Requires battery to function in off-grid scenarios
• Can operate without PV panels, using grid power to charge batteries for peak shaving or backup power

 

5. Components and Working Principle of Microgrid Systems

A microgrid is a localized power network composed of:

 

• Distributed energy sources (e.g., solar, wind, diesel generators)
• Loads (residential, commercial, industrial)
• Energy storage systems
• Centralized control and management system

 

 

Microgrids convert distributed energy into usable electricity close to the point of consumption, increasing efficiency and reducing transmission losses.

 

Microgrid systems are intelligent, autonomous networks capable of self-control, protection, and energy management.

 

They can operate either connected to the main grid or in island (off-grid) mode, solving the challenge of integrating distributed and renewable energy sources at scale.

 

They represent the future of active, intelligent power distribution, especially where a variety of energy sources and loads need to be managed efficiently.

 

Summary Table: Comparison of Four PV System Types

System Type	Grid Dependency	Energy Storage	Operational Flexibility	Cost	Typical Applications
On-Grid	Fully dependent	Not required	Low	Lowest	Urban households, commercial buildings
Off-Grid	Fully independent	Required	Medium	High	Remote areas without grid access
Hybrid (On/Off-Grid)	Switchable	Required	High	Medium-High	Areas with unstable grid or high tariffs
Microgrid	Optional	Usually included	Very High	Highest	Industrial parks, remote communities

 

Summary

This article provides a comprehensive overview of the four main types of Solar Photovoltaic Systems-On-Grid, Off-Grid, Hybrid, and Microgrid. It begins by explaining the core technology behind solar PV: the photovoltaic effect, which directly converts sunlight into electricity without relying on thermal processes.

 

Each system type is explained in terms of key components, working principles, and typical applications, helping readers choose the right solution based on power needs, grid reliability, and energy management goals.