How does a photovoltaic system work and what types of systems are there?
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With the growing demand for environmentally friendly and cost-saving energy solutions, many are wondering exactly how a photovoltaic (PV) system works and what options are available on the market. In this post, we'll take a look at how solar energy is converted into electricity and how different systems differ from one another to help you find the best solution for your energy needs.
How does a photovoltaic system work?
A photovoltaic system converts sunlight directly into electrical current. The heart of every PV system is the solar module, which consists of many small solar cells. These cells are usually made of silicon, a semiconductor material that reacts to sunlight and thereby generates electrical voltage.
The process in detail:
- Sunlight hits the solar cells : When light hits the solar cells, the energy of the light particles (photons) is transferred to the electrons in the silicon.
- Electricity generation through the photovoltaic effect : This energy sets the electrons in motion, creating an electric field. This process is called the photovoltaic effect.
- Direct current is generated : The generated voltage is discharged as direct current (DC).
- Inverter converts the power : Since households use alternating current (AC), an inverter converts the direct current from the modules into usable alternating current.
- Electricity use or feed-in : The electricity generated can either be used directly in the household, temporarily stored in a battery storage system or fed into the electricity grid, where it is remunerated.
The most important components of a PV system:
- Solar modules : These capture sunlight and generate electricity.
- Inverter : Converts direct current into alternating current.
- Mounting system : Used to attach the modules to the roof or other surfaces.
- Battery storage (optional): Stores excess power for later use.
- Smart Meter : Measures electricity consumption and electricity fed into the grid.
Different types of PV systems
There are different types of PV systems, tailored to different needs and circumstances. The most important systems are grid-connected, off-grid, and hybrid PV systems.
1. Grid-connected PV system (on-grid)
What is that?
A grid-connected PV system is directly connected to the public power grid. The generated electricity is either used immediately in the household or fed into the grid. Any unused electricity is remunerated by the energy supplier.
Advantages
- Cost savings through feed-in tariffs : Grid-connected systems benefit from the feed-in tariff paid for electricity fed into the grid.
- High cost efficiency : Since no battery storage is required, these systems are cheaper to purchase and maintain.
- Reliability : If needed, additional power can be drawn from the grid when solar production is insufficient.
Disadvantages
- Dependence on the grid : If the power grid fails, the PV system also switches off.
- Limited self-sufficiency : Since there is no storage, unused electricity can only be fed into the grid and not stored for later use.
2. Off-grid PV system
What is that?
An off-grid PV system is not connected to the utility grid and is suitable for remote locations or homes that are intended to be completely self-sufficient. Battery storage is essential here to store electricity for periods without sunlight.
Advantages
- Independence : Off-grid systems are completely self-sufficient and are suitable for remote locations such as mountain huts or holiday homes.
- Maximum self-sufficiency : The electricity generated is used entirely by the owner, without dependence on an energy supplier.
Disadvantages
- High initial investment : Since a powerful battery storage system and often an emergency power generator are required, the purchase is more expensive.
- Storage requirements : The battery storage capacity must be sufficient to bridge longer periods without sunlight, which can further increase costs.
3. Hybrid PV system
What is that?
A hybrid PV system combines the advantages of grid-connected and off-grid systems. It is connected to the utility grid but also has a battery storage system. This allows excess electricity to be stored and used when needed, rather than being fed into the grid.
Advantages
- High self-consumption rate : Since the electricity is initially used and stored in your own household, a large part of the demand can be covered by your own system.
- Flexibility : In the event of a power failure, the stored power from the battery can be used, providing additional security of supply.
- Cost optimization : When grid electricity prices are low, you can get electricity from the grid and use your own electricity when your own consumption is high.
Disadvantages
- Higher acquisition costs : The combination of inverter and battery storage increases the costs.
- Complex planning : The optimal use of the storage system requires careful planning and dimensioning.
Which PV system is right for me?
Choosing the right system depends on your individual needs and location. Here's a little help to help you decide:
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For households with a grid connection and low self-consumption, a grid-connected system without storage is best suited. This allows you to benefit from the feed-in tariff and reduce your electricity costs without high additional costs.
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For households with high self-consumption and a desire for greater independence, a hybrid system is a good choice. The battery enables extensive use of the home's solar power and increases supply security.
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For locations without a grid connection or where complete independence is desired, an off-grid system is the optimal solution. However, please note that a standalone power supply requires a higher investment.