Solar solutions come in a range of different configurations. One important distinction to be aware of is the difference between AC solar and DC solar. We install both versions, and in our solar design process we help you to understand the benefits of these solutions for your own energy requirements. In this article, we take a look at the difference between these two approaches to solar.
Solar – A Broad Overview
In a typical residential solar installation, solar panels convert the sun’s energy into DC (Direct Current) electricity. However, before this electricity can be used in the home, it needs to be converted to AC (Alternating Current). It is the different way that this conversion process is approached that defines the difference between AC and DC solar systems.
How AC Solar Works
DC solar is arranged in a ‘series’ circuit – connected panel to panel, this circuit leads electricity as DC to a single inverter inside the home, where it is transformed into AC power.
AC Solar works in a different way. Each solar cell has a microinverter which converts DC to AC at the solar cell. This significant distinction opens up a wide range of benefits in safety and capability:
Benefits of AC Solar Solutions
1. Avoiding High Voltages on the Rooftop
In a DC Solar system, the series circuit can lead to high DC voltages on the rooftop. This is due to the fact that the solar cells are linked together in series. This can result in DC voltages of up to 600 (Residential) – 1000 (Commercial) Volts DC on the roof.
In the event of the circuit being compromised due to any number of reasons (rodents, environmental wear and tear, water ingress, etc) this can result in high voltages of DC current arcing which can cause injury and fire.
An AC solar system doesn’t need high DC voltages – its DC voltages never exceed 80 volts. This makes for a safer solution.
3. No Need for a DC Isolator Switch
The DC Isolator switch is one of the most common points of failure in a DC Solar system. The purpose of this switch is to separate the DC circuit from the rest of the house. Although the intention is to make the system safer, over time the failure of these switches and subsequent exposure to the environment is a leading cause of failure in DC solar systems.
In an AC solar solution, there is no need for a DC isolator switch because there is no high-voltage DC circuit. Microinverters transform DC to AC at each panel, and the AC voltage on the rooftop is much lower because it is operating on a per-panel basis, as opposed to the combined effect in a DC Solar series circuit.
4. Performance in Partial Shading
In a DC solar installation the performance of the whole system depends on the performance of each individual cell. If a cell is shaded, this impacts the performance of the entire array, reducing the output. In an AC solar system, cells work separately from each other. Any shading only impacts the individual cell, not the entire system.
4. Centralised VS Decentralised Inversion
Another important distinction between AC and DC solar is the impact of a single vs multiple inversion points. In a DC solar system, the whole system relies on a single inverter to transform DC to AC. If this inverter fails, the whole system goes down. This single point of failure doesn’t exist in an AC solar solution. Here, the inversion happens at the panel with a microinverter. If it should fail, only a single panel is impacted – the rest of the system won’t be affected. This creates a more robust system that isn’t dependent on a single inverter.
5. Scalability
Scalability (the ability to change the size) of your solar installation is an important consideration. The installation that works for you now may not work for you in 5 years time. A case in point is electric vehicles. If you transition to an electric vehicle, the need to charge your car would change the profile of your energy usage requirement.
DC solar installations are inherently less scalable than AC solar installations. Adding additional solar panels is only possible as long as the single inverter can handle the additions. It may be necessary to upgrade your inverter to accommodate extra panels. In comparison, AC solar can be scaled as needed. Panels can be added, or removed, as required without compromising the rest of the process. This is achieved by microinverters transforming DC to AC at the cell rather than at a single inversion point.
Learn More About Solar Solutions
If you’re interested in learning more about solar solutions or getting a quote, please contact our team. We service Noosa and surrounding suburbs.
