Solar

Noosa Electric Co installs Advanced On-Grid AC Solar Solutions in Noosa and surrounding suburbs. On this page, we clarify the difference between On-Grid, Off-Grid and Hybrid Solar solutions.

Relationship to the Grid

Solar installations can be configured to work in different ways with the public electricity grid. Generally, they fall into one of the following three categories:

• On-Grid
• Off-Grid
• Hybrid

These distinctions explain how the solar energy is used. Explanations follow:

Our Solar Solutions
We provide On-Grid solar solutions which utilise advanced AC Solar technology.

Noosa Electric Co provides an Advanced On-Grid AC Solar Solution suitable for Australian homes and businesses. We service Noosa and surrounding suburbs. On this page, we provide information to help you understand how AC solar works and how it is different from other solar approaches.

Solar – A Broad Overview

In a typical residential solar installation, the sun’s energy is converted into electricity. This is done by solar panels using the (PV) effect. Panels convert solar energy into DC (direct current) electricity. This is then converted to AC (alternating current) for practical use. While all of this can be done with a DC or an AC solar system, they go about it in different ways.

DC and AC Solar Differences

1. Type of Circuit

DC solar arranged in a ‘series’ circuit has all electrons flowing through the same circuit. Connected panel to panel, this circuit leads electricity as DC to a single inverter, where it is transformed into AC suitable for use inside the home.

An AC Solar installation works in a different way. Each solar cell has a micoinverter which converts DC to AC at the solar cell. By working with AC and enabling the solar cells to operate individually, a range of advantages are unlocked in safety, efficiency, scalability and longevity.

2. 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. According to the Safer Solar website, two fires caused by DC-related faults in solar power systems are reported per week in Australia, and this number can be expected to rise as the rate of installations increase and systems age. 

An AC solar system doesn’t need high DC voltages – its DC voltages never exceed 80 volts. This makes for a safer solution.

3. DC Isolator Switch

The DC Isolator switch is one of the most common points of failure in a DC Solar system. Required by law in Australia, 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.

A Solar installation represents a significant investment. Accordingly, it’s important to prioritise a quality solution. Make sure your solar will go the distance with a Noosa Electric Co Advanced On-Grid AC Solar solution. We use high-quality components backed by a warranty, giving you peace of mind over your solar installation. On this page, we examine how our AC Solar solution is geared to take your home or business all the way into the future.

Quality Components

Using quality components in conjunction with a professional installation is the best way to avoid a solar headache. Shortcuts in quality create short-term solutions, and as with all things electrical, breaking down might be a best case scenario. Fires and injuries can also result from poor quality components or inadequate installation practices.

We use high quality components in our AC Solar solutions including Hyundai PV cells & Enphase Microinverters, designed and equipped for harsh Australian conditions. Our AC Solar is designed to go the distance.

Professional Installation

Noosa Electric Co has serviced the Sunshine Coast since 1973. We have a reputation for quality, and ensure our installations in appliances, air-conditioning, refrigeration, electrical and solar a conducted in a compliant and professional manner.

Longevity By Design

AC solar systems have inherent advantages that set the up for a long and successful life. Unlike DC systems, there are no high voltages on the rooftop and no need for a DC isolator switch (a common cause of system failure). Because the inversion process is handled on a per-panel basis (rather than relying on a single inverter) any inverter failure only impacts a single panel – not the whole system.

Scalability (changing the size of your solar system) is an important consideration in a solar installation. After all, the system that works for you now may not cut it in 5 years time. Noosa Electric Co provides an Advanced On-Grid AC Solar Solution which brings new capabilities to residential and commercial solar. On this page, we examine how AC Solar creates a more scalable solution than DC Solar, ensuring your installation can adapt to suit your changing needs in the future.

The Need For Solar Scalability

We live in an era of change and adaptation. While it isn’t always easy to see what the future will bring, it can be certain that it will bring more change! For example, in 5 years time you may have an electric car, (or two) in the garage that need to be charged every day. That’s why factoring scalability into your installation is important.

How Is Solar Scaled Up?

To increase the power generated by your solar system, either more panels need to be added or existing panels need to be replaced with more efficient panels. Either way, the goal is to increase the solar energy being converted to electricity.

The Problem with Scaling DC Solar

In a DC installation, the conversion from DC to AC is done at a single, central inverter. Adding more panels to your system will increase the DC voltage going to your inverter. A disadvantage of this approach is that the capacity of the system is limited to the capacity of the inverter: a new inverter may be required to handle the addition of more panels to your system.

Scaling With AC Solar

AC solar works differently. The inversion process is accomplished at each individual panel, meaning that panels can be added to the system as required without jeopardising the ability of the system to handle the added power – the system does not rely on the capacity of a a centralised inverter. Another advantage of AC Solar is the minimum panel requirement. DC systems require a minimum of 8 panels, whereas AC systems don’t have a minimum. The configuration can be scaled to suit your needs, however big or small they may be.

An investment in solar technology should always have the goal of achieving maximum efficiency. Noosa Electric Co provides an Advanced On-Grid AC Solar Solutions, an alternative to traditional DC solar in a string configuration, with advantages in safety, efficiency, longevity and scalability.

On this page, we examine how AC solar creates a more efficient solution, maximising the return on your solar investment with a system calibrated to get results.

AC Solar Efficiency Advantages

AC Solar has two major advantages over DC solar in operational efficiency. These are:

1. Individual Panel Performance
2. No Single Inverter (Point of Failure)

Individual Panel Performance

A fundamental distinction between AC and DC solar systems is the in the way they deal with the conversion from DC to AC current. In a DC solar system, the conversion process occurs at a single central inverter, whereas an AC solar system converts DC to AC at each individual panel. This creates an efficiency advantage.

In a DC Solar installation in series, for the entire array to perform optimally, all of the panels in the configuration must be performing optimally. If any panel reduces its output (for example due to shade) the performance of the whole system is reduced accordingly.

A single quarter-shaded panel is actually a quarter shaded system. (SRC: Enphase)

With an AC Solar system, panels operate on an individual basis. The total performance does not rely on the performance of all of the other panels. If a panel goes into shade, only that individual panel’s performance is compromised – not the entire system.

No Single Inverter (Point of Failure)

Performance requires reliability, and a significant advantage of AC solar over DC solar is its evolution beyond using a single inverter. In the case of using a single inverter, the failure of that component will cause the entire system to fail. AC solar works differently. With AC solar, the conversion from DC to AC is done on each individual panel. Accordingly, an inverter failure only affects a single panel – not the entire system.

With any electrical installation, safety is always the highest priority. Our advanced AC solar solution comes with a range of advantages over DC solar in a string configuration, and improved safety is one of them. On this page, we look at the two main ways that this is achieved.

A fundamental difference between AC solar and DC solar in a string configuration is how they transform DC to AC:

DC solar: transforms DC to AC at a single inverter
AC solar: transforms DC to AC at each panel

You can read more about this process here. What’s important is that with AC solar, it does away with two disadvantages of the DC string system:

1. No high voltage DC on the rooftop
2. No need for a DC isolator switch

High DC Voltage on the Rooftop

In a DC series circuit, each panel added to the system increases the voltage of the circuit. This creates high voltages of up to 600 (residential) – 1000 (commercial) volts on the rooftop. High voltages in conjunction with any type of compromise in the circuit are dangerous and can lead to DC arcing, fire and injury.

According to the Safer Solar website, two fires caused by DC-related faults in solar power systems are reported per week in Australia, and this number can be expected to rise as the rate of installations increase and systems age. 

There are many reasons why an installation may fail:

• Loose joints due to poor installation
• Loose joints due to poor quality connections
• Corrosion of joints over time
• Insulation degradation over time due to UV exposure
• Insulation cracking over time due to changes in temperature (hot – cold)
• Degradation of insulation due to aging
• Damage to insulation by rodents, insects, birds
• Damage to insulation during installation
• Damage to insulation by future building works
• Water ingress to cables, conduits.
• Water ingress to DC isolators from poor installation
• Water ingress to DC isolators due to degradation of seals over time
• Water ingress to inverter
• Water ingress to solar module or junction box

(SRC: AC Solar Warehouse)

AC Solar – A Low Voltage Solution

In a DC solar series circuit, each panel added to the system increases the voltage of the circuit. AC solar works differently. Instead of carrying high-voltage DC to a central inverter, AC solar microinverters work on a per-panel basis, producing a low individual voltage of between 48-60V, even less than the voltage of an electrical fan. With no high voltages on the rooftop, a safer solution is created. (SRC: Enphase)

DC Isolator Switch Failure

In Australia, in a DC solar installation, a DC isolator switch is required by law between the solar panels and the inverter. Its purpose is to switch off DC current if necessary for safety reasons. Unfortunately, the DC isolator switch is a common point of failure. Failure of this component may result in DC arcing, which may cause injury or fire.

In an AC Solar system, there is no need for a DC isolator switch. Because the transformation from DC to AC is done at the panel, a DC isolator switch isn’t required. By removing the need for this switch, a simpler, safer solar solution is created.