Solar Panel Inverters: What are they & How do they work?

Learn what solar panel inverters are, how they work, and which solar inverter is best for you.

Toby
February 14, 2024
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At the heart of a solar energy system lies a key player that operates behind the scenes but is vital to the process – the solar panel inverter. 

In this article, we'll explore what solar panel inverters are, how they work, and the different types available. 

What is a Solar Panel Inverter?

A solar panel inverter is a device that takes the direct current (DC) electricity generated by solar panels and transforms it into the alternating current (AC) electricity that powers your home. In essence, it acts as a bridge, converting the electricity into a usable form.

Think of it as the conductor of an orchestra. While solar panels produce DC electricity from the sun's rays, most household appliances and the power grid rely on AC electricity. The inverter harmonises these two types, ensuring your home can utilise the clean, renewable energy harnessed from the sun.

Solar Optimisers Explained

Solar Optimisers are often used in conjunction with solar inverters. They are small components that can be connected to each solar panel in your system. Their primary role is to ensure that each panel operates at its peak efficiency, regardless of the varying levels of shade or sunlight exposure they might encounter throughout the day.

Whilst we only need to know the above to understand solar inverters better, you can dive into our article on what are solar optimisers for an in-depth breakdown.

How Do Solar Panel Inverters Work?

With an understanding of what solar panel inverters and optimisers are, it's time to delve into how solar inverters work. 

Solar inverters ensure that the electricity produced by your solar panels is compatible with your home's electrical system. Here's a simplified breakdown of how this conversion process unfolds:

1. DC to AC Conversion: The solar inverter takes the DC power generated by your solar panels and converts it into AC power. This process involves changing the electrical current's direction, creating a waveform that is similar to the electricity supplied by utility companies.

2. Stable Voltage and Frequency: In addition to converting the current type, the inverter stabilises the voltage and frequency of the electricity. This ensures that the power supplied to your home is consistent and reliable.

3. Synchronisation with the Grid: For grid-connected solar systems, the inverter synchronises the solar-generated electricity with the electrical grid. This allows excess power to be fed back into the grid as part of the smart export guarantee

Maximum Power Point Tracking (MPPT)

Another critical feature of many solar inverters is Maximum Power Point Tracking (MPPT). MPPT is a technology that helps optimise the energy output of your solar panels. 

Solar panels operate at their peak efficiency when they receive direct sunlight. However, real-world conditions are rarely ideal, and factors like shade, cloud cover, or panel temperature variations can impact the panel's performance.

Recommended Article - Do Solar Panels Need to be In Direct Sunlight?

MPPT is designed to overcome these limitations by continuously monitoring and adjusting the voltage and current to ensure each panel operates at its maximum power point, even when conditions are suboptimal. In other words, it ensures that your panels generate as much electricity as possible, maximising your system's overall energy production.

Types of Solar Panel Inverters

When selecting a solar panel inverter for your residential solar system, it's crucial to consider the different types available. Each type offers distinct features and benefits, allowing you to tailor your choice to your specific needs and circumstances. 

Note: We won't delve into central inverters, as they are typically used in large-scale solar installations and not meant for residential use.

String Inverters

String inverters connect multiple solar panels in series, forming a string. All panels within a single string are typically at the same height and orientation. This configuration ensures uniformity in electrical characteristics. 

String inverters usually have connections for multiple strings, allowing you to have panels on different sides of the house without the need for optimisers. This makes them perfect for east/west-facing roofs, where the panels receive sunlight at different times of the day.

Pros:

Cost-Effective: String inverters are usually more budget-friendly compared to other inverter types.

Reduced Efficiency: If one panel on a string underperforms due to shading or a fault, it can affect the entire string's performance.

Easy Maintenance: Simplified design makes them easy to maintain and repair.

Cons:

Design Limitations: May not be suitable for installations where panels have varying orientations and heights, or face different directions. However, this can be worked around if there are enough connections on the inverter.

Proven Technology: They are a popular choice for residential use, with a history of reliable performance.

Microinverters

Microinverters offer a unique approach by providing each solar panel with an inverter. These inverters sit directly under the panels and convert the electricity there. With our microinverter systems there’s no need for a main inverter elsewhere in the property. 

In this setup, every panel operates independently, which means that if shading or a fault occurs on one panel, it doesn't affect the others. This design can enhance your solar panels' energy production by 5-30% compared to string inverters, but it typically comes at a higher cost.

Pros:

Optimised Performance: Each panel operates at its maximum capacity, even if other panels are shaded or underperforming.

Easy Installation: Microinverters simplify the installation process as there is no need to string panels together.

Monitoring Capabilities: Microinverters often come with advanced monitoring systems that allow you to track the performance of each panel.

Cons:

Maintenance Complexity: As there are more individual components, potential maintenance could be more intricate.

Higher Cost: Microinverters are typically more expensive than string inverters due to their advanced technology.

Power Optimisers

Power optimisers are devices that are installed behind each solar panel in a system using a string inverter. They serve the function of optimising the electrical output of each panel. Much like microinverters, power optimisers prevent shading or fault issues on one panel from affecting the performance of the entire string. Without them, one shaded panel would bring the other panels down to its level, dramatically decreasing your energy production.

Pros:

Enhanced Efficiency: Power optimisers can improve the energy production of your solar panels by mitigating issues that affect a single panel's output.

Flexible Design: They offer greater flexibility in terms of panel placement, allowing you to harness energy even if panels face varying directions.

Cons:

Higher Cost: Like microinverters, power optimisers come at an additional cost compared to string inverters.

Hybrid Inverters

Hybrid inverters are essentially just string inverters that are also compatible with batteries. Thus allowing your system to store excess solar energy. 

Hybrid inverters can intelligently manage the flow of the electricity generated by your solar panels, directing it to where it’s needed most; whether it’s powering your home, charging the battery, or exporting to the grid. 

Enhanced Efficiency: Hybrid inverters combine the benefits of both string and micro-inverters, offering improved energy production and performance optimisation.

Moderate Cost: While more budget-friendly than microinverters, hybrid inverters can be costlier than traditional string inverters.

Cost-Efficiency: They strike a balance between microinverters' higher cost and the lower cost of string inverters.

Compatibility Check: Like power optimisers, compatibility with your central inverter is a crucial consideration.

Do I need Inverters for my solar panels?

Without a solar panel inverter, the energy produced by your solar panels would be unsuitable for powering your home. So, whether you opt for string inverters, microinverters, power optimisers, or hybrid inverters, these devices are essential for transforming solar energy into a usable power source. 

How much does a solar inverter cost in the UK?

The cost of a solar inverter in the UK can vary significantly depending on several factors, including the type of inverter you choose, your specific energy needs, and the quality of the inverter. Here's a general overview of the price range for different types of solar inverters:

String Inverters - Prices typically range from £500 to £1500, making them one of the more budget-friendly options.

Microinverters - On average, microinverters cost between £150 and £200 each. For a system with 10 panels, you might be looking at a total cost of £1500 to £2000

Power Optimisers -  Power optimisers typically cost about £50 each each but require a string inverter as well. 

Hybrid Inverters - The cost of hybrid inverters can range from £1200 to £1500.

The right choice of inverter can make a significant difference in the efficiency and performance of your solar panel system, leading to greater energy savings and potentially a faster return on your investment.

Which solar inverter is right for you?

For personalised recommendations on the best solar inverter and panels for your specific needs, consider using our solar panel tool. This tool takes into account your location, energy goals, and budget, to provide tailored suggestions to help you harness the full potential of solar energy.

Or if you’d prefer to do it yourself, here's a quick guide to help you make an informed decision:

1. System Size and Configuration - Consider the size and configuration of your solar panel system. Larger systems may benefit from microinverters or hybrid inverters, while smaller systems can work well with string inverters.

2. Budget Considerations - Your budget plays a significant role in your inverter choice. String inverters are typically the most cost-effective, while microinverters and hybrid inverters come at a higher price point. 

3. Efficiency and Performance - Assess the efficiency and performance of the inverter type. Microinverters and hybrid inverters are known for their efficiency, especially in scenarios with shading or panel faults.

4. Maintenance Requirements - Consider the maintenance needs of different inverter types. While string inverters are relatively low-maintenance, microinverters and optimisers may require more attention over time.

Final Thoughts

Solar panel inverters are the unsung heroes of your solar energy system. By making informed decisions about your solar inverter, you can optimise your solar panel energy production, save on costs, and contribute to a greener future.

We offer a solar panel tool that simplifies the process of choosing the right inverter and panels for your specific needs. Simply answer some questions about your property and energy use, and our tool will run the numbers, providing you with an in-depth breakdown of your potential investment. 
Consider also checking out the rest of our green guides. Our comprehensive solar panel guide may be of interest, or perhaps our guide on whether solar panels are worth it in 2024.

Recommended Guides:

- How many solar panels can i fit on my roof?

- Do solar panels need to be in direct sunlight?

- Are solar panels worth it in the uk?

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