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Optimised solar PV outperforms string inverters

Blog
DES Energy
11 Nov 2025

As organisations increasingly turn to solar energy to reduce costs and carbon emissions, choosing the right type of solar photovoltaic (PV) system becomes crucial. One of the most important decisions is whether to install a traditional string inverter system or an optimised system. While both convert sunlight into usable electricity, they differ significantly in how they manage performance, safety, and long-term value.

If your organisation is considering solar energy procurement, understanding the difference between optimised solar PV systems and traditional string inverters is essential.

What is a String Inverter System?

A string system connects multiple solar panels in a series - like fairy lights on a single wire. These panels feed into one central inverter, which converts the electricity from direct current (DC) to alternating current (AC) for use in buildings.

The drawback is that if one panel under performs, due to shade, dirt, or a fault, it drags down the performance of the entire string. Think of it like a row of cyclists: if one slows down, everyone behind them does too.

What are Optimised Solar PV Systems?

An optimised system uses small devices called power optimisers attached to each panel. These allow each panel to work independently, so if one is shaded or dirty, the others continue performing at full capacity.

In simple terms: each panel is its own cyclist, free to go at its own pace. This independence leads to better energy output and easier fault detection.

A leading example of this technology is SolarEdge, widely recognised for panel-level optimisation and advanced safety features such as rapid shutdown. This makes it a popular choice for organisations seeking compliance and efficiency under frameworks.

SolarEdge Optimised vs String Inverter: Key differences explained

Below, we compare optimised systems vs string inverter systems to help you choose the right solution for your organisation’s needs under the Civil Engineering Works and Services Framework:

Solar PV systems comparison table

Why it matters

Efficiency and Output

Optimised systems typically produced 10-20% more energy over their lifetime. This is especially important for buildings with complex roof shapes or partial shading, common in schools, hospitals and commercial estates.

Safety

Traditional string systems carry high DC voltage across long cables, which can pose fire risks. Optimised systems can often include rapid shutdown features, reducing voltage in emergencies and improving safety for maintenance teams and first responders.

Maintenance and Monitoring

With string systems, identifying a fault means checking the whole array. Optimised systems offer panel-level monitoring, making it easier to spot and fix problems quickly, saving time and money.

Future-proofing

Optimised systems are more adaptable. They integrate easily with battery storage and electric vehicle (EV) charging infrastructure, supporting long-term sustainability goals.

Questions to ask when choosing a solar PV supplier

To ensure you’re selecting the right system and installer, consider asking:

• Is the system an optimised solar PV system, or string inverter system?
• Does the system include rapid shutdown or other safety features? Does it interact with your fire alarm?
• Can the panels be monitored individually?
• Is the system compatible with future upgrades like battery storage or EV charging?
• What warranties and support are offered?
• Does the supplier offer solutions compliant with the YPO solar framework?
• Does the system meet UK safety standards and guidance?

Food for thought

While string systems may appear cheaper upfront, they often come with hidden costs (lower energy yield, higher maintenance, and increased safety risks). Optimised systems offer better performance, safety, and long-term value, making them a smarter choice for organisations committed to sustainability and operational efficiency.

As a NICEIC accredited, SolarEdge certified installer, DES energy optimised solar PV systems align with YPO’s renewable energy procurement standards. Whether you’re comparing SolarEdge vs string inverter options or seeking guidance, our technical experts can help.

To learn more, visit the desenergy.co.uk or explore procurement options through the Civil Engineering Works and Services Framework. Our team is ready to support your organisation’s sustainability journey.

Author

DES Energy

01253 881 220

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