As more public sector operators turn to solar to provide clean, low-cost energy for their buildings, many energy managers are finding their roles extended to managing what’s on the roof as well as inside the building. For those new to solar, this shift may feel daunting. However, help is at hand. Here, Christelle Barnes, UK Country Manager at SolarEdge Technologies, discusses recent advancements in solar technology that help to optimise energy production, reduce O&M costs, and make solar even safer.
What are the top priorities for individuals charged with responsibility for a solar installation?
As the deployment of PV (photovoltaic) solar systems accelerates and existing systems mature, PV installations are being viewed as more than just a source of clean energy. Instead, they are regarded as long-term investments that need to be closely managed in order to improve their ROI and bottom line. As with any investment, the two main ways to improve the ROI of a PV system is to increase the revenue it provides and decrease the lifetime cost of ownership.
One of the first steps to increase PV system production happens during the design process. It’s important to select a system that can meet both the site’s current and future energy needs. For example, if electric vehicle (EV) charging stations are planned, they will increase the site’s electricity demand. This should be considered during design to ensure the system can handle future needs.
Advancements in solar technology, such as more efficient solar panel materials, are making it possible to pull more power from even the most challenging roof spaces. Even more important are advancements in solar inverters. Although they account for less than 10% of solar system costs, inverters are responsible for 100% of energy generation. Therefore, choosing the right inverter has significant implications for the system’s long-term financial performance.
In a traditional inverter system, the inverter has two main functions: converting DC electricity from solar panels into AC electricity for buildings and performing maximum power point tracking (MPPT) to extract maximum power from the system. Since MPPT is the most expensive component of an inverter system, it’s common to connect as many panels as possible to each MPPT. While this may save money initially, it creates inefficiency, leading to higher long-term costs.
This is because of the energy mismatch that occurs when panels operate at different efficiencies. There are many factors that can impact panel performance, including ageing, soiling, or shading from clouds, trees or nearby buildings. In traditional inverter systems, panels are wired in series, so if one panel’s output is low, the efficiency of all connected panels is reduced, significantly lowering overall energy production.
Additionally, traditional inverter systems also require panels to be placed in identical string lengths and at the same pitch and orientation. This can limit the number of panels that can be installed and potentially make solar financially unviable.
Due to these and other limitations, there has been a notable shift from traditional string inverters to more advanced DC-optimised systems. In a DC-optimized system, Power Optimizers are installed on each pair of panels to monitor and optimize performance at the panel level, rather than the string level. This ensures that if one panel’s performance drops, only that panel is affected. Further, DC-optimized systems also provide more design flexibility, enabling larger installations on rooftops with limited space.
Q: What are the most effective maintenance strategies to help decrease PV system lifetime costs?
The most common O&M strategies for PV systems are preventative and corrective maintenance. Preventative maintenance aims to keep the system in optimal condition and minimise downtime, typically requiring an annual site visit to evaluate components and check system health. Standard inverter systems necessitate inspecting each panel to ensure proper function, which can be costly, inefficient, and dangerous for personnel working at heights and with high voltages. During preventative maintenance, latent issues may be discovered that have led to decreased energy production, triggering the need for corrective maintenance.
DC-optimised technology introduces a third option: reactive maintenance. In a DC-optimised system, Power Optimizers monitor each panel pair’s performance in real-time and send pinpointed alerts about system issues, reducing the need for site visits. This allows maintenance teams to analyse and troubleshoot remotely. For example, if a panel has a failed diode, an alert is sent to personnel, who can quickly identify the panel and provide a screenshot for a warranty claim. This way, during the next site visit, the team can replace the failed panel, instead of only learning about its existence.
What can be done to ensure solar systems are safe – and remain safe?
With millions of systems installed worldwide, solar is proven to be safe and reliable. However, as traditional solar installations can reach voltages as high as 1,500VDC, precautions should be taken to ensure the safety of people and assets.
There are two key safety features to consider when selecting solar technology. The first is the safe-DC feature, which minimises the risk of electrocution during installation, maintenance, or in the event of a fire. In traditional inverter systems, shutting down the inverter or grid connection stops the current flow, but DC voltage in the string cables remains live while the sun is shining. Safe-DC addresses this by automatically lowering the output voltage of each panel to a touch-safe 1V.
The second feature is arc fault detection. While rare, electrical arcs can be triggered by issues like loose connections. The U.S. has strict regulations for arc fault detection, and while the UK has not yet introduced similar requirements, this is expected to change. So, it’s important not to get caught out.
For more information, visit: www.solaredge.com/uk.
This article appeared in the May 2025 issue of Energy Manager magazine. Subscribe here.