What is Solar Shading and Why Does it Matter?
Solar shading refers to any obstruction—be it trees, chimneys, neighbouring buildings, or even bird droppings or dirt—that blocks direct sunlight from reaching rooftop solar panels. This matters because the performance of solar PV arrays relies on uninterrupted solar irradiance; even light shade can significantly reduce the power output. In some scenarios, experts estimate system losses up to 40%, especially when panels are wired together in series and one panel in a string is shaded.
How Does Shading Affect Solar Panel Output?
Shading impact depends on its duration, intensity, and the technology used. Even moderate shade from leaves or dirt can lead to decreases, but solid or partial shading can result in output drops above 80% for those panels. Of note for UK homeowners is that in series-wired PV strings, the weakest-performing (shaded) panel dictates the power output for all connected panels, drastically reducing system efficiency.
Monocrystalline panels typically handle light shading better thanks to built-in bypass diodes, but microinverters and optimisers offer far greater strides in shade management.
For tailored shade assessment and system design to maximise output, speak with THE Atlantic Renewables engineers.
Can Solar Panels Work if Partially Shaded?
Modern panels can operate with partial shade, but some sections will lose output due to bypass diode technology. This means shaded sections stop producing power, while the rest of the panel continues operating. Over time, however, regular partial shading causes ‘hotspots’—areas of overheating—that shorten panel lifespan and in extreme cases can result in damage or even fire risk.
Studies show partial shade not only reduces output but can cause temperature spikes of 80°C or more. Ensuring panels are installed with enough bypass diodes mitigates both the output loss and heat risks for most home arrays.
What Solutions Exist for Roofs with Frequent Shading?
There are several proven solutions for shaded roofs:
- Power Optimisers: Attach to affected panels, allowing control and maximising performance even during partial shade.
- Microinverters: Each panel operates independently, so unshaded panels remain at maximum output regardless of others.
- Group panels by exposure: Design the array so that shaded and unshaded modules are in separate strings. This maximises generation from unshaded arrays.
- Modern Inverters with Shade Optimisation: Brands like Fronius, SMA, and Goodwe deploy MPPT algorithms that actively seek the best power point under shading.
- Panel relocation or adjustment: Rearranging panels or using east/west orientations can retain 80-90% system efficacy in UK homes.
Is it Worth Installing Solar PV in Shaded Conditions?
Despite potential output losses, professional design and modern technology mean solar investment is still worthwhile for many UK properties. Using microinverters or optimisers, as well as annual maintenance and strategic orientation, can offset shade and make systems viable in less-than-perfect conditions.
High-grade panels and professional installation by Atlantic Renewables experts ensure maximum output and system longevity—even on challenging rooftops. A system designed with site-specific shading analysis can generate substantial savings and emissions reductions.
What Risks Are Associated With Shaded Solar Panels?
Major risks include:
- Hotspots: Small areas of overheating that can damage cells, reduce lifespan, and pose fire hazards.
- Permanent panel damage: Years of regular shade can accelerate bypass diode failure, leading to glass breakage or electrical faults.
- Significant lifetime output loss: Hotspots and electrical stress create losses of 15% or more in affected panels over their useful life.
Regular maintenance, periodic cleaning, and preventative installation upgrades (like bird proofing) considerably reduce these risks.
How Can Solar Installers Like Atlantic Renewables Manage Shading?
Expert solar installers carry out detailed on-site assessments, factoring in sun paths, obstacle mapping, and annual shading analysis. They may use shade-tolerant technologies and custom site design to guarantee optimal placement, string configuration, and inverter choice—including microinverters for heavy shade.
Panel cleaning, strategic maintenance, and ongoing support complete the solution, safeguarding customer performance and return on investment.
- Shading can cause sustained generation losses of up to 40% in typical UK installations if not properly addressed.
- Bird droppings or dirt alone can drop output by 40%.
- Partial shading can create temperature spikes from 25°C to 105°C, increasing panel failure risk.
- Hotspots reduce panel lifetime outputs by 15% or more.
For trusted installation, maintenance, and system designs, Atlantic Renewables experts implement all leading technologies and industry best practices.
Get in touch
If you're considering solar PV for a roof with shading, or want advice on improving your existing system, contact Atlantic Renewables — the North West's specialist for solar installation and maintenance. Our knowledgeable engineers are happy to assist with any shading, output, or panel performance concerns. Call 0161 207 4044 today and start maximising your solar power potential!
