Do Solar Panels Need Direct Sunlight?
This is part of our guide to how solar panels work.
Solar panels are often associated with sunny skies and direct sunlight, but here's the good news for Scots facing a cloudy day, or three: modern solar panels don't need direct sunlight to generate energy. While direct sunlight is ideal, they can still perform under overcast skies or in partial shade. Here, we'll explain how this works, what factors affect low-light efficiency, and what it means for your energy savings.
Can Solar Panels Work with Indirect Sunlight?
Yes, solar panels can generate electricity even without direct sunlight. Solar cells absorb light particles (photons) to create electricity, and direct and scattered sunlight carry these photons. Think of it this way – if it's bright enough outside to see your solar panel, it's bright enough for it to generate power.
That said, solar panels' efficiency is lower in indirect sunlight conditions. Performance may only be 10-60% of what's achievable in full direct sunlight, depending on weather conditions, shading and the panel's technology.
Solar Panels in Scotland
Scotland’s weather means direct sunlight can be hit or miss. However, even with our famously cloudy skies, solar panels remain an effective renewable energy option, thanks to advancements in photovoltaic technologies and expert system designs.
Factors Affecting Solar Panel Efficiency in Low Light
Several factors determine how well solar panels perform in conditions like cloudy skies, shade or low-angled sunlight. Here’s what you need to know:
Angle of incidence
When sunlight hits a solar panel at an oblique angle (especially early in the morning or late in the day), the amount of light absorbed is reduced. To counter this, panels should ideally be installed to capture maximum sunlight. South-facing installations with an optimal tilt angle work best in the Northern Hemisphere.
Spectral distribution
Solar panels work best with wavelengths of light from certain parts of the spectrum. On cloudy days, light scattering in the atmosphere can shift the spectral balance, slightly reducing efficiency. However, newer panels are designed to absorb a broader range of light wavelengths.
Temperature
Higher temperatures can decrease solar panels' efficiency. Interestingly, Scotland's cooler climate gives solar panels an advantage, keeping temperatures in the optimal range for maximum energy generation.
Panel technology
Not all solar panels perform equally in low-light conditions. Certain types, like thin-film and amorphous silicon panels, handle diffuse light better than older crystalline-based panels. Advancements in half-cut cell technology and microinverters can also reduce the impact of shading, ensuring individual panels maintain some level of output despite partial obstructions.
Shading
Partial shading can significantly reduce panel output, whether from a tree or a chimney stack. Modern systems using microinverters or power optimisers can help mitigate this, ensuring one shaded panel doesn't drag down the entire system's efficiency.
Benefits of Solar Panels Despite Scotland’s Weather
While you might assume solar panels are best suited to sunnier climates, they are a viable option even in places with frequent overcast skies. Here’s why:
Year-round performance: Solar panels absorb visible and scattered sunlight, ensuring they work across all seasons.
Energy savings: Even with reduced output on cloudy days, each kilowatt-hour of energy generated translates into lower reliance on the grid and reduced energy use.
Eco-friendly impact: By generating green energy, solar panels help reduce your home’s carbon footprint, contributing positively to the environment.
Suited to cooler climates: Scotland’s moderate temperatures minimise efficiency loss due to overheating.
Modern design: Advanced technology offset low-light challenges, ensuring solar panels are effective in a wide range of conditions.
Maximise Solar Performance in Low-Light Conditions
Even with Scotland's weather, these tips can optimise your solar panel system:
Invest in the right technology: Choose panels designed for high performance in low light. Technologies like thin-film panels, microinverters, or power optimisers provide better reliability in varying conditions.
Expert positioning: Work with professionals to install panels at the best angle and orientation for your location. South-facing installations are ideal, but east and west orientations can also work well with additional optimisation.
Consider partial shading solutions: Use systems with microinverters to offset reduced output from shading.
Regular maintenance: Keep panels clean and debris-free to ensure maximum performance.
Harness Energy Savings with Solar Panels
While Scotland may not top the sunshine charts, it’s bright enough to make solar panels a worthwhile investment. Whether you’re saving energy during a typical Glaswegian drizzle or taking advantage of a sunny Highland afternoon, solar panels enable you to lower your energy usage and make your home more energy-efficient.
Interested in making solar work for your home? Explore your funding options to experience the benefits of renewable energy today!
