How do bifacial solar panels perform on flat versus sloped surfaces?

Bifacial solar panels are designed to capture sunlight from both the front and back sides, offering increased energy output compared to traditional one-sided panels. Their performance can vary significantly depending on whether they are installed on flat or sloped surfaces.

Performance on Flat Surfaces

On flat surfaces, bifacial solar panels can still generate electricity effectively, but their ability to harness reflected light from the back might be limited if not positioned optimally. For instance, if installed on a flat roof without sufficient tilt, the panels may not capture much reflected sunlight from the ground or roof surface. However, this can be mitigated by the type of surface beneath the panels. For example, lighter-colored roofs or reflective surfaces can enhance the energy output of bifacial panels by reflecting more sunlight back to the rear side.

In the UK, flat rooftops are common in urban areas, and bifacial panels can be a good option here, especially if combined with reflective roofing materials. UK homeowners and small businesses can increase their energy output with bifacial technology on flat roofs by maximizing reflected light absorption.

Performance on Sloped Surfaces

On sloped surfaces, bifacial solar panels typically perform better because the tilt allows more reflected light to reach the back of the panels. The angle of the slope is crucial; a well-tilted installation can significantly increase the energy output from the rear side, especially in scenarios where surfaces with high reflectivity are present beneath the panels. However, if the slope is too steep, the backside might not capture as much light.

For UK roof installations, sloped surfaces are more common and can be ideal for bifacial panels if aligned to maximize sunlight exposure. The ability of these panels to produce more energy when both sides are exposed to sunlight makes them suitable for maximizing energy production in residential and commercial settings.

Practical Advice and Considerations

• Reflective Surfaces: Ensure that the surface beneath the panels (whether flat or sloped) is as reflective as possible to maximize the bifacial effect. In the UK, using light-colored gravel or reflective roofing materials can enhance this performance.

• Optimal Tilt: For sloped installations, adjust the tilt to ensure that both the front and back benefit from sunlight exposure. This might require consulting with a solar panel professional.

• Installation Costs: While bifacial panels offer more energy potential, their initial cost is typically higher than monofacial panels. This may impact the decision for small businesses or homeowners on a budget.

• Common Mistakes: Avoid mounting bifacial panels too flush to a surface without considering how this will affect the backside light capture. Make sure there is enough space for reflected sunlight to reach the rear side.

Real-World Applications in the UK

In recent years, there has been an increasing focus on renewable energy in the UK, with policies like the Smart Export Guarantee (SEG) supporting homeowners who generate their own electricity. Bifacial solar panels can be an attractive option for those looking to maximize their solar output, whether on existing flat or sloped roofs. Their potential to produce up to 20% more energy than traditional panels makes them a valuable choice for UK homeowners and small businesses aiming to reduce their carbon footprint while benefiting from increased energy production.

Overall, bifacial solar panels can be an effective choice for both flat and sloped surfaces, provided they are installed with attention to the underlying surface reflectivity and panel tilt.