What angle is optimal for installing bifacial solar panels?

The optimal angle for installing bifacial solar panels in the UK generally falls between 20° and 50°, with many experts recommending angles close to the latitude of the location, often between 40° and 45° for maximum annual energy generation. For example, around 47°N latitude (typical for much of the UK), an optimal tilt angle is close to 45°, which captures sunlight efficiently throughout the year.

Why angle matters for bifacial panels

Bifacial solar panels capture sunlight on both their front and rear sides—direct sunlight on the front and reflected or diffuse light on the back. This means:

• The tilt angle affects how much direct sunlight the front side receives.
• The ground reflectivity or albedo below the panel influences how much light the back side receives.
• Proper tilt and orientation maximize total energy yield by balancing front and rear irradiation.

Recommended angle and orientation for the UK

• Tilt angle: 40° to 45° is optimal for UK locations, matching or slightly less than the latitude. This ensures panels face the sun more directly on average across the year, which is key for fixed installations.
• Orientation: South-facing is best to maximize direct sunlight exposure. However, due to their bifacial nature, panels can also be installed vertically facing east-west to capture morning and afternoon sun on both sides.
• Vertical installations (close to 90° tilt) may be suitable in some cases, especially if ground reflectivity is high, but they tend to deliver less annual energy than optimally tilted panels.

Practical advice for UK homeowners and small businesses

If your roof pitch is already between 40° and 50°, installing bifacial panels at this existing angle often works well. For flat roofs or ground mounts, install panels on adjustable racks set close to 45° facing south for maximum return. Ensure the ground below panels is reflective to enhance the rear side output—white gravel or reflective surfaces help. Avoid installing bifacial panels at very shallow angles (<20°), as this reduces front irradiance and overall efficiency. East-west vertical setups are beneficial in some commercial sites where roof shape or shading is an issue.

Real-world examples in the UK

Many UK solar installations in counties like Yorkshire and Lancashire, around 53°N latitude, achieve optimal yields with bifacial panels tilted around 45°. These installations observe peak production in spring and autumn. Recent UK government policies have supported bifacial solar as part of renewable energy incentives, encouraging installations that maximize energy yield per unit area.

Key pros and cons of bifacial panels and their tilt

Pros	Cons
Increased total energy output (up to 15-20% more than monofacial panels)	Slightly higher upfront cost
Better performance in diffuse and reflected light, common in UK climate	Requires reflective ground surface or mounting structure for rear gain
Flexible mounting options (tilted or vertical)	Optimal angle may depend on site specifics
Enhanced durability and lifespan	Installation complexity can be higher

Common mistakes to avoid

Installing bifacial panels flat or at very low angles reduces direct sunlight capture on the front side. Neglecting ground surface reflectivity beneath panels, which lowers rear-side energy gain. Facing panels away from south (e.g., north-facing), which drastically cuts solar exposure in the UK. Assuming bifacial panels produce significantly more energy without optimizing angle, orientation, and ground conditions.

In summary, for bifacial solar panels in the UK, aim for a tilt angle close to 40°–45° facing south for most efficient year-round performance. If roof or site constraints exist, vertical east-west orientation can also work but may yield less total annual energy. Enhancing ground reflectivity and controlling shading are equally important to maximize the benefits of bifacial technology.