Vertical Bifacial Solar Outperforms Tilted Panels in the UK: What a Year-Long Study Found
A year-long empirical study at the University of York has found that vertical bifacial solar panels can outperform conventional tilted rooftop solar across every season of the British climate, according to reporting from pv magazine on research published in the journal Scientific Reports. For anyone deciding whether vertical solar makes sense outside of sunny, low-latitude climates, this is one of the more detailed independent data sets available.
8/18/20262 min read
What was tested
Researchers monitored a vertical bifacial photovoltaic system installed on the rooftop of the university's physics tower over a full annual cycle in 2023. The system, supplied by Norwegian vertical solar specialist Over Easy Solar, used high-efficiency heterojunction cells and was installed above white gravel chosen to bounce additional light onto the rear side of the bifacial panels. Its performance was compared against both a vertically mounted monofacial system and a conventional tilted monofacial system installed at the standard 45-degree angle common in UK solar installations.
Morning and evening performance gains
According to pv magazine's reporting, the vertical bifacial system produced up to 26.91% more output than the tilted system during early morning hours, and 22.8% more during early evening hours. This "double peak" pattern is a defining characteristic of vertical bifacial technology: rather than concentrating generation around midday, as tilted panels do, a vertical array captures more usable light when the sun sits low on the horizon, which happens to align closely with typical household demand spikes for heating, cooking and EV charging.
Seasonal results, including winter
The vertical bifacial system beat the tilted comparison system across all four seasons, with the gap widest in winter. Reported seasonal gains ranged from roughly 14.8% in summer up to about 24.5% in winter, reflecting the system's ability to make effective use of low-angle winter sun and diffuse light, conditions where conventional tilted panels are typically at their weakest.
Cost and payback considerations
The pv magazine article also cites cost figures from Over Easy Solar suggesting that a vertical bifacial system carries a higher upfront cost per kilowatt than a traditional tilted system, but that the additional energy yield, particularly during higher-priced demand periods, can translate into a faster payback period despite the higher initial investment. Wind testing referenced in the reporting also found the system maintained low lift forces even at wind speeds close to 100 km/h, a relevant data point for coastal and exposed sites.
Why this matters beyond the UK
The UK and Irish climates share meaningful similarities with much of Northern and Central Europe, including Switzerland: relatively low sun angles for large parts of the year, significant diffuse and overcast light conditions, and residential demand patterns that peak outside the midday hours when conventional solar performs best. Independent, peer-reviewed performance data from a climate like this is directly relevant to evaluating whether vertical solar can perform well beyond the sunnier climates it is sometimes associated with.
Key takeaways
Outperforms tilted panels in every season: including a striking advantage in winter months.
Double peak generation: higher output during morning and evening hours aligns with residential demand patterns.
Wind resilience: testing referenced in the reporting found low lift forces at high wind speeds.
Higher upfront cost, faster payback: increased yield can offset a higher initial cost per kilowatt.
Relevant beyond the UK: findings are applicable to other temperate, diffuse-light climates.
FAQ
Does vertical bifacial solar really work better than tilted panels in cloudy climates?
According to this year-long UK study reported by pv magazine, yes: the vertical bifacial system outperformed the tilted comparison system across all four seasons, including winter.
Why does vertical orientation help with morning and evening output?
Vertical panels are positioned to capture low-angle sunlight more effectively than tilted panels, which are optimized for direct overhead midday sun.
Is vertical bifacial solar more expensive to install?
The reporting cites a higher initial cost per kilowatt for vertical bifacial systems compared with traditional tilted systems, though higher energy yield can shorten the payback period.
Explore vertical solar for a similar climate
Lumiton Solar can help assess whether the seasonal performance advantages demonstrated in this UK study apply to your site's climate and energy needs.