Do solar panels really need direct sunlight?

The truth about solar panels without direct sunlight

Contrary to popular belief, photovoltaic panels do not need direct sunlight to work. This is a question we are constantly asked by our Belgian customers, who are particularly concerned about the often cloudy climate in our region. The reality is far more encouraging than you might think!

Modern photovoltaic cells harness not only direct sunlight, but also what is known as diffuse light – the light that passes through clouds and scatters in the atmosphere. By 2024, this technology had advanced further, enabling installations to maintain significant output even on overcast days.

How solar panels work on cloudy days

The principle of diffuse light

When sunlight encounters clouds, it does not disappear completely. A significant portion passes through the cloud cover in the form of diffuse radiation. Photovoltaic panels capture this scattered light and convert it into electricity, albeit with reduced efficiency compared to sunny conditions.

• Thin clouds: 10–20% reduction in efficiency
• Medium clouds: 40–60% reduction in efficiency
• Thick clouds: 70–90% reduction in output

Technologies that optimise light capture

N-Type TOPCon bifacial panels represent the cutting edge of technology today. These modules, such as the HT-SAAE Jupiter 450W available from Wattuneed, capture light on both sides, thereby maximising output even in low-light conditions.

"Our Jupiter 450W panels achieve 22.8% efficiency thanks to their N-Type TOPCon bifacial technology, offering up to 20% more output compared to traditional panels, even in cloudy weather." – Wattuneed Technical Team

Actual performance in Belgium: the figures that matter

The year 2024 proved particularly revealing for the Belgian photovoltaic sector. Despite sunshine hours falling to 1,370 compared to 1,610 in 2023, modern installations maintained satisfactory output thanks to technological advances.

Maximising output without direct sunlight: our expert advice

Choose the right technology

To optimise output in low light, opt for:

1. Bifacial panels: Such as the Leapton N-Type 500Wp TOPCon, which captures reflected light
2. N-Type technology: Better performance in low-light conditions
3. High-efficiency cells: Efficiency exceeding 22% even in cloudy conditions

The importance of orientation and tilt

A well-designed installation can partially compensate for a lack of direct sunlight. In Belgium, the optimal orientation remains south with a tilt of 35°, but south-east and south-west orientations still perform very well.

Solar panel profitability in Belgium despite the climate

Realistic profitability calculation

Even with limited sunshine, 1 kWp produces an average of 950–1,000 kWh/year in Belgium. At current electricity prices (around €0.35/kWh), a 5 kWp system can generate:

• Annual production: 4,500 kWh
• Annual savings: €1,575
• Payback period: 4–6 years depending on the configuration

Storage solutions to optimise self-consumption

To maximise profitability even on cloudy days, storage becomes essential. Pylontech US3000C batteries allow you to store energy generated during sunny periods for use when the sky is overcast.

Technologies of the future: what does 2025 hold in store?

Game-changing innovations

The photovoltaic sector is constantly evolving to improve performance in low-light conditions:

• Perovskite cells: Promising 30% efficiency by 2030
• Concentrating panels: Optimise the capture of diffuse light
• Artificial intelligence: Real-time prediction and optimisation

The evolution of hybrid inverters

New-generation hybrid inverters incorporate optimised MPPT algorithms that extract maximum energy even in difficult conditions, increasing overall efficiency by 5 to 15%.

FAQ: Your questions about solar panels without sunlight

1. Do solar panels really work at night?

No, photovoltaic panels do not generate electricity at night. They require light, even if it is diffuse. This is why battery storage is essential for 24-hour energy self-sufficiency.

2. What is the minimum output in very overcast conditions?

Even in very cloudy weather, modern panels maintain an output of 10 to 25% of their maximum capacity. A 5kWp system can still produce 1 to 3 kWh per day.

3. Do the panels need cleaning more often in cloudy weather?

On the contrary! Frequent rain naturally cleans the panels. An annual professional clean is generally sufficient in Belgium.

4. Are bifacial panels worth the extra cost?

Absolutely, especially in Belgium. When installed on flat roofs, they partially compensate for the lack of direct sunlight through their ability to capture reflected light, increasing output by 15 to 30%.

5. How can you forecast production in changeable weather?

Modern monitoring applications incorporate weather forecasts to estimate production. Our Wattuneed systems include real-time tracking of your performance.

Your solar project with Wattuneed

As you will have gathered, solar panels do not need direct sunlight to be cost-effective in Belgium. The key lies in choosing the right equipment and an optimised design.

At Wattuneed, we support you in this energy transition with:

• A comprehensive range of high-performance panels
• Smart storage solutions
• Expert customer service from Monday to Friday
• Detailed installation diagrams
• A personalised production simulator

Don’t wait for perfectly sunny days to invest in solar power. With today’s technology, your system will be productive and profitable, even under the Belgian sky!

Wattuneed – Your renewable energy partner
12 Rue Henripré
4821 Andrimont, Belgium
Telephone: +32 87 45 00 34
Email: info@wattuneed.com

Free delivery on orders over €3,000 • Customer service Monday to Friday, 8.30am to 5.00pm • 100% secure payment