Solar panels have become popular as a cost-effective and sustainable way to produce electricity. In 2023, three-quarters of global renewable capacity additions were attributed solely to solar photovoltaic technology (PV). This dominance is poised to continue, with solar PV and wind power projected to account for a record-breaking 96% increase in renewable capacity additions over the next five years.
By 2028, solar PV and wind power additions are expected to quadruple compared to 2022 levels, shattering records throughout the forecast period and reaching a staggering nearly 710 gigawatts (GW). These figures underscore solar energy’s unprecedented growth and unwavering momentum within the global energy landscape.
This anticipated surge is driven by two key factors: declining generation costs in most countries and continued policy support for renewable energy solutions.
However, misconceptions about their ability to harness energy on cloudy days exist. This article aims to clear the air and answer the question: Do solar panels need to be in direct sunlight to function?
How do solar panels work?
Solar panels comprise photovoltaic (PV) cells built from semiconductor materials like silicon. When sunlight strikes the solar panel, its energy is absorbed by these cells, creating electrical charges that move within the cells due to their internal electrical field.
This movement of electrical charges is what we call electricity, which can then be used to power your home. This process, called the photovoltaic effect, is the foundation of solar energy generation.
Optimal conditions for solar panel performance
Unsurprisingly, direct sunshine provides the perfect circumstances for solar panels to produce electricity efficiently. Direct sunlight delivers the highest concentration of photons, allowing more electrons to be freed and generating more electricity.
While sunlight is undeniably the ideal scenario for solar panels to achieve peak efficiency, several other factors contribute to their optimal performance:
- Temperature
Contrary to popular belief, cooler temperatures are actually preferable. A temperature of 25 °C or 77 °F is optimum for optimal performance. As temperatures rise, the efficiency of the panels gradually decreases.
This occurs because heat can disrupt the internal workings of the photovoltaic cells, hindering their ability to convert sunlight into electricity effectively. Thankfully, most modern panels are designed to withstand a wide range of temperatures and maintain reasonable efficiency even in warmer climates. - Minimal shadingEven partial shading on a solar panel can significantly impede its electricity production. The presence of a small shadow can cause noticeable drops in power output. Furthermore, shading can cause harmful hot spots within cells, potentially resulting in permanent damage.When designing a solar system, it’s crucial to consider potential sources of shade throughout the year, such as nearby buildings, trees, or seasonal shadows cast by your roof.
- Panel cleanliness
Over time, dust, dirt, and other debris can accumulate on the surface of the panels, acting like a barrier and reducing sunlight absorption. This can reduce its efficiency. Regular cleaning, mainly after periods of heavy snowfall, dust storms, or long periods of dry weather, helps maintain optimal performance by ensuring the panels receive the maximum sunlight.
Read: How to clean your solar panels?
Solar panels and challenging weather conditions
While direct sunlight is preferable, solar panels can still function under challenging weather conditions like clouds, snow, and rain. However, these elements can reduce energy production. Clouds act as partial barriers, diffusing sunlight and decreasing the number of photons reaching the panels.
Minor snow buildup usually does not impact solar panel efficiency because the sun’s UV rays can penetrate a thin layer of snow. Although solar panels are built to endure heavy snowfalls, excessive accumulation can result in reduced production levels.
On the other hand, solar panels can typically operate in the rain since they are designed to catch and convert light into electricity. They will continue to generate power even in rainy or overcast weather, albeit at a lower efficiency.
Read: Solar panels and snow
Do solar panels work with indirect sunlight?
The answer is yes.
Why?
This is because photons, the component of the sun’s energy that solar panels use to generate electricity, exist in direct and indirect sunlight. Even though indirect sunlight (available during dawn and dusk hours) contains fewer photons than direct sunlight, solar panels can still be used for electricity generation.
This diffused light can be caused by clouds, reflection off surrounding surfaces, or the sun’s position in the sky throughout the day. While the output will be lower than in direct sunlight, it still contributes to your solar energy production.
How much direct sunlight do solar panels need?
Ideally, solar panels require at least 4 hours of direct sunlight daily for optimal performance. However, they can produce significant electricity even with less direct sunlight, especially if supplemented with indirect sunlight.
Solar panels that don’t need direct sunlight
While no solar panel operates entirely without sunlight, specific types are better suited for capturing and utilising indirect sunlight:
- Monocrystalline solar panels: These are built of a single piece of silicon, making it easier for electricity to pass through. Their pyramid cell layout provides a bigger surface area, allowing monocrystalline PV panels to capture more energy from the sunlight.
- Thin-film solar panels: These are constructed from a thin semiconductor film that can be directly applied to various surfaces. These panels utilise a broader spectrum of sunlight, including indirect sunlight.Thin-film technology inherently exhibits higher sensitivity to lower light levels. This means they can generate a relatively higher percentage of their rated power output under indirect sunlight than other panels.The effectiveness varies depending on the type of PV material used in the cells, but generally, they tend to have efficiencies ranging from 7% to 18%..
Although their absolute efficiency might be lower, thin-film panels deliver a greater percentage of their rated power in indirect sunlight, making them better for areas experiencing frequent cloud cover or limited direct sunlight exposure.
- Amorphous silicon solar panels: Amorphous silicon panels, made using CVD, excel in capturing low light due to their broad light absorption. This makes them ideal for areas with frequent shade or cloud cover, where consistent, lower power output is acceptable.However, their efficiency degrades faster than other panels, requiring careful consideration for long-term investments. They are not ideal for high-power applications.
- Bifacial solar panels: These innovative panels capture sunlight from both sides, utilising reflected light from the ground or surrounding structures, making them suitable for areas with limited direct sunlight.
- Multi-junction solar cells: These specialised cells, often used in space applications, are designed to absorb a broader range of sunlight wavelengths, including those in diffused light. However, their high cost makes them less common in residential applications.
Best solar panels for indirect sunlight
While all solar panels can generate electricity under indirect sunlight, some perform slightly better than others. Here’s what to consider when choosing panels for a location that receives significant indirect sunlight:
- For moderate budgets and balanced performance: Thin-film or amorphous silicon panels are good choices.
- For tight spaces and flexibility: Thin-film panels excel.
- For maximising energy production in diffused light: Consider bifacial panels, but be aware of their higher cost.
Ultimately, choosing the “best” solar panel for indirect sunlight depends on various factors, including your budget, energy needs, and specific sunlight conditions.
Consulting with a qualified solar panel installation company can help you find the panel type best suits your unique situation.
Frequently Asked Questions (FAQs)
Do solar panels need sunlight or just daylight?
Sunlight is a crucial component of “daylight.” While panels can generate minimal electricity on an overcast day, direct and indirect sunlight is essential for significant energy production.
Do solar panels work in shaded areas?
While solar panels can still generate some electricity in shaded areas, their performance will be significantly reduced. Shade, even for short periods, can dramatically impact overall energy production.
Do solar panels need heat or light?
Solar panels primarily utilise light, specifically the photons in sunlight, to generate electricity. While heat can affect their efficiency slightly, it’s not the primary factor driving electricity production.
Can solar panels get too hot from the sun?
Excessive heat can indeed negatively impact solar panel efficiency. Most panels are designed to operate within a specific temperature range; exceeding these limits can lead to reduced power output.
How to optimise solar panel performance in indirect sunlight?
- Minimise shading: Prune trees, remove obstructions, and strategically position panels to maximise direct sunlight exposure throughout the day.
- Choose the right panel type: Consider the specific types mentioned earlier (monocrystalline, thin film, etc.) for better performance in low-light conditions.
- Regular maintenance: Clean your panels periodically, at least twice in a year, especially after heavy snowfall, dust storms, or long stretches of dry weather. Dirt, dust, and debris can accumulate on the surface, hindering sunlight absorption and reducing efficiency. Follow the manufacturer’s cleaning recommendations to ensure proper cleaning techniques and avoid damaging the panels.
- Monitor performance: Regularly check your system’s performance and consult a professional if you suspect any significant decrease in output
How to power a solar panel without sunlight?
Unfortunately, solar panels cannot be powered without sunlight. They are designed to convert photons into electricity; without this energy source, they cannot function. However, if the sunlight is bright enough, you can charge the solar panel using various artificial lights, such as incandescent fluorescent bulbs.
Can solar panels work with artificial light?
While artificial light sources emit photons, they do not provide the same intensity or spectrum of light as sunlight. Therefore, solar panels are not designed or efficient in utilising artificial light for electricity generation.
Conclusion
Solar panels perform best in direct sunlight and can still function and contribute to your energy needs, even in challenging weather conditions or with indirect sunlight.
Understanding the factors affecting their performance and choosing the right panel type for your specific situation can optimise your solar experience and help you harness the sun’s power, even when it’s not directly shining.
Remember, consulting with a solar professional can provide valuable insights and ensure you maximise the benefits of solar energy for your home or business.
