In order to generate electricity, solar panels only need exposure to daylight. They do not require warm weather, they do not require a bright sunny day and can even work when it is overcast.
In order to save money on increasing electricity bills, homeowners are increasingly looking towards solar power as a potential alternative, especially following a summer of heatwaves and near-constant sunny weather.
However, the big question we are commonly asked is whether they work in winter and how much electricity they should expect to generate relative to summer.
The answer can depend on a range of factors, but whilst solar panels typically generate less energy, the difference is not always as pronounced as many expect.
How Do Solar Panels Work In Winter?
Solar panels work through the use of photovoltaic cells, which react to light by generating electricity. This works in any daylight and does not require harsh direct sunlight to generate electricity.
Much like how ultraviolet radiation can still affect you even on a winter’s day, sunlight of any kind hitting the solar panel will generate electricity, although to what extent depends on the weather.
How Much Electricity Do Solar Panels Generate In Winter?
There is typically a reduction in electricity generation in winter, which can reach as low as 15 per cent of the power generated in summer, although the average is closer to 30 per cent.
The biggest reason for this is a matter of time; there are half as many daylight hours on average in winter as there are in summer, and less daylight means less of an opportunity for your solar panels to generate electricity.
As well as this, whilst solar panels will generate energy on cloudy days, thick cloud cover can cause a diffusion of light which can reduce the amount of sunlight they receive.
Similarly, rain and especially snow blocking the panels themselves can affect generation, although this is typically factored into their design and placement to avoid long-term disruption.
Finally, the sun hangs lower in the sky in winter than it does in summer, which can have an effect on the shadows being cast over the panels.
However, one confounding factor is that hot days often make solar panels less efficient, meaning that a solar panel on a bright but cold day will generate more power than during a heatwave.
Ultimately, whilst energy generation is lower, it is still significant enough to reduce energy bills, and installing solar panels in autumn and winter allows you to take account of the worst-case scenario so you can benefit from the influx of power in the summer.
What Factors Affect Solar Energy Generation
Quantifying how much energy is generated in winter depends on a wide range of factors, and installers will take these into account when planning your installation and providing a quote:
- Location – South-facing panels capture light throughout most of the day, especially in winter. Similarly, London will see more sun than Edinburgh due to latitude.
- Angle – A 35-degree angle is ideal for capturing light, but this can be adjusted depending on local factors.
- Shade – Taller buildings and trees will cast longer shadows in winter, affecting solar generation.
- Type of Panel – Different solar panels require lower light levels to work efficiently, with monocrystalline panels better suited to winter use.
