How much electricity do solar panels produce in winter?

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What about electricity generation from solar panels in the winter months? Photovoltaic panels are most efficient when they are fully illuminated by sunlight at the right angle. The ambient temperature also has an effect on the performance of the panels. In our geographical zone, winters tend to be cloudy, or at higher altitudes with some snow cover. In the following article, we will try to answer some important questions, so what about winter generation and what we can do to produce electricity as efficiently as possible.

• How do solar panels work in winter?
• Disadvantages of winter weather for solar panels
• How much energy do solar panels produce in winter?
• Maximising the efficiency of solar panels in winter

How do solar panels work in winter?

Solar panels do not mind the cold, on the contrary, if the ideal inclination of the panels towards the sun is ideal, the electricity production would be most efficient, the panel would be able to cool well and the performance would reach maximum values. The efficiency of the panel increases by up to 0.5% per degree below 25 °C.

However, several factors affect the performance reduction, such as clouds, snow, fog (humidity), and especially, as we wrote above, the inclination of the panel to the sun.

Disadvantages of winter weather for solar panels

There are several factors that can affect the efficiency of solar panels in winter:

Kratší dny

Když slunce vychází později a zapadá dříve, je menší časový úsek ve kterém solární elektrárna může získat nějaký výkon. Tím se snižuje celkový výkon elektrárny.

The sun is lower above the horizon

The sun doesn't rise as high during the winter months, which means its light has to pass through more of the atmosphere before it reaches your solar panels. Solar panels are not ideally inclined to get low sun. This all reduces the amount of energy hitting the panels and therefore reduces the panels' performance.

Cloud cover

Cloudy skies are more common during winter and can last for several days. With high cloud cover, not as much light reaches the panels and reduces the performance of the whole system. But even in this case, the solar power plant generates electricity.  ‍

Snow cover

If snow falls on your panels, it can significantly reduce the performance of the panels.

How much energy do solar panels produce in winter?

In winter, the amount of energy produced by a solar panel can be reduced by up to 80%.

The figure above shows the average hourly electricity production in kWh per kilowatt-peak of installed panel capacity. The curve is shown in yellow in summer and blue in winter.

While a 400 watt solar panel could produce approximately 2.4 kWh of energy on the sunniest summer day, it could only produce 0.4 kWh on the darkest winter day. The main reason for this is the shorter ideal illumination time of the panel and the inclination to the sun.

You can estimate the daily energy output of a solar panel using this formula:

Daily power (watt-hours) = panel power (watts) × time the panel will deliver maximum power (hours)  

So in winter a 400 watt panel would give you approximately:

400 watts × 1 hour = 400 watt-hours (0.4 kWh)

These are of course only rough estimates. Weather conditions, the angle and direction of your panels and other factors will affect the actual result.

The good news is that even on the shortest and cloudiest of days, solar panels still produce electricity. And while one panel may produce as little as 400 watts per day, your home could have 12 solar panels. In that case, they will still produce around 4.8 kWh per day.

Maximising the efficiency of solar panels in winter

In winter, considerable resources are spent, especially on heating buildings. Therefore, you will want to make the most of your solar power plant. But how to achieve this?

Here are some tips to maximize the efficiency of your solar panels in winter:

Keep them clean

Snow and ice chunks can block sunlight, so keep the panels clean for maximum performance. Snow doesn't stay on the panels for long; if the panels are inclined enough, the snow will spontaneously slide off the PV system. By shading the panels, the panels get a little warmer and the snow will slide off spontaneously. If this is not the case, you can help it a little. This means mechanically removing the snow from the panels. If you have a vertical inclination of the panels, the snow hardly stays on them.

Adjust the inclination of the sun

The sun is lower in the sky in winter, so by adjusting the tilt of the panels you can capture more light. This means tilting the panels more towards the sun. For winter, you can place the panels, for example, on a facade, etc., and then they capture more radiation when the sun is low. An interesting option is to place the panels vertically, for example as a fence or screen. This will allow you to take advantage of more eastern and western sunlight and extend the illumination time of the panel.

Monitoring and maintenance

A regular performance check can reveal improper shading or snow covering some panels. Monitor the performance of individual strings for anomalies.

Remove obstacles

The panels must be shielded as little as possible by the surroundings, make sure there are no obstacles in the path of the sun (trees, poles, antennas, etc.)

Add a battery to your solar system

Another tip for getting the most out of a PV plant is to install batteries to make better use of the power and create a supply on sunny days. This can then be drawn on days when it is more cloudy and conditions are not ideal for generating electricity.

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So, yes, a solar power plant works in the winter even though it most likely won't cover your energy needs over the whole winter, but the correct placement of the panels and the overall performance of the solar power plant can make a big difference. A good solution is to connect a single stringer only for the winter months with enough winter sun exposure. These panels will not have snow clinging to them and will have an ideal slope to the low rising sun. It will also help considerably to add batteries to the solar system, or to properly oversize them. However, batteries tend to be the most expensive item in the entire solar power system, so if you're interested in the return on investment, calculate whether it's worth it.

Sources: Profilesolar, Snugg