Do solar panels work in winter and how effective are they?

Solar panels with cloudy weather

RACV

Posted April 02, 2024


One in four Australian houses now experience the benefits of renewable solar power to run everything from heating and cooling to electric vehicles. But how effective are solar panels in winter?

As the demand for renewable energy continues to rise, many households are curious about the efficacy of solar panels during winter  and on cloudy days. Contrary to a common misconception, solar panels are indeed capable of producing energy during colder weather as they rely on light, and not heat, to operate all year round. 

Find out how solar energy works during winter to help make an informed decision about renewable energy in your home. 

 

Solar panels can make your home more energy efficient | RACV

Do solar panels work in winter? 

How efficient are solar panels in winter? 

RACV Solar spokesperson Himanshu Ahuja says the efficacy of solar panels during winter depends on several factors, including the angle of the panels, daylight duration, and weather conditions. 

"Panels are still efficient in winter and can still generate energy during the winter months, although their efficiency may be slightly reduced due to shorter days, lower sunlight angles, and potential snow cover,” Ahuja says. 

The sun sits lower in the sky during winter, affecting the way it hits the solar panels. While the overall efficiency may decrease slightly, modern solar technologies are designed to capture and convert sunlight into energy, even under less-than-ideal conditions.

“Overall, while the effectiveness of solar panels may decrease slightly in winter, they can still contribute to energy generation for your household,” Ahuja says.

At what temperature do solar panels stop working?

Solar panels are designed to withstand a range of temperatures, so shouldn’t abruptly stop working.  

“Cold weather generally doesn't impact solar panels,” says Ahuja.

“Extreme cold temperatures can affect the panel efficiency, but they typically do not stop working altogether.”

In fact, extreme heat can sometimes reduce their effectiveness more than cold temperatures. 

Most solar panels operate effectively in a temperature range between minus 30°C and up to 80°C, says Ahuja, meaning the mild winter temperatures experienced in Australia are unlikely to impact.

How much power will my solar panels generate in winter? 

Ahuja estimates that solar panels can still produce, on average, 50 to 80 per cent of their maximum output during the winter months.

“The amount of power generated by solar panels in winter can vary depending on several factors, including the specific location, weather conditions, orientation of panels, and any shading or obstructions,” he says.

While it's true that there might be a decrease in sunlight hours during winter, advancements in solar technology have mitigated this impact. 

“In general, solar panels can still generate a significant amount of power during winter months, although their output may be lower compared to summer months,” he says.

 

Solar panels on roof

Solar panels can generate energy on cloudy days and during shorter daylight hours. Image: Matt Harvey.


 

Should I turn off solar panels in winter? 

There is typically no need to turn off the solar panels during winter, says Ahuja. Solar panels can still generate energy even on cloudy days or during shorter daylight hours. 

Homeowners are better off keeping their solar panels operational throughout the year to benefit from the energy they can produce, even during the winter months.

Does a home solar battery work in winter?

A solar battery may be effective in helping to reduce your energy costs in winter if your solar panels are generating excess energy. 

When your solar panels generate more energy than you can use, the unused energy is exported to the grid. Depending on your arrangement with your energy provider, you can receive a feed-in tariff or credit on your bills, which is paid in cents per kilowatt-hour.  

However, this feed-in tariff is much lower than what you would pay an energy retailer for electricity imported from the grid, says Ahuja.

“Excess energy generated from solar panels flows back to the grid for a set feed-in tariff, which is generally a lot lower than what you are charged by the retailer,” he says.  

“Having a solar battery means excess unused energy is stored, and can be used for  household consumption when the sun is not shining, such as night-time. This benefits the household by not having the need to buy power from the grid at a higher rate.”  

Ahuja recommends batteries from a certified solar provider so you can generate, store and manage your own energy.

“Batteries also provide back-up power during grid outages, supplying energy to essential appliances or the entire home, depending on capacity and configuration.”

Batteries with a back-up function also allow the power to run during a winter blackout.

More: Guide to Tesla home solar batteries

How many kWh of electricity should my solar panels generate in winter?  

Professionally installed solar panels that are well maintained can still generate a substantial amount of energy during winter in Australia, and contribute significantly to reducing energy bills.

The ideal kWh (kilowatt-hour) production for a solar panel system in winter varies depending on the size and capacity of the installation. 

“The amount of kWh depends on various factors such as system size, efficiency, location, shading and weather conditions,” Ahuja says.  

“For example, you can expect a 5kW system to produce around 10-15kWh in winter, and around 20-25kWh in summer.”

Why have my energy bills increased in winter even with solar panels? 

If your energy bills have increased during winter despite the presence of solar panels, it could be due to various reasons. 

One common factor is increased energy usage. “During winter, households often use more energy for heating,” Ahuja explains. “This additional usage can offset the electricity generated by solar panels, leading to higher overall energy bills.” 

Additionally, shorter daylight hours and potential shading issues could impact solar panel efficiency.  

“Due to shorter days and the lower angle of the sun, your panels might reduce their efficiency, resulting in lower power generation.”

Regular maintenance, checking for shading, and optimising the solar panel system can help address these concerns and ensure best performance.

 


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