Solar and the winter, that’s a pretty big part of the whole renewables debate. 

Now, we are not going to claim that the UK winter will have no effect on your solar panels – you are obviously going to be producing less power because the country will be getting less daylight. 

But that doesn’t mean you’ll have no yield, and it doesn’t mean you can’t save money … because you absolutely can. 

Winter generation with Solar Panels. 

Solar panels, or PV panels, generate electricity from photons, or light particles, that come from the sun. 

Those particles hit the silicon cells in the panels and make the molecules ‘jiggle’, which creates a potential difference inside the cell and that’s where we get the electricity. 

If the light from the sun was as strong in winter as the summer, the temperature would make no difference to the amount of electricity you got.

But, the world isn’t built like that, so winter sun is a lot weaker, and we see less of it. 

This means winter generation can be 25% to 50% down on those long summer days. 

The one advantage of cold weather is that the silicon in your cells is kept cool, which reduces its resistance and means electricity can flow easier – increasing yield. 

How to get the best out of your solar system in winter

Although the yield will be lower in winter, that doesn’t mean it will be zero.

So, looking after your system, and using it wisely, is still the best way to save money. 

Keep you panels snow free

Believe it or not, modern solar panels can still produce energy with up to 6 inches of snow on them. 

Obviously, you don’t want to test that theory, and you are unlikely to need to do so with the amount of snow that we get here in the UK. 

All solar panels generate heat as part of the process of converting light energy into electric energy – so that usually keeps them clear of ice and snow if the weather isn’t too extreme. 

If there is a build up of ice or snow on the panels that lasts a few days, you will need to have them cleaned if you want them to produce electricity. 

You don’t want to, and we would strongly advice you don’t, climb on the roof and start spraying anti-freeze around. 

Your local window cleaner will be happy top come round and use his long window brush to get the panels all spick and span. 
But 99% of the time, your panels will simply clean themselves as the temperature rises slightly. 

Anti-Reflective Coating

Good quality, modern solar panels will have an anti-reflective coating on them. 

This is predominantly to ensure as much of the daylight as possible can reach the silicon cells at any time of year. 
A happy side effect of coating panels with this is it makes dust, debris, water and ice slide right off – most of the time. 

Battery Storage and Backup:
We always recommend battery storage when installing a solar energy system as it’s simply the best way to save even more money on your bills. 

During the longer days of spring, summer and autumn, your panels will produce more electricity that you can use in your home. 

This is due to the high yield and the fact most of us spend a huge chunk of the day part of the house. 

So, the best thing to do with that excess energy is to store it in batteries so you can use it when the sun goes down. 
That’s not where the advantages of having batteries stops though, as energy companies are getting wise to the customer’s needs and their new tariffs reflect this. 

Energy suppliers love to sell you cheap electricity at nigt because tey have nowhere else for it to go. 

Fossil fuel or nuclear power plants can not simply ‘switch off’ when the demand drops – it is far to expensive to restart them. 

So, they carry on generating a smaller amount of electricity even when demand decreases. 

The energy companies need to get rid of this energy, so they’ll sell it to you during the off-peak hours – at a fraction of the peak hours cost. 

You can fill your batteries up over night for as little as 4p an hour and use that power during the long winter evenings. 

Regular Maintenance

Solar Panels do not generally need a great deal of maintenance, but you should keep your eye on them during the winter. 

High winds, hail and extreme snow could damage panels, although in the UK that is highly unlikely. 

Damage is much more likely to come from small, hungry animals nibbling the cables, connectors naturally corroding or a manufacturing fault. 

Situations like this are incredibly rare and can be easily remedied by your local installer.

So, how much power am I getting in winter?

Estimates on winter generation for Solar Energy Systems can range from between 10% and 40% of your summer yield. 

However, the difference between one domestic system and another can be enormous – direction of panels, angle of panels, type of panels, inverters, shading, animal interference – these are all going to affect yield one way on another. 
 So, our advice is to concentrate on optimising your own system rather than compare it anyone else’s. 

What is the optimal temperature for solar panels?

Any solar panels that is described as ‘Tier 1’ and has MCS accreditation will have been put through some pretty rigorous testing. 

From hurricane wind speeds to golf ball-sized hail and a hundred other ‘freak weather’ simulations. 

One of the tests is to see at what temperature a panel will be the most efficient – subjecting them to temperatures from minus 40°C to plus 85°C. 

Those sorts of temperatures won’t be seen in our green and pleasant land anytime soon – so we just need to know panels perform best at around 20°C. 
On average, the temperature in Britain ranges from 18 to 25 °C – so that’s perfect.