Do solar panels need to be in the direct sun to generate any electricity at all? Here we explore the details.
A lot of people considering solar panels have the obvious question - do solar panels need direct sunlight to generate electricity?
Solar panels or photovoltaic modules do indeed require the energy of the sun i.e. sunlight to generate electricity. That’s why we recommend you install them outside.
But how much do they need? And is solar still worth the investment in a cloudy country like the UK? After all, the direct sun sometimes feels as rare as a Leicester City Premiership title.
In this guide, we explore this question in detail and explain how it's essential to choose a solar array system designed for the UK.
Let's begin...
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Do Solar Panels Need Direct Sunlight?
No, solar panels do not need direct sunlight to work and they will generate electricity in cloudy conditions too. Good news, since we generally need to go abroad to get a tan.
Solar panels work on the principle of something called the "photoelectric" effect which means the solar panels need sunlight or more specifically photons to hit them in order to generate a current and in turn electricity.
This means that the more sunlight exposure there is, the greater the production of electricity since more photoelectrons will be excited and released from the bonds within the panels. And when photoelectrons get excited, you will, too, when you see your electricity bill.
So on more sunny days and during summer solar panels do generate more electricity on average.
Ultimately, if you can see light outside, either direct or indirect, the solar panels can generate electricity.
How To Optimise Your Solar Array
Although your solar panels can generate electricity in direct or indirect sunlight or in cloudy weather conditions, it is certainly important to be aware of the factors that can limit electricity generation.
There are several steps you can take to maximise the power generated by your solar panels, especially in a cloudy place like the UK.
Here are the most important:
Choose the Right Direction
First of all, make sure they face upward. The ideal direction to install solar panels is to have them facing south since the UK faces the Northern Hemisphere.
This is because facing the south means the solar array will be facing the fun for the longest possible time.
However, if your property's roof is not facing south, you can still reap the rewards of installing solar if your roof faces the second best option - West, followed by East. Facing them north is a worse decision than the final season of Game of Thrones.
If your roof is north-facing or shrouded by too much shade, it may limit the electricity your panels generate.
But don't worry, this is all considered during the design process, start yours here.
Opt for Bifacial Solar Panels
Solar panels that are bi-facial will increase the amount of electricity generated compared to single-sided designs since they can absorb more of the sunlight from the underside - increasing their max power output by 10%.
Even better is to opt for panels with a double-glazed design, which means they are not susceptible to delamination, which is a common issue in inferior panels that over time causes the solar panel components to start detaching from each other. If that sounds bad to you, you’re correct.
Related solar guides:
Opt for Microinverters
The inverter is separate from your actual panels but plays a crucial part in any domestic solar installation.
The inverter's main role is to convert the energy generated by your solar panels from direct current (DC) to alternating current (AC) as this is the type of electricity domestic appliances and the National Grid use. Without an inverter, feeding solar energy to your appliances would be like using a wine bottle to feed your infant.
The most common and cheapest type of inverter for solar systems is string inverters (also called central inverters), however, they have a number of disadvantages and in a cloudy place like the UK, it's best to use a system designed with a microinverter (like we do, here at Heatable).
One of the major reasons for this is that it means the panels will start generating electricity in low light (requiring just 22 volts) – compare this to typical panels that utilise a string inverter that requires at least 200 volts to even begin energy generation - again, this makes them perfect for a cloudy place like the UK.
The microinverter design also means that each panel is able to work at its full capacity and maximise the performance of each solar panel independently.
Contrast this to a solar panel system that uses a traditional string inverter - if one panel's performance is impacted by shade or dirt, multiple other panels' performance will also drop, which is a significant disadvantage. It’s like running from a bear but having to keep the pace of the slowest person.
As mentioned, the micro-inverter (AC)-optimised design makes this solar system safer too - each panel is earthed and can be protected by an RCD board (fuse box), so is much safer than traditional DC systems.
Its AC-optimised design also means it will continue to work in the event of a power cut. This is not the case with DC systems - their inverters and batteries require grid power to operate.
Still learning about solar panels? Explore our helpful guides on various topics, including solar panel grants, payback periods, the mechanics of solar energy, determining the number of panels you need, and solar car charging solutions.
Cloud & Shade
Although solar panels can typically generate electricity with any amount of sunlight, it's worth noting that clouds and shading can reduce the amount generated.
This is especially true in systems that use a string inverter as DC systems, like those that use a string inverter rather than microinverters (AC systems). With a microinverter, pulling solar power from a cloudy sky is like driving with the handbrake on.
That's why it's so advantageous to opt for an AC system design, as in the UK it can mean a significant difference in your final payback period.
Opt for Solar Battery Storage
If you want to consume even more of the energy generated by your, store excess energy for use in the evenings and ultimately reduce your reliance on the National Grid consider battery storage.
No need for drumming bunnies for these batteries, because solar batteries are a whole different type.
The peak electricity generation with solar will coincide with the peak sunlight hours e.g. typically between 11 am and 2 pm in the UK.
However, the major problem is that most households are not at home during these times meaning that they are unable to utilise much of the energy (unless they have a solar battery that is).
For reference, the average 3-bed home with a solar system that consists of 10 panels will generate around 7.9kWh of electricity daily.
Yet, according to the Home Office, as of 2023, only around 19% of people work from home 5 days a week.
So, if these households each use a computer for around 7 hours and their dishwasher, they would consume around 7kWh of electricity, that's 88% of the total energy generated via solar.
However, if you are like the other 81% of the population and do not work from home, it means you won't be home to consume most of that free solar energy you've generated. Instead, you will be forced to draw more expensive electricity from the National Grid. So much for that expensive solar array.
Equally, although your household may not be using the energy as it’s being generated, if you’re selling your energy back to the grid through the day for a standard rate of 5p per kWh, you’ll then be buying electricity back from your provider at a standard rate of 36p per kWh later in the evening when you pop in that round of washing, turn the oven on for your casserole, watch the Corrie omnibus while you wait with lamps on in every room for “mood lighting”.
Explore a Solar Case Study: Check out an insightful Q&A session featured in one of our detailed case studies on domestic solar panels. Hear directly from a Heatable customer in the UK and gain valuable perspectives on their experience here.
The image above shows a 23-panel solar installation, carried out by the MCS-certified solar team at Heatable, featuring the REA Fusion2 solar panels.
Next Steps For Your Solar Journey:
When planning to install solar panels for your home, there are several important factors to consider. Make sure to refer to the following guides to help you make informed decisions:
To dive deeper into these topics, head over to our advice section, check out our YouTube channel for informative videos, or read a customer case study to see how others have benefited from their solar installation.
Get a Quote for Solar Today
Without boasting you should get your solar installed with us, here's why:
Thousands of Happy Customers: We boast an average score of 4.9 on Trustpilot, outperforming the market leader.
Which? Trusted Trader: Heatable is proudly recognised as a Which? Trusted Trader.
MCS Accredited: Our accreditation by the Microgeneration Certification Scheme (MCS) ensures high-quality standards.
Exclusive Panels: We offer REA Fusion solar panels, available only through Heatable.
Consumer Protection: As members of the HIES consumer code, we provide 2-year deposit protection.
Flexible Payment Options: Choose from multiple payment methods, including finance options.
Fixed Price Guarantee: Enjoy transparency with no hidden costs.
Save Your Quote: You can save your quote and decide later.
Bespoke Design Tool: Draw your own conclusion (literally) on whether solar is worth it for you, here.
