How Much Energy Does a Solar Panel Produce?

If you’re a UK homeowner considering solar energy, one of the first questions you might ask is, “how much energy does a solar panel produce?” Understanding the energy output of solar panels will help you determine whether they can meet your home’s energy needs, save you money and contribute to a greener future. 

The energy a solar panel produces depends on multiple factors, ranging from the panel type to roof orientation and even the UK’s famously unpredictable weather. This guide breaks it all down for you, including step-by-step instructions on calculating your energy needs and leveraging our interactive quote tool to plan your solar investment. 

How Much Energy Does a Solar Panel Produce in the UK?

The energy production of a solar panel depends on its size, efficiency, and the amount of sunlight it receives. Most residential solar panels in the UK produce between 250 and 400 watts per hour during peak sunlight translating to roughly 1 to 1.5 kilowatt-hours (kWh) per day per panel. 

For a standard 4 kW solar panel system (around 10-12 panels), you could generate between 3,000 and 4,200 kWh of electricity annually. To put this into perspective, the average UK household uses about 2,900 kWh of electricity per year, meaning a typical solar array can meet—and often exceed—a household’s annual electricity needs. 

That said, the energy output is influenced by several factors, which we’ll explore next.

How Much Energy Does a Solar Panel Produce: Key Factors

Type of Solar Panel: Not all solar panels are created equal. Here’s an overview of the three main panel types commonly used in the UK and their energy performance: 

Monocrystalline Panels 

  • Efficiency: 15-22% 
  • Key Features: These panels are built from a single silicon crystal, making them highly efficient and space-saving. 
  • Performance in the UK: Excellent for maximising energy production even on cloudy days and perfect for homeowners with limited roof space. 

Polycrystalline Panels 

  • Efficiency: 13-16% 
  • Key Features: Made from multiple silicon fragments and more affordable but slightly less efficient than monocrystalline panels. 
  • Performance in the UK: Cost-effective for sunny areas, but slightly less effective on overcast days compared to monocrystalline panels. 

Bifacial Panels 

  • Efficiency: 15-20% 
  • Key Features: These panels harness sunlight from both sides, increasing their energy production in areas with reflective surfaces (e.g., light-coloured roofing or nearby concrete).
  • Performance in the UK: Ideal in specific installations but dependent on proper mounting and environment. 

How Much Energy Does a Solar Panel Produce: Roof Characteristics 

Your roof plays a crucial role in determining how much energy your solar panels can generate. Consider these key factors: 

Orientation and Tilt 

  • South-facing roofs are optimal, as they capture the most sunlight throughout the day. 
  • East- or west-facing roofs produce around 15-20% less energy. 
  • A roof tilt of 30-40 degrees is ideal for solar panels in the UK. 

Shading 

Areas of your roof shaded by trees, chimneys, neighbouring buildings, or other obstructions can significantly reduce energy production. During installation planning, solar professionals will conduct a shading analysis to determine the optimal layout for your system. 

Roof Size and Available Space 

Larger roofs can accommodate more panels, increasing potential energy production. However, even small roofs can yield significant energy output when fitted with high-efficiency panels. 

Environmental Factors 

UK Climate 

The sunny days of Southern England might seem more favorable for solar than the overcast skies of Northern Scotland, but modern solar panels are designed to perform well even in cloudy conditions. Additionally they can generate electricity from diffused sunlight. 

Seasonal Variation 

Solar panels produce the most electricity during summer when days are long and sunny. Conversely, Winter months will see lower energy output, but your system’s battery storage (if installed) can help balance these fluctuations. 

Temperature 

Interestingly, extreme heat can reduce solar panel efficiency. However, the UK’s mild climate ensures that solar systems typically operate at optimal performance.

How to Calculate Your Solar Energy Needs 

Now that you understand how solar energy production works, it’s time to calculate how much energy you need—and how many panels can meet your requirements. Follow this step-by-step guide, which integrates our interactive quote tool for an accurate calculation. 

Step 1: Assess Your Current Energy Usage 

  • Firstly review your energy bills to determine your annual kWh usage. Example: The average UK household consumes around 2,900 kWh annually although this varies based on home size and appliance use. 

Step 2: Evaluate Your Roof 

  • Secondly enter your postcode into our interactive quote tool to analyse your roof’s suitability for solar panels using satellite images. Our quote tool allows you to evaluate roof orientation, tilt, shading and panel layout. You’ll get recommendations on panel types, system size, and optional battery solutions to suit your home. Finally a full assessment of your roof will also be undertaken by our Solar Experts prior to installation.
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How Much Energy Does a Solar Panel Produce: Battery Storage Options

Adding a battery storage system allows you to store excess energy for later use, which is particularly useful during evenings or winter months. For this reason you should consider battery storage if you aim to maximise solar energy self-sufficiency. 

Why Choose Solar Panels for Your UK Home? 

Making the switch to solar energy offers numerous benefits for UK homeowners, including:

  • Reduced energy bills through self-generated electricity. 
  • Power Outage Protection
  • Contributions to sustainability with lower carbon emissions. 
  • Earnings from surplus energy sold back to the grid via the Smart Export Guarantee (SEG). 

Even with the UK’s variable weather, solar panels are an excellent long-term investment for energy independence. 

How Can E-Verve Energy Help?

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The question of “how much energy does a solar panel produce?” is just the beginning of your solar energy journey. Now that you understand the key factors and how to calculate your energy needs, take the next step by using our interactive quote tool. Get your solar cost upfront with no pressure to commit and see how much solar panels could save on your bills! We’re here to help you find the perfect setup for your home.

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Installing solar panels is a fantastic step toward energy independence and a smaller carbon footprint. You get to power your home with clean, renewable energy straight from the sun. But what happens on those bright, sunny days when your panels generate more electricity than your home is using? This surplus energy doesn’t have to go to waste. You have several smart options to make the most of every kilowatt.

How Much Energy Does a Solar Panel Produce?

Before we dive into managing surplus energy, it’s helpful to understand what your system can generate. The output of a solar panel system depends on several factors, not just the number of panels you have. These include the panel’s power rating (measured in watts), its efficiency, and the amount of direct sunlight it receives.

Key factors influencing production include:

  • Geographic Location: A home in a sunnier climate will get more direct sunlight than one in the UK.
  • Time of Year: You’ll generate more power during the long, sunny days of summer than in the shorter, often cloudier days of winter.
  • Panel Orientation and Tilt: Panels facing south (in the Northern Hemisphere) with an optimal tilt angle capture the most sunlight throughout the day.
  • Shading: Trees, nearby buildings, or even chimneys can cast shadows on your panels, reducing their output.

Option 1: Store Excess Energy in a Solar Battery

One of the most popular and effective ways to handle surplus solar power is to store it in a battery. A solar battery storage system acts like a rechargeable power bank for your home. During the day, when your panels are at peak production, any electricity you don’t use immediately is sent to charge the battery.

Then, in the evening or on cloudy days when your panels aren’t producing, your home can draw power from the battery instead of pulling it from the utility grid. This dramatically increases your energy self-sufficiency and reduces your reliance on your electricity provider.

The Benefits of Battery Storage
  • Energy Independence: Use your own solar energy 24/7, even when the sun isn’t shining. This gives you more control over your power supply.
  • Lower Electricity Bills: By using your stored energy instead of buying from the grid during peak evening hours, you can significantly cut your monthly utility costs.
  • Backup Power: Many solar battery systems can provide backup power during a grid outage. This keeps your essential appliances—like lights, refrigerators, and medical devices—running smoothly.
  • Environmental Impact: Storing and using your own clean energy ensures that none of it is wasted, further reducing your household’s carbon footprint.

While the initial investment for a battery system can be significant, prices are falling, and the long-term savings and energy security often make it a worthwhile addition to a solar panel installation.

Option 2: Sell Your Energy Back to the Grid

If you don’t have a battery, your system usually sends any excess solar energy back to the public electricity grid. The good news: you can often get paid for this surplus energy. In many regions, utility companies must compensate homeowners for the clean energy they supply. Programs like the Smart Export Guarantee (SEG) manage these payments.

Understanding the Smart Export Guarantee (SEG)

Under the UK government-backed Smart Export Guarantee (SEG), large licensed electricity suppliers must pay small-scale generators for the low-carbon electricity they export to the grid. If you have a solar panel system, you can sign up for an SEG tariff with a participating supplier.

Here’s how it works:

  • Choose a Supplier: You don’t have to get your SEG tariff from the same company that supplies your electricity. It pays to shop around, as rates can vary significantly between providers.
  • Get Paid for What You Export: Under the SEG, you earn payment for every unit of electricity (kWh) you send back to the grid. Your smart meter precisely measures your export, and you receive fair compensation.
  • Variable Rates: SEG tariffs can be fixed or variable. A fixed rate pays you a set price per kWh, while a variable rate might change based on the time of day or wholesale energy prices. Some innovative tariffs offer higher payments for exporting during peak demand periods.

Selling your excess power provides a direct financial return on your solar investment. It helps shorten the payback period for your system and provides a small but steady income stream.

Other Ways to Use Surplus Solar Power

Beyond battery storage and grid export, there are other creative ways to ensure your surplus energy is put to good use.

Divert Power to a Hot Water Heater

A solar power diverter is a clever device that monitors your energy production and consumption. When it detects surplus electricity being generated, instead of sending it to the grid, it redirects the power to an immersion heater in your hot water tank.

This essentially uses your excess solar energy to give you free hot water. It’s an excellent way to reduce your gas or electricity bills associated with water heating, which is one of the largest energy expenses in many households.

Charge Your Electric Vehicle (EV)

If you own an electric vehicle, your surplus solar power offers a perfect synergy. Many modern EV chargers, known as smart chargers, can be programmed to use only the excess solar energy generated by your panels.

This means you can charge your car for free during the day. By timing your charging sessions to coincide with peak solar production, you can fuel your vehicle with 100% clean, self-generated energy, dramatically reducing your transportation costs.

Conclusion: Making the Most of Your Solar Investment

Knowing how much energy a solar panel produce is just the first step. The real value comes from effectively managing that production. When your system generates more power than you need, you have powerful options at your disposal.

  • Battery storage offers energy independence and security, letting you use your own solar power around the clock.
  • Selling back to the grid through programs like the SEG provides a direct financial return, helping to pay off your system faster.
  • Diverting to heat water or charge an EV allows you to offset other major household expenses with free, clean energy.

Many homeowners invest in solar panels to gain energy independence and reduce their reliance on the grid. It’s a common assumption that if the grid goes down, your solar panels will keep your lights on. However, the answer is more complex than a simple yes or no. For most standard, grid-tied solar systems, the answer is surprisingly, no—they will not provide power during an outage.

This is a built-in safety feature to protect utility workers who are trying to repair the power lines. If your system continued to send electricity to the grid, it could create a dangerous situation for them. But don’t worry, there are specific steps you can take to ensure your solar panels become a reliable source of backup power when you need it most.

Why Standard Solar Systems Shut Down

Most residential solar panel systems are “grid-tied.” This means they are connected to the main electrical grid. Your system generates power, which is first used by your home. Any excess energy is then sent back to the grid. This relationship works both ways; when your panels aren’t producing enough power, like at night, you draw electricity from the grid.

To manage this two-way flow, systems use an inverter. The inverter’s job is to convert the direct current (DC) electricity produced by your solar panels into alternating current (AC) electricity that your home appliances can use. Grid-tied inverters sense the grid’s electrical frequency. When they detect a power outage and the grid becomes inactive, they automatically shut down. This safety protocol, known as “anti-islanding,” prevents your system from energizing the grid and potentially harming utility line workers.

So, while your panels may be soaking up the sun, a standard grid-tied system without any additional hardware will not power your home during an outage.

How to Get Backup Power from Your Solar Panels

To keep your home powered during a blackout, you need to add components that allow your system to safely disconnect from the grid and operate independently. This is typically achieved by installing a solar battery storage system.

Step 1: Install a Solar Battery

A solar battery is the key to unlocking backup power capabilities. It acts as an energy reservoir for your home. During the day, when your panels are producing more electricity than you need, the excess energy is used to charge the battery instead of being sent to the grid.

When a power outage occurs, a special device called an automatic transfer switch (ATS) immediately and safely disconnects your home from the grid. Your system then begins to draw power from the charged battery, keeping your essential appliances running. If the outage happens during the day, your solar panels can continue to generate power to run your home and even recharge the battery simultaneously.

Benefits of adding a battery include:

  • Uninterrupted Power: Enjoy seamless power for critical loads like refrigerators, lights, and medical devices.
  • 24/7 Solar Energy: Use your stored solar energy at night or on cloudy days, further reducing your reliance on grid electricity.
  • Increased Self-Sufficiency: Gain true energy independence by generating, storing, and using your own clean power.
Step 2: Ensure Inverter Compatibility

Not all inverters are created equal. To enable backup power, you need an inverter that is compatible with a battery system. These are often called “hybrid inverters” or “storage-ready inverters.”

  • Hybrid Inverters: These multi-functional inverters can manage the power flow from your solar panels, your battery system, and the grid all in one unit. They are an all-in-one solution for new solar-plus-storage installations.
  • AC-Coupled Systems: If you already have a standard grid-tied solar system, you can still add a battery. This is done through “AC coupling,” where a separate battery-specific inverter is installed alongside your existing solar inverter. The battery inverter manages the charging and discharging of the battery.

When planning your system, it is crucial to discuss backup power as a goal with your installer to ensure they select the right type of inverter for your needs.

Step 3: Understand Your Power Needs

A common question is, how much energy does a solar panel produce, and will it be enough during an outage? The answer depends on your system size, battery capacity, and what you want to power. A typical solar panel produces between 1.5 and 2.5 kWh per day, but this varies based on sunlight, location, and weather.

Before an outage, you should identify your “critical loads”—the essential appliances you cannot live without. This might include:

  • Refrigerator and freezer
  • Lights in key areas
  • Well pump (for homes with well water)
  • Medical equipment
  • Internet router and phone chargers

Your solar installer can help you calculate the energy consumption of these critical loads to determine the appropriate battery size. A larger battery will provide power for a longer duration or support more appliances, but it also comes at a higher cost. It’s about finding the right balance between security and budget. Some systems are designed to power the entire home, while others are set up to only support a sub-panel of essential circuits.

Conclusion: Prepare for Peace of Mind

While a standard solar panel system won’t automatically protect you from a power outage, it is entirely possible to build a system that will. By incorporating a solar battery and a compatible inverter, you can transform your solar installation into a reliable source of backup power. This setup allows you to safely disconnect from the grid and use your own stored, self-generated electricity to keep your essential appliances running.

Taking these steps provides more than just convenience; it offers energy security and peace of mind. Knowing that you can weather a blackout with your own clean power is one of the most significant benefits of a well-designed solar-plus-storage system. You maximise your investment, increase your home’s resilience, and achieve true energy independence.

You’ve crunched the numbers, looked at your electricity bills, and decided that solar power is the way forward. But then comes the hurdle: your roof isn’t right for panels. Maybe it faces the wrong direction, a massive oak tree shades it, or the structure itself simply can’t support the weight.

Don’t let this setback dim your solar ambitions. A roof installation is the most common way to go solar, but it certainly isn’t the only way. In fact, for many homeowners, alternative installation methods can actually be more efficient than a traditional rooftop setup.

Why Might a Roof Be Unsuitable?

Before looking at alternatives, it’s worth briefly noting why a roof might be rejected for solar. This helps you understand what you are trying to overcome with an alternative method.

  • Orientation: In the Northern Hemisphere, south-facing roofs are ideal. East or west can work, but north-facing roofs often lose too much efficiency.
  • Shading: Chimneys, dormer windows, or neighbor’s trees can cast shadows that kill solar production.
  • Structural Integrity: Older roofs might not support the weight of the racking and panels without expensive reinforcement.
  • Space: Sometimes, the usable roof area is simply too small to host a system large enough to make a dent in your bills.
  • Aesthetics: You might live in a listed building or a conservation area where street-facing roof alterations are prohibited.

If you fall into any of these categories, wall-mounted or ground-mounted systems could be your solution.

Option 1: Wall-Mounted Solar Panels

If your roof is a no-go but you have a large, sunny wall, wall-mounted solar panels are an excellent alternative. As the name suggests, these panels are fixed vertically to the side of your building.

How Do Wall-Mounted Panels Work?

These systems use specialized mounting hardware to secure the panels flat against the facade or tilted slightly outwards. They function exactly like rooftop panels, converting sunlight into electricity that flows into your home’s main supply.

The Benefits of Vertical Solar
  • Winter Efficiency: Interestingly, vertical panels can outperform roof panels during winter. The sun is lower in the sky during colder months, meaning it hits a vertical surface more directly than a horizontal one.
  • Self-Cleaning: Snow doesn’t accumulate on a vertical wall, and rain washes dust and pollen away much more effectively than on a shallow-pitched roof. This keeps maintenance low.
  • Cooling Effect: Solar panels mounted on a wall can actually shade the building itself, potentially reducing the cooling load in summer.

Important Considerations for Wall Mounting

The biggest question homeowners ask is: how much energy does a solar panel produce when mounted on a wall?

Generally, a vertical panel will produce slightly less total energy over a full year compared to an optimally tilted roof panel. This is because the summer sun is high in the sky, glancing off the vertical surface at a steep angle. However, if your wall faces south and remains unshaded, you might notice negligible differences, especially when you prioritize winter production during higher electricity rates

You also need to consider the weight. The wall must be structurally sound to hold the panels and withstand wind loads. A structural engineer’s assessment is usually required.

Option 2: Ground-Mounted Solar Panels

If you have garden space or land available, ground-mounted solar panels are often the superior choice. This involves installing a racking system directly into the ground, usually on concrete footings or driven piles, to hold the panels.

Why Ground Mounts Are Often Better Than Roofs

Ground-mounted systems free you from the constraints of your house’s architecture. You aren’t limited by the direction your roof faces or the angle of its pitch.

  • Perfect Orientation: You can point the panels exactly due south (or north, in the Southern Hemisphere) to capture the maximum amount of sunlight.
  • Optimal Tilt: You can set the panels at the perfect angle for your latitude. Some advanced systems even allow you to adjust the tilt seasonally—steeper in winter, flatter in summer—to squeeze every drop of energy from the sun.
  • Airflow and Cooling: Solar panels lose efficiency as they get hot. Roof panels often trap heat between the panel and the shingles. Ground-mounted panels have excellent airflow on all sides, keeping them cooler and operating more efficiently.
  • Easy Maintenance: No need to climb a ladder to clean your panels or clear off snow. Everything is accessible from the ground, making maintenance safer and easier.
Types of Ground Mounts
  1. Standard Ground Mounts: These use a metal framework to hold panels at a fixed angle. They are sturdy, reliable, and the most common type of ground installation.
  2. Pole Mounts: These involve a single, heavy-duty pole that holds a large array of panels higher off the ground. This leaves the ground below open for gardening or mowing. Some pole mounts incorporate “trackers” that physically move the panels to follow the sun across the sky, boosting production by up to 25%.

Space and Cost

Ground-mounted systems typically require more materials (concrete, steel tubing) and labor (trenching for wires) than roof mounts, making the upfront cost higher. They also take up yard space. However, because you can optimize their placement so perfectly, the increased energy production often offsets the higher installation cost over time.

How Much Energy Does a Solar Panel Produce in These Setups?

This is the critical metric. You need to know if the investment is worth it.

A standard residential solar panel is rated between 300 and 450 watts. Under ideal “test conditions,” a 400-watt panel produces 400 watt-hours of energy for every hour of full sun.

  • Ideally Oriented Ground Mount: This setup will likely hit closest to that maximum rating. Because you can control the tilt and direction perfectly, a 4kW ground-mounted system could produce 3,500 to 4,200 kWh per year in a sunny climate.
  • South-Facing Wall Mount: A vertical wall mount might produce roughly 70-80% of what an optimally tilted roof system would produce in summer, but potentially more in winter. Over a year, a 4kW wall system might generate around 2,800 to 3,200 kWh.

Ultimately, the answer to “how much energy does a solar panel produce” depends heavily on your specific location and installation method. But even at slightly lower efficiencies, these alternative systems can generate enough power to significantly lower your utility bills and carbon footprint.

Conclusion

A difficult roof doesn’t mean the end of your renewable energy journey. In fact, it forces you to look at alternatives that might offer benefits you hadn’t considered.

  • Wall-mounted panels turn unused vertical space into a power plant, offering excellent winter performance and easy maintenance.
  • Ground-mounted systems provide the ultimate in efficiency, allowing you to bypass architectural limitations and position your panels for maximum exposure.

By exploring these options, you ensure that you aren’t just installing solar panels; you are installing the right solar solution for your unique property. Whether on the ground or on the wall, the sun’s energy is there for the taking.

For more detailed information on vertical solar panels check out our blog Wall Mounted Solar Panels: Are They Right for You?

The good news is that you usually don’t need Planning Permission to install solar panels.

Most residential properties classify solar panels as “permitted development,” allowing you to install them without formal planning permission. However, there are some conditions and exceptions to be aware of:

  1. Roof-Mounted Panels:
    • Panels should not protrude more than 200mm from the roof surface.
    • They should not exceed the highest part of the roof (excluding chimneys).
    • Install panels in a way that minimises their visual impact on the building and surrounding area.
  2. Ground-Mounted Panels:
    • The system should not exceed a certain height (usually around 4 meters).
    • Place panels within the property boundary and avoid positioning them in front of the principal elevation of the house (the side facing the road).

Exceptions Where Planning Permission May Be Required

  1. Conservation Areas or Listed Buildings:
    • If your property is in a conservation area, national park, or is a listed building, additional restrictions may apply. You may need to seek permission to ensure the installation does not affect the character of the area or building.
  2. Large-Scale Installations:
    • If you plan to install a large solar array, such as for a commercial property or a ground-mounted system covering a significant area, you will likely need planning permission.
  3. Flat Roofs:
    • If you install panels on flat roofs and raise them significantly above the roofline, you may need permission.

What Should You Do?

  • Check Local Regulations: Always consult your local planning authority to confirm the rules in your area.
  • Hire a Professional Installer: Reputable solar installers are familiar with local regulations and can guide you through the process, including applying for permission if needed.

By ensuring compliance with planning regulations, you can avoid potential fines or the need to remove your solar panels after installation.

For more detailed information check out our blog Do You Need Planning Permission for Solar Panels in the UK?