⚡ Optimisers help to maximise a solar panel’s output

🌳 Solar panels already have technology to help them deal with partial shade

📈 Optimisers increase the cost and complexity of your system

💷 Microinverters are generally better than optimisers, but cost more

🛠️ Either of these products can fix multiple issues that reduce your output

When you’re getting a solar panel system, you want it to produce as much electricity as possible, so you can maximise your electricity bill savings.

But if your system is partly shaded, you may need to turn to solar panel optimisers, which manage each panel individually and improve their performance.

In this guide, we’ll explain how optimisers work, their pros and cons, and which households should seriously consider getting them.

If you’re wondering how much you could save with a solar & battery system, enter a few details below and we’ll generate a quick estimate.

What is a solar panel optimiser?

A solar panel optimiser is a small box that connects to a solar panel and tracks its generation, then alters the panel’s electrical characteristics to make sure your system produces as much electricity as possible.

It achieves this via Maximum Power Point Tracking (MPPT), the same technology used by string inverters to maximise a system’s generation.

If your installer recommends that your system needs optimisers, this will mean getting one fitted to every solar panel that could suffer reduced output – for example by being in shade – to ensure they don’t affect how much electricity the rest of your system generates. 

Or, depending on the brand of optimiser you go for, you may need to get one for every panel – even the ones that aren’t expected to experience any output loss.

You should be able to monitor your system’s performance via your solar panel app, and see whether your optimisers are working properly – or whether you need to add some.

Solar panel optimisers work by rerouting the electric current flowing through your solar panel system around panels that are underperforming.

If a small amount of shade falls on one of your panels and temporarily reduces its output by 10%, it can cut your entire system’s generation by 10% – unless you have an optimiser on that panel.

This is because solar panel systems are usually wired in series, meaning every panel’s positive terminal is wired to another’s negative terminal. This raises the system’s output, but means that a drop in one panel’s production levels is replicated across every panel.

When a solar panel’s output falls because of shading, its optimiser can take it out of series and put it in parallel, meaning the shaded panel can still continue to produce its lesser contribution, and the other panels won’t be brought down to its level.

This is an invaluable service, but it’s only necessary in certain situations, as your solar panels already have an in-built solution to partial shading: bypass diodes.

Manufacturers will usually include three bypass diodes per panel, and they’ll each monitor one third of the cells in that panel. If shading affects one of these areas, the relevant bypass diode will reroute the current around that section.

This means you’ll miss out on that section’s solar-generated electricity until it’s unshaded again, but it’s a small price to pay for keeping the system’s current level as high as possible.

Bypass diodes also protect your solar cells from damage, since a panel in the shade can actually overheat and break.

Ideally you’d want a bypass diode for every cell, as this would maximise your system’s output, but the cost would be prohibitive. Three per panel is the practical, cost-effective compromise made by most solar panel manufacturers.

However, bypass diodes generally only step in when 20% of their section is under shade.

So if 15% of your panel is under shade, but it’s spread across three bypass diode areas, it will lower the entire system’s output by 15% – and your bypass diodes will do nothing.

This is where optimisers come in. They’ll leap into action whenever they sense even a little bit of shading, so your system can always work to its maximum level.

<center><em>Optimisers can help you maximise your system's output</em></center>

How are solar panel optimisers installed?

Solar panel optimisers are usually installed on the back of your solar panels or on the mounting brackets they sit on.

Each optimiser will be secured in place within easy reach of a panel, as they must be close enough for an installer to connect the two without using extension cables.

After the installer has connected every optimiser’s cables to its panel and the inverter, they’ll check that the voltage is correct and everything is functioning as it should.

It’s a relatively simple process that usually forms part of a solar panel system installation, though they can also be retrofitted later on.

The exact installation process will also depend on which brand of optimisers you buy – for instance, Tigo’s optimisers have extra wiring and communication needs.

SolarEdge, however, requires you to get a specific SolarEdge inverter, and to have optimisers fitted to every panel, rather than just the ones that experience shading.

To find out how much you could save with a solar & battery system, enter a few details below and we'll generate an estimate for you. 

The pros and cons of solar panel optimisers

Optimisers can increase the amount of electricity your system produces while also raising its price, so it’s important to perform a cost-benefit analysis before you commit.

It also helps to ask one of the best solar installers around – like us – to inspect your rooftop and estimate whether any of your panels will require optimisers.

It’s also worth considering other technologies that let you track and maximise your panels’ output, like microinverters – which a good installer will do too.

You can prevent a partly shaded solar panel from affecting your system’s overall output. A system that suffers from diffuse or partial shading could produce much more electricity with strategically placed optimisers.

They can add to your savings and earnings. If your panels produce more electricity, you’ll need to import less from the grid, and you can sell more to the grid through an export tariff.

You can monitor the performance of every panel that has an optimiser. If all your panels are connected to an optimiser, you can easily diagnose the issue if your system’s overall output ever drops dramatically.

Homes with solar panels on multiple roofs can use optimisers to maximise output. Solar panel systems that are spread across three roofs will struggle to produce as much electricity as possible with a string inverter. Optimisers can solve this issue – though microinverters can too.

Optimisers maximise output even as your solar panels degrade or get dirty. Solar panels lose a tiny amount of output every year, but even in the same system, they’ll usually degrade at different rates. The same is true of dirt – it accumulates on panels to different levels. Optimisers use MPPT to combat this, so each panel will function at its highest possible level.

It adds to your upfront cost. Every extra optimiser bumps up your overall price, with some costing roughly the same as the panel it’s attached to.

Optimisers’ panel monitoring isn’t as sophisticated as it could be. Microinverters monitor your panels’ output in a more dynamic, detailed, and up-to-date manner.

They increase the complexity of your system. Solar panels require a limited amount of maintenance, but installing optimisers means more electrical gear on your roof, and so increases the chance of something going wrong.

Does your solar PV system need optimisers?

Your solar panel system may need optimisers if it often falls under diffuse or partial shading, whether from a tree, chimney, or weather vane.

Without optimisers, any shade could drastically impact your system’s output, as other panels will only be able to produce the same amount of electricity as the affected panel.

In this case, optimisers will allow you to separate the shaded panel from the rest of the panels, and allow the unaffected ones to go on generating as much electricity as they can.

However, solar panels are already fitted with bypass diodes – typically three – which each perform the same function once shading on their section of the panel reaches 20%.

If you have solar panels that face more than two compass directions – for instance, if they face south, west, and east – then a regular inverter won’t be able to handle it well, and your output will suffer as a result. Optimisers can solve this issue.

However, in all these scenarios, a solar panel system in need of optimisation is better off with microinverters – even if they are more expensive. We’ll go into more detail about microinverters later in the article.

You don’t need an optimiser on every solar panel, strictly speaking – but it does allow you to monitor your entire setup and maximise your output.

If you know some of your panels will be affected by diffuse or limited shading, you can only add optimisers to those, but this will leave you unable to address any issues with the others.

And over the years, as they degrade and accumulate dirt, it’ll be increasingly helpful – and profitable – to be able to monitor and automatically adjust all your panels.

Some brands, like SolarEdge and Huawei, only offer solar packages that come with an optimiser for every panel.

However, other companies including Tigo allow you to only attach optimisers to panels affected by shading.

Tigo does recommend that customers buy an optimiser for every panel, but leaves the final decision up to you – making it a potentially more cost-effective option.

<center><em>A solar panel system in need of optimisation is usually better off with microinverters</em></center>

How long do solar panel optimisers last?

Solar panel optimisers generally last around 20-25 years.

That’s why brands like Tigo and SolarEdge’s optimisers come with 25-year warranties, which is also relatively standard for solar panels.

This theoretically means your optimisers should need replacing around the same time as your panels, though in reality, panels can function perfectly well for up to 40 years.

As long as your panels are still working properly, it’s usually worth replacing optimisers that have reached the end of their lifespan.

Doing so is potentially more important as your panels degrade, since larger gaps can open up between individual panels’ performances. With optimisers, you can monitor your panels and get the most out of them throughout their decline.

Do solar panel optimisers require any maintenance?

Solar panels optimisers don’t typically require any maintenance, though like any electrical product, they can experience issues.

Adding any extra items to your system will increase its complexity and the chances of something needing maintenance, and this holds true for optimisers.

If you do get optimisers, check that your warranty includes repairs and replacements if any of them break down.

Fortunately, if you’re regularly monitoring your panels, any optimiser faults should be easy to spot, as you’ll have a decent idea of what outputs to expect from them.

Solar panel optimisers vs microinverters

Microinverters convert each solar panel’s DC electricity to AC, meaning they can replace your string inverter and negate any need for optimisers.

They give you all the monitoring benefits and automatic adjustments that optimisers provide, while offering a number of additional advantages.

Microinverters enable you to add more panels to your system at a later date, even if they’re a different model, size, or brand. All you’ll need is more microinverters.

If you have optimisers however, you may need to get a new string inverter to suit the system’s upgraded capacity, which can be a more difficult, costly process.

Microinverters also fare better than optimisers in low light, since they can start producing electricity with just 20-30 volts. String inverters require at least 60 volts, and usually closer to 200 volts – even with optimisers.

In terms of safety, microinverters are also the better choice, since they perform electricity conversions at each panel. This means there’ll be no high-voltage DC running from your system to your inverter – unlike a setup with a string inverter and optimisers. 

Microinverters are generally better than optimisers, but are usually around three times more expensive.

However, you’ll save by not needing to buy a string inverter, and you may generate more electricity than you would with optimisers – meaning it could be worth it in the long run.

Are solar panel optimisers worth it?

Solar panel optimisers are only worth it if they save you more money than you spend on them – so this calculation should form a crucial part of your decision-making process.

All optimisers have operating power losses, meaning that to stay on, they use about 2% of the electricity that your solar panels generate.

Your installer should work out how much extra electricity optimisers will squeeze out of your panels over their lifespan, enabling you to make a proper comparison.

If your system would only experience shading for part of each day and only on a small number of panels, it may not be worth the cost.

Optimisers will also add to the complexity of your system, and increase the number of electrical items that can break and require maintenance. This can be expensive for rooftop systems, especially as your optimiser warranty probably won’t include scaffolding costs.

Solar panels already come with bypass diodes that do a pretty good job of managing your system’s output under partial shade, so they don’t generally require optimisers.

If we think your system could benefit from optimisation, we’ll recommend it, though we usually prefer to install microinverters, as they’re superior to optimisers in all the ways we’ve explained above.

Solar panel optimisers: FAQs

Do you need optimisers on all solar panels?

What does an optimiser do on a solar panel?

Where are solar optimisers fitted?

What is the warranty of optimisers vs microinverters?

Solar panel optimisers: are they worth it? [UK, 2025]

What's in this guide?

Solar panel optimisers: the expert guide

Selling electricity to the grid: at a glance

💷 Solar export tariffs pay you for all the electricity you send to the grid

⚡ You'll export around 34% of the electricity your panels generate

🔋 You'll typically also need a battery to qualify for the best export tariffs

📃 Most solar export tariffs are available to anyone – but you may need to become a customer first

Solar panel systems can save you hundreds of pounds on your energy bills every year – but even with a solar battery, you’ll always generate more electricity than you can use.

That’s where solar export tariffs come in, to pay you for all the electricity you send to the grid.

In this guide, we’ll go through all the requirements of signing up for a solar export tariff, every step of the process, and how much you can expect to earn.

If you’re interested in how much you could save with a solar & battery system, answer a few quick questions below and we'll provide you with an estimate. 

What is a solar export tariff?

A solar export tariff pays you for all the electricity you send to the grid.

At first, solar export tariffs were created in response to the government launching the Smart Export Guarantee (SEG) in 2020.

This initiative compels energy suppliers with 150,000 customers or more to pay households for any renewable energy – including solar electricity – they export to the grid.

But some companies have now released solar export tariffs that are more profitable than other SEG rates, making them the best export tariffs around.

How much you’ll get paid by a solar export tariff primarily depends on two main factors: how many kilowatt-hours (kWh) of electricity you send to the grid, and the rate you sign up to, which will be measured in pence per kWh.

A typical UK household can earn £361 per year from exporting their excess solar electricity.

This figure is based on a home using 3,400kWh of electricity per year (which is the UK average) with solar irradiance of 850kWh/kWp, a 4.4kWp solar PV system, and a 5.2kWh battery. The home is signed up to E.ON’s Next Export Exclusive tariff, and exports 65% of its solar electricity.

🤔 Thinking of going solar? Here's why a larger system makes sense ⬇️

What are the requirements for a solar export tariff?

To sign up for a solar export tariff, you’ll always need to have a smart meter, as well as documents that prove you own a certified, permitted solar installation.

Some suppliers require you to own a specific brand’s solar panels or battery – usually their own – while others only offer their highest rates to customers in certain geographical areas.

And while you’re free to export your solar electricity to a different supplier from the one you import your electricity from, companies generally only make their best export tariffs available to their own import customers.

Here’s everything you may need to qualify for a solar export tariff:

A document showing your system is certified under the Microgeneration Certification Scheme (MCS) or Flexi-Orb

Proof that you own your solar panel system

A successful G98 application if your inverter capacity is 3.68 kW or less, or

A successful G99 application if your inverter capacity is more than 3.68 kW

A single-line diagram or schematic of the system

How do you sign up for a solar export tariff?

Once you have a smart meter and a solar installation that’s been certified by either the MCS or Flexi-Orb, you’re ready to sign up for a solar export tariff.

Just follow the steps below, and you’ll be receiving payments before you know it.

Solar export tariffs used to be quite tricky to sign up to, but the market has moved on a lot, and in most cases there are now only a couple of documents you need in order to sign up (which we provide for you). It usually takes a couple of weeks for the supplier to complete your registration, then you’ll be ready to start exporting and earning.

The first step is to go through all the best export tariffs, and decide which of the highest-paying rates suits your household.

If your chosen solar export tariff requires you to move to a different electricity supplier, you’ll need to complete the switch before applying for that provider’s export tariff.

Customers who decide to receive an export tariff from the supplier they currently receive their electricity from won’t have to go through this process – but may lose out on savings.

Most export tariff suppliers have online applications, while others require you to email your completed form.

You’ll have to send a list of documents, either with your online application or just after submitting it. These files will vary depending on your supplier, but they can include:

Photographic proof you have a smart meter

A recent electricity bill / other proof of address

Proof that you own the solar installation

A schematic or single-line diagram of your system

Proof that your DNO has approved your G98 or G99 application

Your bank details, if you don’t already receive your electricity from the supplier

Once you’ve completed that process, you just need a smart meter, a system with solar panels and a compatible brand of battery.

3. You or your export tariff supplier will contact your DNO

Within around two days, your export tariff supplier will process your application.

At this point, either you or your supplier should contact your Distribution Network Operator (DNO), which is the organisation that runs the hardware supplying electricity to your region.

The DNO will then supply your property with an export MPAN (Meter Point Administration Number) – a unique, 13-digit number that identifies your electricity meter.

This usually takes a DNO between one and four weeks, and is typically the longest stage of the sign-up process.

Around five days after your DNO creates your MPAN, your supplier will ask for a first export meter reading, usually along with a photo to prove the reading is correct.

You can find this information on your smart meter.

If it’s not clear how to access your export data, just ask your export tariff supplier to walk you through the process.

Once your supplier has verified your reading, all you have to do is sit back and wait for the savings to start rolling in.

Energy companies pay export tariffs at different intervals, though. While Octopus sends your revenues on a monthly basis, OVO and Good Energy pay out every three months, and E.ON only does so once per year – unless you specifically request quarterly payments.

The first payment you get will usually be backdated to when you sent off your application for the tariff, so don’t worry: you’ll be paid for all the electricity you export in the meantime.

Can you access other earnings on top of an export tariff?

You can access some other earnings on top of an export tariff.

Firstly, you can use your solar panels as efficiently as possible. If you don’t have a solar battery, this means using your appliances – like a washing machine, dishwasher, or oven – during the daytime, when your system is generating electricity.

If you do have a battery, but you’re on a standard export tariff without time of use pricing, you’ll simply want to ensure you use as much of your solar electricity as possible, as this will be more valuable to you than exporting it.

Almost all major energy suppliers have also signed up to the Demand Flexibility Service, run by the National Grid Electricity System Operator, which offers customers financial rewards for using less energy at peak usage periods in winter.

Households can register for this programme through their supplier – and if you have a solar & battery system, it’s relatively easy for you to profit (to the tune of around £3 per kWh).

This scheme is a type of virtual power plant. To learn more, read our guide on the topic.

Summary

Signing up for a solar export tariff is the best way to profit from the excess electricity your solar panels generate.

If you choose one of the top tariffs, you can make hundreds of pounds by selling electricity you weren’t going to use anyway – and help make the grid greener.

And as long as you follow our simple steps, the process should be quick and straightforward.

If you would like to see the savings you could get from a solar & battery system, answer a few quick questions below and we’ll provide an estimate.

Here's how exporting solar energy to the grid works, how to sign up for an export tariff, and how much you can expect to earn.

Selling electricity back to the grid [UK, 2025]

Selling electricity back to the grid: the expert guide

✂️ A solar & battery system can cut your annual electricity costs by 86%, on average

📈 Solar panels can increase a home’s value by 3%

💷 The upfront cost is £9,000 for the average three-bedroom household

🏡 Most houses are suitable for solar panels

📅 They work all year round

It’s important to weigh up the benefits and drawbacks of getting solar panels, as you would before any home improvement.

As well as the financial elements, it’s also worth considering their environmental impact, how much they’ll add to your property’s value, and what the planning process will be like.

In this guide, we’ll run through all of these pros and cons and more – and explain how you can make the most of your system while avoiding the biggest pitfalls.

If you would like to see the savings you could get from a solar & battery system, answer a few quick questions below, and we’ll provide an estimate.

What are the advantages and disadvantages of solar panels?

Solar panels, like any source of energy, come with upsides and downsides.

Fortunately, there are many more upsides – as you’ll see below – and most households can easily avoid the downsides.

The upsides are also excellent – among the many positives, you can save hundreds of pounds per year, cut your carbon footprint, and potentially increase your home’s value.

There are numerous advantages to going solar, because it’s a source of free, green electricity that often lasts upwards of 30 years.

Here are all the best benefits to getting solar panels.

Solar panels generate electricity that you can use in your home, which reduces the amount of electricity you have to buy from the grid. This cuts your electricity bills, and if you get a solar battery too, you can save even more.

On average, you could save 86% on your electricity bills with a solar & battery system.

This might sound too good to be true, but it’s all because of the high performance of modern solar panels and storage batteries, as well as export income. The panels will dramatically reduce the amount of electricity you buy from the grid, and you’ll also earn money by selling your unused electricity to the grid.

This is based on a sample of over 150 systems installed by Sunsave across England and Wales in 2024. The average system is 6.1kWp, with 54% of solar electricity used at home and 46% exported to the grid.

The electricity your system generates and stores can also power heat pumps and electric vehicles, which means you can use your panels to slash your heating and driving costs too.

Solar panels cost thousands of pounds if you pay upfront, so it’s only right that they substantially lower your energy bills.

2. You can sell excess energy to the grid

You can earn hundreds of pounds per year by sending the excess electricity your solar panels produce to the grid.

There will be times, especially during summer, when your panels generate more electricity than your home can use and your battery can hold.

This electricity will automatically be sent to the grid – but if you sign up to a solar export tariff, you can gain some profit instead of giving it away for free. All the major electricity suppliers offer export tariffs – often called Smart Export Guarantee rates – but they vary enormously, from 1p per kilowatt-hour (kWh) to above 20p per kWh.

This figure is based on a home using 3,400kWh of electricity per year (which is the UK average) with solar irradiance of 850kWh/kWp, a 4.4kWp solar PV system, and a 5.2kWh battery. The home is signed up to E.ON’s Next Export Exclusive for export, E.ON Next Drive for import, and exports 34% of its solar electricity.

To learn more about how much you can earn, check out our guide to the best export tariffs.

If you signed up to the Feed-in Tariff before it closed to new applications in 2019, you’ll still receive export payments from that scheme, unless you switch to an export tariff.

Solar panels are a clean and renewable source of energy, meaning they don't produce any harmful emissions.

By using solar panels, you can therefore reduce your carbon footprint and help the planet.

Here are all the pros and cons of solar panels, plus how to make the most of your system while avoiding the biggest pitfalls.

Josh Jackman

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