How to upgrade your Feed In Tariff solar system
A complete guide to upgrading your Feed in Tariff system while safeguarding your payments.
If your solar system was installed under the Feed-in Tariff (FIT) scheme, you’ll be receiving payments for every unit of electricity your system generates. But technology has advanced significantly since FIT ended in 2019, and many homeowners are now wondering: Can I upgrade my system without losing my FIT payments?
In this article, we’ll explain your options for upgrading your FIT-registered solar system, covering inverters, solar batteries and adding extra panels, all while ensuring you stay compliant.
What are the benefits of upgrading your FIT solar inverter?
Most FIT systems were originally built with string inverters – a simple, lower-cost design where all panels are connected in a single chain. If one panel is shaded, dirty, or faulty, the output of all of the panels within the string will be impacted.
Since FIT payments last for 25 years, and string inverters typically only last 10–15, it’s likely that the inverter will need to be replaced at some point.
Here’s why we recommend upgrading to a SolarEdge optimised inverter:
Higher efficiency and greater savings: An optimised system can extract more energy from the same number of panels, leading to greater financial savings.
Panel-level optimisation: Each panel works independently, so shading, dirt, or a faulty panel won’t drag down the whole system.
Panel-level monitoring: You and your installer can monitor the output of each individual panel, making it easy to spot and fix performance issues.
Longer lifespan: Unlike string inverters, SolarEdge operates at a fixed DC voltage, which typically extends the life of the inverter. It comes with a 25-year optimiser warranty and a standard 12-year inverter warranty, which can be extended to 25 years.
Our customer had their original system installed in 2013 through the Feed in Tariff. It generated around 2,350 kWh a year.
We upgraded their inverter with an equivalent sized SolarEdge inverter with optimisers. The expected annual output is now 3,247 kWh a year.
This is a 897 kWh uplift each year; leading to approximately £650 a year in additional FIT payments and energy savings.
How do I keep my FIT payments while upgrading my inverter?
Following Ofgem’s guidance, you can upgrade your inverter, including to a new inverter with a larger capacity, as long as you have permission from your FIT provider. This means, for example, that you can replace an old 3kW inverter with a 5kW inverter and keep your FIT payments. If you choose Good Energy to carry out the work, we’ll help you gather all the necessary documentation for your FIT provider.
If Good Energy is your FIT provider, we’ll need:
- The declared net capacity of your new inverter, and the capacity of the one it’s replacing
- The size increase of the inverter (eg from 3kw to 5kw)
- A commissioning certificate, invoice, or installer’s note confirming what was installed
Important! Make sure you get permission from your FIT provider before upgrading your inverter.
Can I add a solar battery to my FIT system?
Adding a battery is a great way to increase the benefits of your FIT solar system. However, it must be set up in a way that avoids any double-counting of your generated or exported solar power.
There are a couple of different options when it comes to adding a solar battery to a FIT registered system. Our expert team can support you to make the best decision for your needs and your home:
AC-coupled batteries (e.g. Tesla Powerwall 3): Easy to integrate with FIT systems; installed after your generation meter with its own battery inverter.
DC-coupled batteries (e.g. SolarEdge Battery): More complicated to integrate with a FIT system, but possible, particularly if you are replacing your inverter at the same time. Requires a hybrid inverter and a bi-directional meter providing a net reading to track your generated and exported solar power accurately.
Important! If you’re considering adding a battery, you’ll need to inform your FIT provider and send them a diagram of your proposed system layout to safeguard your payments.
Can I add more solar panels to my FIT solar system?
According to Ofgem, you can add more solar panels or replace your existing panels with new ones, as long as you have the permission from your FIT provider.
If you increase the size of your system, you will receive FIT payments for a percentage of your overall generation and export (for example if you increase your system from 4kW to 5kW, you will be paid FIT rates for 80% of your generated power).
While you’re having work done, consider adding bird-proofing to prevent nesting under the panels, to safeguard your wiring and system efficiency.
Important! You need to discuss your planned changes with your FIT provider before going ahead to ensure compliance with their understanding of Ofgem’s rules.
Can I upgrade my FIT export payments?
Many homeowners are surprised to hear that they could be earning more from their exported electricity, while still receiving their FIT generation payments. On average, customers earn 5-7p per unit through FIT export payments, and up to 15p if they switch to an export tariff.
How can I avoid being scammed when upgrading my solar panel system?
Unfortunately there are a number of scams targeting homeowners with solar panels. To keep safe:
Use an MCS certified installer: This ensures your installer meets industry standards and your upgrades are properly documented.
Never sign anything under pressure: Don’t agree to work over the phone or at your door. A reputable installer will give you time to review your options and compare quotes.
Do your research: Check company reviews, ask for case studies, and make sure all paperwork is in order before any work begins.
Speak with your FIT provider: If it’s Good Energy, we’re very happy to talk you through your options for upgrading, while keeping your FIT payments.
Conclusion: Is upgrading your FIT solar panel system worth it?
With the right approach, upgrading your inverter, adding panels, or installing a battery can significantly improve your solar system’s performance, helping you to earn more money from your FIT and make greater energy bill savings at home too.
Our expert, friendly team can help you decide what’s right for your home.
