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Can you add more solar panels to your system?

There can be several reasons to expand your solar panel system, maybe your electricity needs have changed, or your family has grown and you need your electricity to supply to match. Adding more solar panels to your system will increase the amount of energy your home produces, and if you have extra space on your roof, installation can be a relatively simple process.

There are some considerations you will need to make before adding more solar panels to your system, so we’ve detailed the things you’ll need to take into account before you commit.

Check your current solar panel system

Before determining whether you can add more solar panels to your system, it is a good idea to make an assessment of the performance of your current solar panel setup. Depending on the age of your current system, increasing the amount of solar panels on your home may come with fitting or cost implications. The team from Project Solar will be able to help you with any questions you have, but it’s good to have some knowledge of your existing system ahead of making changes.

Know your inverter size

An inverter is a device in your solar panel system that converts DC power from your solar panels into AC power for use in your home and the national grid. When solar panels are first fitted, the inverter will be sized according to the amount of solar panels you have, this is normally between 80-120% of the maximum load. By adding more solar panels to your system, you will need to check your existing inverter can handle the additional energy passing through it. You may need to increase the size of your inverter, or another option is to purchase a completely separate inverter for the additional solar panels.


Your feed-in tariff

Feed-in tariffs are designed for solar users to be able to sell back any surplus energy back to the grid. It’s important to note that the feed-in tariff you receive for any additional solar panels you install will be paid at today’s rate, not the rate you initially received when you first fitted your solar panels. The rate today for a feed-in tariff is currently 12.92p but this rate is likely to reduce in the future, so worth bearing in mind if you are debating whether to add more solar panels to your system straight away, or in the future.

Current energy use

Ahead of deciding to add more solar panels to your current system it is important to make an assessment of your current energy use. From here, you can decide the number of panels to add to your system and whether it is a cost-effective decision. If you are currently exporting a large percentage of your energy as surplus back to the grid, your current solar panel system may suffice.  Once you’ve determined your energy use, you can calculate the amount of additional panels you require.

Planning for additional solar panels

Increasing the amount of solar panels isn’t solely determined by how much space you have remaining on your roof. The size of the panels you currently have installed will impact whether you can add more to your system. If your new installation means the energy your solar panel system generates stays below 3.68kW (16 amps), you will be able to continue with no issue.

If adding your new solar panels generates more than 3.68kW of energy, you’ll need to submit a G59 application form to the Distribution Network Officer (DNO). This will determine whether the increased size of your system can operate within the existing grid framework. You will need confirmation of the permission ahead of any fitting. Be wary that this can be quite a lengthy process, and can take several months to receive a response.

How many additional solar panels do you need?

This will depend on the amount of additional power required and the amount of power your current solar panel system produces. Ideally, you’ll use the same panels as your current system, but if the exact panels aren’t available, aim to install panels with the same power rating that your existing panels generate.

Consider purchasing solar batteries

While adding more solar panels to your system, you can also increase your energy efficiency by purchasing solar batteries. Solar power batteries work by storing excess energy generated when it’s sunny and keep it available to use at night or during storms.

Solar power batteries also enable grid trading over a platform such as Social Energy. This allows you to sell or trade surplus energy back to the grid, meaning you can save and earn money on your electricity bills.

Check your figures

Ensure the investment of adding more solar panels to your system works for you. There needs to be both an increase in energy to your home, and a monetary benefit from any additional solar panels you install. It’s recommended to add a minimum of 1kW of additional energy to ensure the financial return from the additional panels (taking into account energy savings and feed-in tariff payments). To do this, you’ll need enough roof space leftover to make the additions. It’s also worth checking the stability of your roof before adding any more.

Talk to the professionals

Deciding whether to add more solar panels to your system can be a big decision, and you want to ensure you will receive the right return on your investment. Our team of friendly experts at Project Solar UK will be able to help you, no matter how far along you are on your solar journey. Get in touch with us today.