Deciding between keeping or replacing an existing solar system depends on factors like is the system still receiving the "Premium Feed-in-Tariffs" in your State.
If you benefit from these and if your system is larger than 1.5 kW, sticking with your current system might make sense. However, over time, panels and inverters degrade, impacting performance.
Upgrading to newer, more efficient technology can be cost-effective, as modern panels and inverters are significantly better and allow a larger system to supply your home effectively.
Removing the existing solar system can free up roof space for a more efficient installation. You can also claim rebates for the new system and save on costs. Recycling old equipment can not be undertaken. In most cases, scrapping the old system and starting fresh is the recommended course of action.
I have a small 10-year-old solar system. Do I eliminate it, or do I upgrade my existing solar system?
Let’s say you have an existing solar system. You purchased a small system many years ago, in the early 2000s, because around that time a solar panel cost over $1,000, when today panels with double and even close to triple capacity only cost a few hundred dollars. The system served you well and you made money by saving on decades of electricity bills.
Lately, with the ongoing increase in electricity bills, your bill has also become quite high, simply because your existing 2kW solar system does not offset too much of your consumption nowadays. So you have experienced the benefits of solar and you know it works well, but you need more.
Technically one can not add a new inverter to the existing solar system and just add more panels for a number of reasons. Firstly, the panels have changed significantly and are not compatible. Secondly, the technical standards have changed and while your existing solar system is still allowed to run, nothing can be added, and even repairs have to be undertaken in a like-for-like replacement regime.
So there are two clear options:
- Replace your existing solar system and start from scratch with most likely a much larger system ;
- Leave your existing solar system as is and add a brand new 2nd system to the mix.
Option 1: Replacing your existing solar system completely
So let’s say you’ve had your system for ten years. It has performed well to date but is not meeting your needs now. Your family may have grown, use more power, you’re using more electrical appliances, buy an electric car and want to charge it.
But you’re looking at your existing solar system and thinking it’s still performing okay. You were also sold on it having a 20+ year lifespan. So it should still have a lot of life left in it. It seems a waste to replace and scrap an existing solar system. A waste of resources and an investment that you made in this system ten years ago. So let’s examine the pros and cons.
Modern technology has improved solar a lot
Modern solar panels and inverters are more efficient and have higher energy output compared to those from a decade ago. Replacing your existing solar system can significantly increase the energy yield and potentially cover a larger portion of your electricity needs.
Two different PV systems side by side can look ugly
Sometimes the initial installer plonked the solar system right in the middle of the roof, in the easiest-to-access spot. This now means you do now have to place the new panels around your existing solar system creating a patchwork look on your roof. For this reason, many installers recommend replacing the existing solar system and starting from scratch, as the final look of your home should be a consideration.
Changes in technology
New systems come with updated technology, such as improved inverters and monitoring systems, which can provide better performance and easier tracking of energy production and consumption. They also have sexy apps and allow more smooth integration with other energy appliances such as air-conditioning and heat pumps as well as batteries.
Panel and inverter technology has improved a lot over the last ten years. Standard panels ten years ago were 250 watts per panel and were around 14% efficient. Modern panels are up around 430 – 450 Watts and are over 22% efficient. So for the same space, you can produce around 50% more power with the latest panels compared to the 10-year-old ones you have.
Inverter technologies have also improved. Not only are they more efficient (from around 95% to 98% plus), but many now come with 10-year plus warranties instead of the old 5-year warranties. So, by taking your existing solar system off and replacing it with a new system, you will be able to have more power in the same space.
The biggest limitation in installing solar on a roof is often having the roof space available. Quite often, the need to design and install a new solar system around an existing solar system can limit the ability to utilise the available roof space efficiently and make it difficult to install. The roof space is freed up to be a blank canvas so that the largest possible and best system possible can be designed and installed on the roof to service your home.
Longer warranties and lifespan
Newer panels, inverters and racking typically have a longer lifespan and come with fresh warranties, providing peace of mind for the coming decades.
Modern solar panels and setup could offer sleeker designs, and better aesthetics, with black panels and black rails, aligning with the current architectural trends.
How much have panels and inverters degraded in the existing solar system?
Let’s say your existing system is ten years old, and over that time, the production and performance are likely to have dropped. Solar panels degrade over time, depending on the quality of the solar panels on your roof. You may find that over the last ten years, the power you are getting out of the panels has dropped a little (1% or a bit less per year). In some cases, you can even expect cheaper panels to have decreased by more than 10% overall.
The inverter, after ten years, if it hasn’t already been replaced over that time, would be getting to the end of life. Usually, a good quality inverter would last 10-15 years. So if you haven’t replaced the inverter already, more than likely than not, it will need to be replaced in the not-too-distant future. So you could look at a replacement cost of the inverter of $1000, give or take. This would often require additional work at a greater expense to bring the rest of the system up to current safety standards. Which have changed significantly over the last ten years.
Higher initial cost
Replacing the entire system and adding a few more kW in capacity can add a little to the cost, but often it will be less than one might fear. Maybe get pricing for both options and you will be surprised how little extra a larger PV system will cost. However, the higher investment is likely to pay off over time through increased energy savings.
There’s the environmental consideration of disposing of or recycling the old solar panels and inverters, which may not always be straightforward.
Option 2: Leave your existing solar system as is and add a brand new second system to the mix
Increased capacity for a lower cost
By adding a new system, you are essentially increasing the capacity to generate more solar power without losing the value of your initial investment.
It might be more cost-effective upfront as you’re not removing the existing system, but rather supplementing it.
Retaining the existing solar system which might be working perfectly fine is an environmentally friendly option as it continues to produce energy, albeit at a lower efficiency, as panels would have degraded somewhat.
More technically complex setup
Having two systems might complicate the setup, requiring additional space and possibly more maintenance. Also in case you seek to install a DC battery, the solar from the existing system will not be available to charge the battery.
The differing technologies between old and new systems could create monitoring and maintenance inconsistencies and will not allow for the most smooth operation.
The existing solar system will still have its limitations, and over time, might become increasingly outdated, eventually necessitating a replacement. There is no guarantee how long the existing solar system will last, and when it finally breaks down, one has to redesign the setup again.
Are you on one of the old Premium Feed-in Tariffs?
There are still several States across the country that have “Premium Feed-in-Tariffs” in place for solar systems installed ten years ago or so. If you are on one of these in the Northern Territory, Queensland, South Australia or Victoria. It would be worthwhile to look at what you are earning on these. As well as how long it will last and what you will risk now by expanding or replacing your existing system. If the system is 1.5 kW or smaller – replacing is still a good option. If one paid big bucks many years ago and has a 3.5 or 8 kW system on the old feed-in tariff, then there is a lot of Fit lost if one uninstalls the system now. So you may find that it does not make financial sense to take the existing solar system off at this time.
You can also claim the “rebate” or small-scale technology certificates for the entire new system. Even when replacing a system that would have received the rebates ten years ago. Many quality installers also use recycling facilities for panels that are removed. So you can also request that the equipment is recycled to avoid wastage of the panels in a landfill.
So do I scrap my existing solar system?
In most cases, it would make sense to scrap the 10-year-old system and start the next solar system design from scratch. This is because has solar technology significantly increased efficiency and decreased in price. But specific parts of your system will be coming to the end of their life after ten years and for most cases.
It won’t make financial sense to try and repair them. Finally, with the increase in energy prices and the electrification of our homes and vehicles, one can expect their energy costs to increase even further in the near future.