What’s an Expandable Solar Power System?

Information verified correct on October 26th, 2016

solar-expanderAn expandable system can grow as your solar needs grow and situations change. Invest in solar power and start small.

Getting on the solar power bandwagon is not cheap, but with an expandable system you don’t have to account for all your energy needs in one go.

If you’re considering installing solar power, it’s important to know that you don’t have to invest in a system that takes care of your electricity requirements in total at the very onset. With an expandable solar power system you can always choose to start small, and you can keep adding to the system as your budget permits. You can also opt for an expandable system if you don’t need as much energy now as you might in the future, when your household grows.

How does it work?

You can install a certain amount of panels and leave space for more later if you need them. Your original system will be installed with a solar inverter much bigger than it currently needs, so that in the future you can add more panels without having to change inverters or remake the whole system.

An expandable solar power system, unlike a maximised solar power system, allows you to increase the number of linked panels down the line. Consider this - you may have enough ground space or space on your roof to install, say, a 5 kW system, but you may not be able to invest in more than 3 kW worth of panels. In such a scenario you have the option of installing a larger than currently needed inverter, which gives you the ability to add more panels later.

If you get a 5 kW solar inverter along with 3 kW worth of panels, you can add up to 2 kW worth of solar panels as and when you can afford them.

Is an expandable solar power system expensive?

A 5kW inverter is around the $3,000 mark. Then in the future when you decide to add more panels you will already have the capacity to install them, which will be far cheaper than having to redo your installation and insert a new inverter.  When you opt for an expandable solar power system getting a more powerful invert will require that you spend some extra money. The difference between installing a 3 kW and a 5 kW inverter, though, is nominal at best. If you plan to upgrade to an altogether larger system, consider the time and money you’ll have to spend to install a new inverter, and also take into account that you’ll have to register the new inverter with your utility company.

Inverter size and feed-in tariff

When you install and commission a new on-grid solar power system you have to register it with your energy provider by giving specific details about the new setup. These details include serial numbers, number of panels and capacity of the inverter. The inverter’s capacity comes into play because energy providers use this as a benchmark in arriving at the size of any given system, which tends to have an effect on the feed-in tariff rate.

If you wish to replace your system’s existing inverter with a new inverter, there’s a good chance that you’ll end up terminating the ongoing contract you have with your energy provider, and you’ll then have to sign a new contract with revised feed-in rates.

If you, to start with, install a 5 kW inverter along with 3 kW worth of solar panels, your energy provider will list your installation as a 5 kW system. What this essentially means is if you invest in a larger inverter down the road, there can be a change in your feed-in tariff, but if you get a larger than required inverter to begin with, your feed-in tariff will remain the same until you need an even larger inverter.

Just what effect a new inverter can have on your feed-in tariff depends on where you live. For example, if you live in Queensland, when you installed your solar power system and the intended changes play a role in feed-in rates. If you registered before the 44 cent feed-in tariff cut-off date and make no changes to your inverter but add more panels, you can continue availing the 44 cents feed-in tariff until 1 July 2028, as long as you maintain your eligibility. However, if you change your inverter, you’ll have to forfeit the 44 cents feed-in tariff, and you’ll then be looking at a reduced rate of 8 cents per kWh.

How do I add new panels?

Panels can be added one at a time, or a couple at a time and will be connected to your system. This is a cost effective way to build up to a full solar powered home, or if you need to increase your power as your household or usage grows.

How difficult is expansion?

Building on an expandable solar power system is easy, and you can add more panels as and when possible. What helps is that you don’t have to add them all together; you can keep adding one at a time until you reach the inverter’s capacity. This means you don’t have to stretch your budget at any time, and you can work your way up as per your financial capability.

What other benefits are there?

If you’re considering investing in a traditional solar power system you will have to carry out calculations to arrive at your existing and future energy requirements to make sure you get the right system. If you choose to get an expandable system, you don’t really have to account for future needs because your system can grow with time.

With a traditional system, even the failure of a single panel can lead to stalling of the entire system. With an expandable system, panels work independently, so even if one fails, the others keep the system going. Opting to go the expandable solar power system way is definitely a good idea, especially if you see your needs growing in the future, or even if you can’t afford a big enough system now.

Any other considerations?

There is another bonus that comes with expandable solar. Many energy providers calculate their feed-in tariffs based on the size of the inverter the system has. This means that if you were to install a 3kW inverter now, and later switch to a 5kW inverter your feed-in rate would drop.

However, if you installed a 5kW inverter, your feed-in tariff remains the same while your energy production increases and your solar credits increase. This is a nominal change, but it provides a great incentive to grow your system and to increase your output. However, this will vary state-by-state and depends on which energy supplier you are with.

Solar panel systems are designed to be flexible and to suit your needs, and expandable solar panels are about as flexible as it gets. If you’re desperate to create your own clean energy but are worried about the cost, then why not start small and work your way up?

Shirley Liu

Shirley is finder.com.au's publisher for banking and investments. She is currently studying a Masters in Commerce (Finance) and is the author of hundreds of articles. She is passionate about helping Aussies make an informed decision, save money and find the best deal for their needs.

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