Solar & Battery Storage Solution

March 20, 2020
P4B Solar
Tesla Powerwall Battery - Adelaide Solar

With the SA state governments recent announcement of the Home Battery Scheme rebate decrease, there are lots of questions about what is happening with the battery storage space.

A lot of people are waiting for technology to improve; a lot of people are waiting for a large price drop as happened with solar system materials in the middle of the last decade; some just don’t see the need for batteries – and rightly so. Energy Storage Systems are not suitable for all households for several reasons, but they are suitable for a lot of households as they have many benefits.

From primary benefits such as maximising the savings possible from your solar system, or providing potential back-up capabilities in a grid failure.

To ancillary benefits such as grid stabilisation and reduced dependency on environmentally damaging fossil fuel-based energy sources. 

Existing Solar Systems

Now it is important to note that unless your solar system was specifically designed with the addition or retrofit of battery storage in mind, it is likely that additional components are required to connect your system to an Energy Storage System.

This could mean an interface module to allow your existing inverter to communicate with the battery storage unit or a whole new inverter which is capable of processing the energy produced by your solar system into a battery storage format. 

It is important to have this discussion with a qualified installer or CEC Approved Solar Retailer to ensure that you are getting the right information before you spend too much time researching battery brands and sizes – if you need to spend too much money on additional components before you’re even ready to connect a battery, it may not be financially viable for you. 

New Solar Systems 

If you are considering solar and you want to explore battery storage options now, or in the future, it is vitally important that you discuss this with your Approved Solar Retailer or qualified installer to ensure that the system you are paying for will do what you expect it to.

Too often we hear stories of people who have outlay vast amounts of money for a solar system with the expectation of connecting a battery only to be told sometime down the track that their system is not compatible with battery storage and that additional works are required.

Save yourself the hassle and find this out before you go ahead.

All batteries are the same, right?

Battery Wall 1 P4B Solar
An LG Chem RESU10H Battery Storage System combined with a 5kW StorEdge inverter, with back up capabilities.

Not at all!

Much like there are different cars for different uses, different houses for different living situations and different printers for different applications, battery storage capabilities can vary greatly depending on your desired use for it. 

Some batteries such as the LG Chem RESU10H and the Tesla Powerwall 2 will provide you with black-out capabilities, allowing your house to continue to run on essential circuits if the grid blacks out. However, this may only be capable if you have installed the right inverter, gateway or interface.

Again it is vitally important to discuss these desires with your installer before you proceed. Certain inverters will allow a battery storage connection but cannot provide black-out capabilities, meaning that when the grid goes out, so does your house, regardless of the battery storage system you’ve purchased. 

I’ve got three-phase power, what are my options?

Whilst there are some three-phase inverter options which will allow a battery storage connection (look for hybrid in the name as a clear giveaway), but these tend to be fairly pricy options.

The benefit of this is that a 3 Phase inverter will spread power across all three phases, whilst a single-phase inverter connects to just one phase. The most common way to get around this problem is to implement a technology called Net Metering.

Net Metering Explainer P4B Solar
Net Metering explained.

The essence is that a meter connected to the solar system monitors the incoming and outgoing electricity and spreads the solar or battery power across the three phases to ensure maximum efficiency of self-consumption

In the case of a black-out, assuming your system has black-out capabilities, your system should be designed and connected to the supply phase which has your essentials on it.

Essentials include lighting for main areas, a water pump, hot water pilot light (for gas systems) or hot water system (be careful as these can draw A LOT of power) and maybe a small emergency fridge to keep your perishables safe.

A qualified electrician should be able to help you calculate the energy draw from each circuit that you wish to back up to work out roughly how long your battery and solar system will keep your household running before going into standby to charge up again. 

Working out my battery storage requirements

Your CEC Approved Solar Retailer or qualified installer should be able to help you get an understanding of your day time vs night time electricity consumption.

If the company you’re dealing with doesn’t have some idea of your day time vs night time use, you should be asking more questions or considering another company. 

There are two arguments here.

Typically residential battery storage systems range from 6-14kWh of storage. Given that Lithium-Ion battery storage units cannot discharge 100% of the power they store, you’re better estimating using 95% of this power in the first year and decreasing gradually to somewhere around 60% of original capacity after 8-10 years (depending on how often you cycle your battery).

Most households will be well suited with approximately 10kWh of battery storage but of course, this varies from household to household. Battery storage is an expensive investment, so unless you need A LOT more power than 1 x 10kWh battery can provide, it may be worth considering changing some of your consumption behaviours to daytime, when your solar system is generating free electricity already.

Most solar systems will export electricity to the grid, earning the owner a feed-in tariff somewhere between 10 and 20 cents depending on your retailer. But the same owner typically pays between 32 and 36 cents for the power they buy from their retailer.

So if you can load-shift some of your usages to daytime and consume that power instead of exporting it, you are saving 32 cents instead of earning, say, 14 cents. Consider load-shifting before investing further.

It is important to note than a reliable monitoring platform for your solar system can help you to work this out as well. 

I am going to wait until the prices drop and the technology improves

There are many people out there taking this approach and we are not going to tell you that you are wrong to do so. That is not our place or our desire.

We get questions about what is happening in the market all the time. What is happening, when is the next big technology shift and when will prices drop? 

Well, new technology is coming out all the time. There are no secrets there.

A start-up out of the University of NSW has developed a technology which utilises a Zinc-Bromide technology encases in a gel compound which allows for the greater discharge of electricity and reduced fire risk (gels are neither liquid nor solid and so are unable to ignite in the same way that solids can). However, the life-span of these is not quite there yet and the product is not yet on the market.

Other companies are trying to resurge lead-acid batteries again. One company we spoke to recently is designing a scalable Lithium Titanate battery storage solution in a sleek column-style design which looks good and boasts a long life-span/maximum cycle-span.

The company is relatively new and so to ensure these warranties they would have likely rapid cycled their battery over a shortened period and extrapolated the data out to provide the product warranties provided.

There is nothing to say that these warranties aren’t accurate and that this product isn’t great, time will tell on that one. 

What we are finding more and more is that the most popular batteries on the market are the LG Chem Battery and the Tesla Powerwall Battery, depending on your willingness to part with your hard-earned cash.

To ensure a battery lasts as long as your warranties claim, you need to have tested this battery to ensure its safety and operational efficiency. This is one of the major hold-ups in the flood of new technology to the market. 

The reason why we are not seeing serious price drops in the battery storage space is the rapid uptake of battery materials in the electric vehicle market. With a new electric vehicle coming out every other day and many of these vehicles utilising more than one battery unit, there is no serious influx of supply – hence no major spike in demand and competition.

The new Tesla Roadster boasts a whopping three battery storage units to provide some serious power and an impressive 1000 km electric range. 

For those of you who wish to wait, you are very welcome to do so.

However, in the meantime, you will still be paying for dirty energy derived from coal and costing you loads. It is no secret that renewable energy is now more cost-effective to generate than coal-fired power. With the right household paying off a battery storage system and solar system together in as little as four years, possibly less for some, there is a strong argument for investing in storage today, not 5 years from now. 

Home Battery Scheme Subsidy – Rebate Decrease

Battery Storage is still a very expensive exercise with many deciding against it, especially in the commercial space where no such subsidies exist. But South Australia has the unique ability to invest in this space heavily under the Home Battery Subsidy Scheme.

Sa Govt Provider P4B Solar

Every ‘Qualified System Provider’ under the SA Government Home Battery Subsidy Scheme is promoting the recently announced rebate decrease.

As of the 15th of April 2020, the rebate will decrease from $500 per usable kWh of storage (for regular energy account holders) to $300 per usable kWh of storage. If you use the LG Chem RESU10H as an example, the current rebate is $4,650 off the cost of your system.

This is around the 50% mark for the cost of a battery installed (granted you have a battery ready solar system with no additional components required).

If you wait until after 15th April 2020, the rebate would drop to $2,790.

This is a whopping $1,860 you’re going to have to find if you want to invest a battery. Whilst it is still nice to get 25-30% off of the cost of your storage unit, it is not 50%. This will drastically increase your payback period and your Return on Investment (ROI).

If your electricity bills are around $1,000 a quarter or more, you need to consider battery storage as an option shortly before the viability of this project decreases massively. 

Contact P4B Solar below if you’re interested in discussing your Household Solar and Battery options.