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Writer's pictureJohn Debrincat

Towards Net Zero and Save on Power

Towards Net Zero and Save Power Costs

First Month Experience Solar & Battery

With a heritage house, circa 1860, in a leafy Sydney suburb just 15 minutes from the CBD there could be problems adopting solar. Our home built with stone in the 1860’s then extended much latter has issues when it comes to any renovations or changes. Issues like cabling through stone walls, changes to the style, the look from the street, are all important as are local council requirements. Adopting solar energy is more than just installing panels on your roof; it’s a lifestyle shift towards sustainability, energy independence, and reduced carbon emissions. Our household in Sydney has almost completed the first month of using an 8.5 kW solar panel system paired with a 10 kWh battery, and the results are promising and better than expected.


The Truth, the Whole Truth & Nothing but the Truth

There seems to be a lot of false or misleading information about what system to use and how big it should be. It is important to get the right information and to do some comparison. Ask people you know who have solar for recommendations and feedback. This can help you get on the right track. Ask for quotes based on your home usage and situation. We had quotes that ranged from under $10,000 to over $35,000 for the same infrastructure.


If a company is quoting they need to see the property, the house situation on the property. Areas of shading and obstacles are important, the type of roof, location of power box, types of walls, the current power bill (preferably multiple over time to get some idea of average usage) and access to internet to connect devices. If you are asked to fill out a form online and they send a quote then forget them.

  • Warranty and maintenance are essential, and it needs to be clearly laid out in the proposal and quote.

  • There may be separate warranties on panels, inverters and batteries.

  • Do reference checks on suppliers and check licences and certifications.

  • Be careful of companies that under quote and recommend a system not capable of supporting your home requirements.

  • Be careful with solar comparison websites. There are lots and most are just setup to pass on leads.

  • The power providers like AGL, Origin, Essential and others also provide solar and batteries. They are worth checking out while you do your reviews.


monthly energy consumption graph
First 26 Days Usage in Sydney

After looking at many providers we selected a local company Solar Bright to provide the systems, do the installation and, also importantly, maintenance. They also looked after all the available rebates and government requirements.


The Setup

Our solar energy system is designed to harness Sydney’s abundant sunlight and store excess energy in the battery for use during the evening or overcast periods. With typical daytime energy consumption, the house has a typical daily consumption between 12 - 14 kWh, the system is more than sufficient for most daily needs, except on particularly hot days when the air conditioner, dryer, and dishwasher may push usage up and then the battery will supplement supply or you buy from the grid when the battery runs out. So far we have not yet seen that occur but it is early days.


Cabling had to be external due to the stone walls but the setup is out of site from the road. Of course on more modern homes, or new homes, cabling would not be visible.


solar inverter and power board
Solax Inverter and Signage

The addition of an electric vehicle (EV) charger has also made the setup more dynamic. By charging the EV directly from the solar system, we’re reducing reliance on the grid while enjoying significant cost savings. Depending on using the slow charger (2 kWh) or the fast wall charger (8 kWh), we strategically time our charging sessions for peak solar production hours. So home EV charging is free the majority of the time.


Tesla 8kWh wall charger
Tesla Gen 3 8kW Single Phase Wall Charger

Performance and Adjustments

After the first month, our household has achieved near-total self-sufficiency on normal days. Here’s a snapshot of what we’ve learned:

sonnen 10 kWh battery lithium ion
Sonnen 10 kW Battery

  1. Timing is Everything: To maximise solar usage, we’ve shifted energy-intensive activities like running the dishwasher or doing laundry to sunny hours where possible. While overcast days reduce solar output, there’s always some power generation, where there’s light, there’s power. With thoughtful planning, we’ve kept grid reliance minimal. The system gives between 95% to 100% self-sufficiency. Our power bills were between $250 and $300 per month. The last month bill (which run from mid-month to mid-month) with a full month of solar and 15 days of battery storage (since install) was $30 and will be lower with a full month counted. We installed the solar panels in September and then the Battery 1st November to take advantage of the latest rebates.

  2. Battery Insights: The 10 kWh battery provides a reliable backup during the evenings and overcast weather. On sunny days, the battery can reach full charge before midday, allowing us to use the stored energy through the night. Typically, overnight the battery may use around 50% or more of the charge running household items like TVs, stoves, fridges etc. The energy usage of devices is important so check for the best performer when you buy. If you run your aircon all night, it will probably drain the battery and start using grid power. The apps that are now linked to solar and batteries give you an amazing insight into your power consumption.

  3. Managing High Demand Days: On hotter days, when the air conditioner and other appliances are running simultaneously, we do occasionally tap into the grid. Or similarly on very cold days, overcast and rainy, hopefully not too many of these in Sydney. However, these instances are infrequent and typically occur when energy demands align poorly with solar generation. The maximum production is around 8kWh but if its overcast that will decrease. Solar panels need to be cleaned if you live in a area where trees drop lots of leaf matter etc. Your installer can advise you on the issues that you need to be aware of.

  4. EV Charging: Charging the EV directly from the solar system has been a game-changer. Using the slower charger during sunny periods ensures that most of the energy comes directly from the panels, while the fast charger is reserved for when we have surplus solar production or the car needs to get charged faster.

  5. Feed-in Fees: Excess power will be sent to the grid and for that you get a “Feed-in” fee, in our case $0.05 per kW. This is not a huge amount of money and where the energy providers are doing well. Care is needed when dealing with the energy providers and shopping around can give you gains. The providers will offer increased feed-in fees if pressured but beware as they will often increase the rates for usage at the same time. Some will also cap the feed-in rate for the first say the first 8kW and then reduce it significantly for anything over that amount.


Challenges and Adaptations

Meters and Your Energy Provider

To enable you to use solar and a battery you will need to have a "smart" meter connected to your home. The old meters were analogue, they had a rotating disc and recorded power usage. Monthly or quarterly a meter reader would manually check the consumption for your bill.


These have been replaced with meters that can be read remotely and digitally record the power consumption for your property. Your power provider will need to ensure you have a smart meter and may need to make adjustments to enable solar usage recording.


It is your responsibility to communicate with the power supplier (AGL, Origin, Essential, etc.) and arrange for the correct meter. Replacing a meter, if necessary, may cost money. It may also take weeks to arrange this and have the work performed.


The Weather

One of the key challenges is managing energy use during extended overcast periods or when high demand coincides with low production. We’ve also become more conscious of planning high-energy tasks for sunnier days, which has required a slight shift in daily routines.


One possible solution is to use a battery with larger storage. Costs of batteries can go up steeply as the battery capacity increases. Overall you need to take an holistic view of the impact of poor production days over a longer term.


Battery Health

Another consideration is the long-term impact of battery health and ensuring that our system’s efficiency remains high. Regular monitoring via the system's app has been crucial in identifying patterns and making informed adjustments. The supplier has been very proactive in helping us get most efficient usage.


appliance energy rating information

Appliances and Energy Rating

All modern appliances now come with an energy rating. When selecting a new appliance you can determine which might be best for you by looking for the energy rating for the device. This will normally be a large yellow sticker on the device with a start rating and energy consumption advice. You may find that the best performing product is also a little more expensive but it can lead to great savings as well.


Benefits: Cost Savings and Carbon Reduction

The immediate impact on our power bills is significant. Grid consumption has dropped dramatically, reducing costs and increasing confidence in our journey toward complete energy independence. On sunny days, we’re effectively zero-cost consumers.

Environmentally, the switch has made a tangible difference. By relying primarily on solar power, we’ve cut down our carbon dioxide emissions, contributing to a cleaner and more sustainable future.


daily analysis of data production versus demand
Daily Usage Stats from Sonnen App

Looking Ahead

The first month has been a resounding success, but this is just the beginning. As we continue to fine-tune our usage patterns and explore additional ways to optimise energy consumption, we’re excited about the prospect of complete energy independence even on challenging days.


For anyone considering making the switch to solar, our experience underscores the importance of doing your homework, understanding your energy needs, planning usage around production, and embracing a new way of living. Solar power isn’t just a technology; it’s a step toward a brighter, cleaner future.


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