What size solar & battery system would I need to get credit from my power company all year around?

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To maximise energy bill credits in Australia, households need to produce enough solar electricity to cover their daily power needs and export surplus energy to earn feed-in tariff (FIT) credits. This requires an optimised solar and battery system.

By using solar power during the day (40% of total consumption) and storing excess energy in the battery for the evening, homeowners can reduce grid reliance. To offset daily service charges, exporting around 17kWh per day is necessary. Considering charging losses, a solar system should generate about 40kWh daily for desired results.

Net metering regulations, monitoring system performance, and location's solar potential are essential factors to consider. Customising the system to individual needs and obtaining quotes from reputable installers can increase the chances of receiving credits year-round.

How to get credit from your power company

For many households in Australia, it will take a lot of work to get credit on your energy bill annually. To do so, you would need to produce enough electricity to meet the home’s needs for power daily AND export enough electricity to earn feed-in tariff credits to offset the fixed daily service charges. You also need a solar and battery system that maximises your ability to produce and store electricity.

The same size system will depend on your usage patterns and requirements

Let’s quickly look at a typical flat-rate residential electricity plan. There are charges per kWh for electricity consumption and service charges per day. While rates and costs vary across the country, we will assume that we have a home that has a daily consumption of 18kWh consumption per day on average. Of this total, we will say 40% is used during sunlight hours.

The home’s average daily power bill without solar would look like this:

Daily consumption of 18kWh @ 30c per kWh = $5.40

Daily service charge 85c per day= $0.85

This means daily charges = $6.25

The bill would be $568.75 per quarter.

If the home consumes 40% of its energy during the day, it can directly use 7.2kWh of solar-generated electricity. The remaining 60%, equivalent to 10.8kWh, is required in the evening. To meet this demand, the battery can be used for charging and storing excess solar energy during the day. This makes it available for use during the evening hours. By doing so, the home can rely on the stored energy from the battery to cover its energy needs during the night. This reduces dependence on the grid and maximises the self-consumption of solar power. To cover the daily service charge of 8c per day, you would need to earn 85c per day. Assuming a FIT of 5c per kWh, we would require an additional 17kWh per day to be exported to the grid.

man looking depressed at energy bill

So how much energy do I need?

For the case scenario above, you would need a solar system that produces, on average, at least 18kWh for consumption (self-consumption and battery charging), plus 17kWh per day for exports. This gives an average daily generation of 35kWh per day. However, given efficiency losses in charging the battery, you would be looking for at least 10% additional daily to cover charging losses. The minimum possible daily average generation would be close to 40kWh daily.

Based on the above 40kWh per day, the solar system would need at least 10kWh capacity with a battery of at least 12 -13kWh. Unfortunately, it would likely need even more based on seasonal fluctuations and assumptions to ensure a full-year credit.

Other factors that are important to consider

Net metering 

Research your power company’s or the local government’s net metering regulations. With net metering, you can give the grid any extra electricity you create in exchange for credits. Be aware of the local net metering laws and regulations to guarantee that you will benefit from the credits.


After establishing your solar and battery system, it’s crucial to check its performance regularly. To spot potential problems or inefficiencies, check energy usage, battery storage capacity, and electricity production. The best system performance can be ensured through routine maintenance, such as cleaning solar panels and checking the condition of the batteries.


Your location’s exposure to sunlight is essential for determining the size of your solar system. Solar irradiation varies by climate, which impacts the performance and output of solar panels. Study solar radiation charts or contact nearby solar contractors to find out your region’s solar potential.

In summary

Remember that the specifics of your solar and battery setup will vary depending on your situation. The size and layout of your system will rely on several variables. These include your location and desired level of energy independence. It is advisable to obtain several estimates from reliable installers to compare choices and choose the best option for your needs.

You may raise your chances of receiving credits from your power company all year by investing in a solar panel array of the right size, adding a battery storage system, maximising energy efficiency, and remaining informed on net metering rules.

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