Why solar power works, even if you use energy at night

Published: 31 August 2021

Going solar is an excellent home upgrade, since your power bills are reduced for decades. However, if your energy consumption is mostly at night, you may be wondering how solar panels can help you save money.

Are you wondering if solar power is worth it if you use most of your power at night?

There are two main things to consider:

  • Your home can become a small-scale power plant during the day, exporting surplus electricity from solar panels to the local grid.
  • You can also add a battery system to your solar panels, to store electricity during the day and use it at night.

When exporting solar energy to the grid, your electricity sales are subtracted from the next power bill. On the other hand, when using batteries, the power meter registers less consumption at night and your bill decreases. Each option has advantages and disadvantages, but both of them achieve the same goal – reducing your electricity bills.

Option 1 – Selling surplus solar power to your electricity provider

When you export solar electricity, the kilowatt-hours provided during the billing period are measured, and multiplied by a feed-in tariff or FIT.  This dollar amount is then subtracted from your power bill.

  • For example, if you export 2,000 kWh and the FIT is 10 cents/kWh, your next bill is reduced by $200.
  • You will also pay less thanks to the solar electricity that is used directly by home appliances. This represents kilowatt-hours that are not consumed from the grid.

Solar feed-in tariffs are convenient if you’re away from home during the day, since you don’t need additional devices to use solar panels. Their daytime production is simply sent to the grid, measured by your power meter, and deducted from your bill. This way, you can save with solar panels even if most of your consumption is at night.

There is one main disadvantage when exporting solar power to the grid. The feed-in tariffs paid by electricity companies are much lower than the kWh prices they charge, especially in Australia. For example, you may find that your kWh price is above 30 cents/kWh, while your FIT is less than 10 cents/kWh. This means that consuming solar electricity results in higher savings than selling it.

Even with the low feed-in tariffs, solar power is an attractive investment. Quality solar panels come with a rated service life of over 25 years, and their payback period is only around 5 years in Australia. If you use a solar loan to finance your installation, the upfront cost is zero and loan payments are covered by savings – in other words, the payback period is also zero.

Option 2 – Charging batteries during the day, using solar power at night

If you don’t want to sell your solar energy at a reduced feed-in tariff, you can add batteries to your solar panels. Surplus generation is used to charge batteries during the day, and you can use them at night. Just keep in mind you need a hybrid inverter, since standard inverters cannot handle solar panels and batteries at once. 

The main benefit of using batteries is saving the full value of each kilowatt-hour. In other words, solar electricity becomes more valuable:

  • In the previous example, we assumed that 2,000 kWh are exported to the grid at $0.10/kWh, and you save $200.
  • However, if that electricity is stored in a 95% efficient battery, you get 1,900 kWh during the billing period. If you’re normally charged 30 cents/kWh for that energy, you save $570.

Another advantage of batteries is being able to use them as a backup power source during blackouts. This is not possible with solar panels alone, since their production depends on sunlight. A solar system cannot deliver its maximum wattage on demand, but a charged battery can respond at full power in milliseconds.

The main limitation of battery systems is their initial price, but they are becoming more affordable. A solar power system with batteries is more expensive, but its power bill savings are also higher.

Conclusion

Solar panels can reduce power bills even if a home uses most of its electricity at night. Their electricity can be sold and deducted from your power bill, or stored in batteries and used later. 

  • Solar feed-in tariffs are recommended if you can get a favorable rate from your electricity provider, or if you want to reduce your installation costs. 
  • On the other hand, if you’re willing to invest in batteries, they can increase the savings achieved by solar panels. They can also act as backup power in an emergency.

Instyle Solar can analyse your electricity bills, to give you a detailed quote and savings estimate for both options – with and without batteries. That way, you can pick the option that meets your needs, based on a clear comparison of costs and benefits.

For more, visit our blog.

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