Is battery storage right for me?

Battery storage allows you to store electricity generated by solar panels during the day for use later. It’s an exciting technology and  there are many things to consider before you invest in a system for your home.

Benefits of battery storage

Installing a battery storage system can provide a number of benefits when used in conjunction with an existing or new solar panel system.

A battery storage system can:

  • store excess solar energy so it can be used at night (depending on your feed-in tariff)
  • help further reduce your reliance on fossil fuel-based electricity from the grid
  • offset the increased cost of power used during peak times, such as during the evening
  • save money by storing energy from the grid overnight when prices are low to use during peak times when prices are high (depending on the agreement you have with your retailer)
  • provide electricity to your home during power outages (depending on your system).

Choosing the right BESS for you

Your system installer will help you understand Battery Energy Storage System (BESS) functionality and choose a system appropriate for your requirements. The decision will be based on your energy use and tariff, the size of your solar panel system, and what you are wanting from the system.

Here are some key factors to think about and discuss with your installer.

  • Calculate the cost of the battery system itself and the likely payback rates, as well as the potential energy savings, to get a complete picture of the total installed cost of the system.
  • Learn more about the technology. Do you know how much excess energy you generate from your solar panels each day? Are you comfortable using an app or portal to manage your BESS?
  • Do you have an appropriate space to install the battery? For example, manufacturer requirements might dictate the battery’s distance from the meter box, the size of the PV inverter or access to an internet connection.
  • Can the battery store and supply enough energy for your needs? This will depend on the nature of your household appliances, and your household energy usage patterns. Shift workers may have different needs from a family who all get home from work or school at the same time.
  • How do you expect to use your battery system? Is your aim to save money in the long term? To contribute to sustainability? Or have a back-up plan for blackouts?
  • Is the supplier a reputable company who can deliver on any potential warranty claims? Be sure they offer adequate after sales support and advice when you need it.

To get the most out of your solar and battery system, you may choose to reduce the amount of electricity you use in the evenings or overnight so you only use solar or solar-charged battery power. For example, you could run your washing machine or dishwasher during the day when your solar panels are generating power.

How much power you need from your BESS

When thinking about what you need from your battery energy storage system, there are two key concepts to understand:

  • power – how fast energy can be supplied (kilowatts, or kW)
  • energy – how much energy is stored by the system (kilowatt-hours, or kWh).

Some people like to think of this as the difference between your car’s speedometer and odometer. The speedo tells you your current speed (how much power you are using right now) [kW], while the odometer tells you how far you’ve gone (how much energy you’ve used in total) [kWh].

Your power requirements across the day will change depending what appliances you are using, when they’re switched on, and how long you run them for. Getting smarter about how your household uses power can lead to a reduction in your overall energy needs, which impacts your BESS requirements. Visit our Save Energy During Peak Times for tips and tricks.

Most battery systems currently on the market have a power rating around 5-12 kW. Multiple systems can be used to scale this up if necessary. A ‘typical’ house may use around 18 kWh of energy per day, although this can vary significantly.

Remember that as long as you stay connected to the grid, your battery storage system does not need to provide for all of your needs. The BESS and the grid can work in tandem to ensure you have all the power you need, when you need it.

Typical maximum power requirements of some high power appliances are:

AppliancePower requirements
Air-conditioner2 - 12 kW
Water heater3.6 kW
Clothes dryer2.4 kW
Electric kettle2.4 kW
Hair dryer1 - 2 kW
Dishwasher1.5 kW
Washing machine1.5 kW
Microwave oven1.5 kW
Plasma TV0.8 kW
LED TV0.2 kW
Lighting:
Incandescent
Dichroic
LED

100w
50w
6w

As a general rule of thumb, any appliance that cools or heats will need more power than other appliances.