Home Energy Storage - your questions answered

Here are some questions that we get regularly asked. If you need further information, please call us or submit the question form below.
The three big wins of storing electricity at home?
  1. If you have solar panels, you can store your day-time generated electricity for later re-use, and still get your FIT tariff paid.
  2. In the day electricity is more expensive, so by storing cheaper night energy then you can save money.
  3. If you suffer occasional power cuts, battery storage can allow you to run essential services such as your freezer or your router.
Do I need solar panels to benefit from Home Energy Storage?

Not always, but the savings are best when you have solar panels installed.

However, our strategy takes advantage of both solar and the Economy 7* cheap overnight tariff. For a battery only case, the savings depend on your use pattern, but standard models show a return on your investment of around 4% per year at current energy prices.

Of course, if you already have solar panels, then your savings will be even higher.

*We show economy 7 running 11pm to 6am, but this varies slightly by supplier and by region

I already have solar PV. What will happen to my FIT export payments?

This is a win-win for you.

Our systems are fitted after the generation meter, so your FIT readings are unaffected. Under current legislation you will also still get your export tariff payments, even if you keep the energy yourself in a storage battery for use when it is needed.

How long will it take to get a system installed?

Not long. Typically within 2 weeks of receiving your deposit, but we will always make sure it is at a time to suit you.

This doesn’t affect any of your normal consumer protections, including the 14 day cooling off period.

What is home energy storage?

This is primarily battery storage that stores electricity when it is cheap or plentiful, and makes it available to you when it is most needed.

How is energy storage measured?

Batteries store energy measured as kWh (this is exactly the same as the ‘unit’ of electricity in your electricity bill). To imagine what it means, consider a typical electric fan heater rated at 1 kW. If you have a 5 kWh battery, it could run that heater for 5 hours at 1 kW.

What is useable capacity?

To avoid damage to your battery, it is never drained completely. Our systems allow the drain level to be set to ensure your battery life is maximised. The useable capacity is how much of your total battery capacity is available to use when the battery is fully charged.

What are battery cycles?

Batteries are usually warranted for a certain number of cycles over their lifetime. A ‘cycle’ means a full discharge / recharge cycle. If you only partially drain the battery before recharging it this would count as a partial cycle. The number of cycles multiplied by the useable capacity gives the total energy that will be available to you over the life of the battery and that is warranted by the manufacturer. Of course good quality batteries are likely to keep working well beyond their warranty.

How does the power output differ from the energy stored?

A good analogy is water. Imagine a bath full of water. The water is like a volume of stored energy (the kWh). Now imagine a tap that is open and the water starts to flow out. The amount that flows out each second is like the power (kW). The water (energy) will pour out of a big tap, but only trickle out of a tiny hole. The power needs to be sufficient to run real world equipment (a big enough 'tap'). For example, a kettle typically uses 2 kW for a few minutes. If your battery can deliver a power output at 2kW or above then it will all come from your cheap stored energy.

Will it help with power cuts?

This is your choice - as an optional extra we can help design an emergency power system (EPS) to help you cope with power cuts. There are two main options:

  • A single socket on the storage system to allow you to plug in whatever is most useful such as to keep your smart phones and LED torches charged. Keep your router plugged in so you keep internet connectivity.
  • A specific ring main could be kept powered. This could protect your fridge and freezer, or allow you to use your gas cooker and central heating, and power some lights. This option would require some additional wiring work.

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