Home energy storage has been around for a long time, but has mostly been used by those living in off-grid houses. Recently, new developments in technology and increases in domestic renewable energy has seen home batteries become far more popular with the general public.
If you are currently using renewable energy sources in your home, or planning to have them installed in the future, home energy storage can improve the efficiency of your system. It can thus reduce your energy bill and earn you money by selling electricity back to the grid.
Using PV (photo-voltaic) solar panels are a great way to lower your energy costs and reduce your carbon footprint.
However, one problem with solar panels is that a large portion of the energy produced by domestic solar panels ends up going to waste. Solar panels are only able to produce electricity during daylight, while most energy is used during the evening. Installing a solar battery in your home stores the excess energy produced during the day and discharges during the evening when demand is higher.
While this article will be focusing on storing your energy as electricity, it is important to remember that there are other options for energy storage. Thermal stores and heat batteries can both be used to store excess energy from solar panels or other renewable energy sources. These options are far cheaper than the electric alternatives, but the energy can then only be used for heating purposes.
Solar batteries do not come cheap. Solar storage batteries come in a range of storage sizes, typically between 3kWh and 14kWh, costing between £3,000 and £6,000. Solar batteries do not last forever and will need to be replaced periodically every 9 years.
If you do not already have a PV solar system, a typical 4kWp array of panels will set you back around £6,200.
Solar batteries and solar panels need to be coupled together through an inverter. These typically cost around £800 and will last around 12 years.
Considering these costs and lifespans, a full PV-battery set up will cost around £22,800 over a 25-year period. These prices will vary depending on your solar panels, the size of the battery you use and your energy requirements. For more accurate prices, it is important to contact a few different installers and compare prices.
Solar batteries are not for everyone, but in some cases they can significantly reduce your energy bills. Smaller solar PV systems are not likely to produce excess electricity above your daily use and are not likely to benefit from solar batteries.
It is possible for larger PV systems to produce a surplus of energy during the day but unable to reach a home’s energy requirements while the sun is down. Storing this surplus energy in a solar battery and discharging it during the evening allows you to be more dependent on your own solar power, and will go a long way to reducing your energy bills.
Before March 2019, it was possible to sell excess energy produced by renewable energy back to the grid through the Feed-in Tariff scheme (FITS). FITS have since been replaced by the Smart Export Guarantee (SEG), which requires all large energy firms to provide at least one energy export tariff.
If you are already registered to the FITS, installing a home energy battery can be very cost-effective, as you can use more of the electricity you produce without affecting your FITS payments.
Under the SEG, payments are made based on smart meter readings, so storing more of the energy you produce in a home energy battery will reduce your payments and be less cost-effective.
Every domestic renewable energy system is going to be slightly different. The best way to understand if a home energy battery will save you money is to ask an installer who will assess your energy production, home energy needs and the total installation costs to determine whether a battery will save you money on your energy bill.
For the next steps to getting a solar battery installed, check out the consumer guides from the Building Research Establishment (BRE)
In its current state, home energy storage does require a hefty investment and is only likely to save you money in very specific circumstances. However, the decision to use a home battery is not always financial, and many make the switch just to reduce their dependence on the national grid and lower their carbon footprint.
On the upside, home energy storage is still in its early days of development and is going to become significantly cheaper over the coming years, becoming a more financially viable option for more of the public.