As the integration of renewable energy sources into the grid intensifies, the efficiency of Battery Energy Storage Systems (BESSs), particularly the energy efficiency of the ubiquitous lithium-ion batteries they employ, is becoming a pivotal factor for energy storage management.
On average, this works out at just under 5kWh per day. Mark has neither the financial nor practical means to install renewable technology. However, he can use a home storage battery to take advantage of cheaper off-peak electricity rates, perhaps with the likes of the Octopus Flux tariff. Due to its compact size, Mark opts for the Giv-Bat 2.6kWh.
If we take the typical 3,500kWh annual household electricity usage and divide equally across the year, it uses 9.6kWh per day. Assuming a battery has enough capacity to supply this and is ‘charged’ at a cheaper rate of 12p/kWh, the annual cost of electricity would be £420 (assuming there is no solar PV installed).
There are a number of electricity battery systems for homes currently on the market and more are likely to appear in the future. The capacity of home electricity batteries ranges from 1kWh to 8kWh, enough energy to boil your kettle from 10 to 70 times.
Without battery storage, a lot of the energy you generate will go to waste. That’s because wind and solar tend to have hour-to-hour variability; you can’t switch them on and off whenever you need them. By storing the energy you generate, you can discharge your battery as and when you need to. ‘But I don’t generate renewables.
Homes with a solar PV system and a divert device, which uses spare electricity from a renewable source to heat hot water, or with a phase-change material heat battery (see earlier), may usually see very limited financial benefits from also installing an electricity battery storage system.