Home battery systems are emerging as a significant, and potentially more affordable, solution for both household energy savings and the broader fight against climate change. While solar panels often come to mind for domestic renewable energy, the International Energy Agency now identifies battery storage as the world's fastest-growing power technology. This includes home batteries, which can power a residence and even sell excess energy back to the national grid.
The UK has seen a notable surge in adoption, with more than 40,000 homes and small businesses installing battery systems last year, nearly doubling the previous year's record. This growth is partly driven by rising energy prices. For example, Octopus Energy reported a doubling of home solar and battery system installations between February and March following disruptions to energy supplies, with demand remaining elevated even after the energy regulator announced an increase in the price cap.
A key financial benefit for homeowners on variable tariffs is the ability to charge batteries during off-peak periods, when electricity can cost as little as 5 pence per kilowatt-hour (kWh). This stored energy can then power the home during peak demand hours, typically 4 pm to 7 pm, when prices can reach 40 pence per kWh, or even higher during periods of intense demand like heatwaves. While a professionally installed battery system in the UK currently averages around £9,400, the landscape is set to change with the introduction of cheaper, plug-in options. Octopus Energy, for instance, is developing a shoebox-sized plug-in battery, expected to cost less than £300, which could store 2 kWh – enough to run a fridge for up to two days. This innovation, anticipated for consumer approval in 2027, could significantly broaden access, potentially including renters.
Beyond individual financial gains, home batteries play a crucial role in reducing greenhouse gas emissions. By lowering consumption during peak times, they decrease the reliance on gas-fired power plants used to supplement lower-carbon energy sources. On days when Britain's grid operates almost entirely on zero-carbon sources, storing surplus energy in home batteries can be more beneficial for the climate than generating unneeded energy through home solar. Last year, for instance, the UK paid wind farms £379 million to cease operations when the grid could not accommodate the excess energy – a surplus that could have been partially stored in domestic batteries.
Looking ahead, as the proportion of solar and wind power in the national energy mix continues to grow, home batteries will become increasingly vital for grid balancing and further climate benefits. Iain Staffell at Imperial College London suggests that while solar may currently be more impactful, batteries are poised to become more critical within the next five years. However, the environmental benefits are not without caveats. Concerns have been raised by experts like Aritra Ghosh at the University of Exeter regarding the carbon footprint associated with battery manufacturing. Furthermore, there is currently no established infrastructure to recycle the millions of home batteries expected to reach the end of their lifespan, which Octopus anticipates to be at least 12 years.
Source: International Energy Agency, Imperial College London, Octopus Energy, University of Exeter