Launching in the wake of the Heat and Buildings Strategy, the HWA report comes with a stark warning for government to step up its efforts to decarbonise heating, or risk losing out on untapped energy storage around seven times the capacity of the UK’s largest pumped hydro power facility (Dinorwig in Wales).

Commenting, Isaac Occhipinti, director of external affairs, HWA said:“In order to meet Net Zero, all UK homes will need low to zero carbon heating. Most currently available low carbon heating solutions require a hot water cylinder.”

“There is much excitement around the role that energy storage technologies can play to help accommodate more low-to-zero carbon energy sources into the UK’s generation infrastructure, however, relatively little attention has been paid to hot water cylinders. There are currently approximately nine million hot water cylinders installed, in homes across England, which is less than 45% of homes in England, down from 77% in 2001. “

“However, this still equates to 70GWh of untapped energy storage (around seven times the capacity of the UK’s largest pumped hydro power facility, Dinorwig in Wales). HWA believes that homeowners with a hot water cylinder should be educated on its full potential and encouraged to retain it in order to future proof their heating system and maximise the UK’s energy storage potential.”

“Homeowners are not replacing or installing low carbon measures at the speed required to meet our decarbonisation targets. Also, where a hot water store has been removed the space is often repurposed for additional storage or bathrooms, and therefore re-introducing a hot water store can prove challenging.”

“In addition to meeting multi outlet demand, storage systems are essential partners to any renewable energy input as these sources need to be harvested and stored. Hot water storage is the only practical solution to turning the energy into something useful and banking it for when it needs to be used.”

“The energy storage potential associated with the UK’s installed capacity of domestic hot water cylinders is comparable to our entire fleet of pumped-hydro-electric storage and with just a fraction of this resource; it would be possible to absorb the largest surpluses of renewable power that arise from offshore wind and solar PV.”

“Government must do more to educate homeowners, local authorities and social landlords on the benefits and potential of hot water storage, and homeowners should be able to access incentives if they wish to replace their hot water cylinder with no stipulation on the type of system to be installed only that it is a suitable replacement.”

“If we do not invest in this untapped asset then it will become more expensive to upgrade homes to become ready for Net Zero. We also will not be able to take advantage of the current grid balancing potential of millions of hot water stores.”

‘No place like home’- the HWA’s full report on the potential of Hot Water Storage is available to download here.