Hampshire-based innovator Caldera is trialling their heat battery with support from Energy Systems Catapult as they aim to validate performance, gain consumer insights and accelerate the Net Zero technology market.

The patented Warmstone heat battery technology aims to replace traditional gas and oil boilers entirely and operates by storing electricity when it is cheaper or cleaner – to be used for on-demand heating and hot water through a conventional central heating system.

With extensive experience running trials in their real-world test environment – the Living Lab – Energy Systems Catapult is helping Caldera design and run a consumer trial in a number of homes to deliver independent validation of the innovation.

The Challenge

Two of the biggest Net Zero challenges facing the UK energy system are the variability of renewable energy generated by the wind and the sun, and the decarbonisation of home heating traditionally supplied by gas or oil boilers.

Caldera’s heat battery technology can store electricity at times of low demand (“off-peak”) or excess renewable supply, and turn the electricity into heat at times of low generation or high demand (“on-peak”). As a result, heat batteries can make a material contribution to creating a more flexible energy system that increases the use of renewable energy to decarbonise heat.

The Innovation

The Caldera Warmstone heat battery stores electricity as heat that can then be used in a conventional central heating system with radiators and a hot water tank at temperatures up to 80C.

The main product is sized at 100kWh which is enough to supply all of the heating requirements to a four bedroom house for 24 hours on the coldest day in winter. Alternatively, one or more units can provide hot water and heating for multiple apartments or a block of flats.

While “off-peak” is traditionally over-night, many low carbon technologies that provide flexibility will require electricity market reform – such as those proposed in the Catapult’s Rethinking Electricity Markets project. This means “off-peak” can take place at any time where there is excess renewable generation.  This will allow business models to be developed in the marketplace for consumers to buy both the lowest cost and cleanest energy available.

The Warmstone heat battery will store electricity, either via a signal from a utility or by the customer. In the case of utilities having control of the unit, there will be a potentially significant benefit to them when balancing generation and demand, as they will be able to turn on or off multiple units at short notice, representing huge flexibility to the grid without any noticeable impact on the customer.

The Energy Systems Catapult solution

With Caldera aiming to sell their Warmstone heat battery to home-owners – either outright as a product or with finance through a provider using a heat-as-a-service proposition – experts from Energy Systems Catapult’s Living Lab are helping Caldera to gain:

• Independent technical performance validation to determine the efficiency of the Caldera heat battery for individual homes and the overall system efficiency.
• Detailed consumer insight to understand the trial participants initial impression and installation experience, their experience of getting comfortable in their home through use of the heat battery, their heating/hot water use patterns and their motivations for taking part in the trial.

The trial follows on from previous work provided to Caldera by the Catapult’s Energy Launchpad accelerator, including: modelling insight to establish the size of the thermal storage market; market segmentation work to better understand the regulatory and incentive landscape; and refining the customer value proposition.

Guy Winstanley, Co-founder and COO, said: “We believe we’ve created the cheapest form of low carbon heating but we need that 3rd party performance verification of the product

“When you talk to people in the industry they ask you ‘what do the Catapult think’. Energy Systems Catapult is a good referee.”

Rebecca Sweeney, Living Lab business lead, said: “The UK needs to decarbonise heating in millions of homes in the coming decades, alongside other demands for renewable energy such as electric vehicles.

“Flexibility of demand across the energy system will be key to achieving Net Zero while keeping costs affordable, and storage technologies such as Caldera’s heat battery, will be vital.

“Our trial expertise, developed in the Living Lab helps innovators rapidly access real world consumers to market-test energy products and services, helping them accelerate through a phase of development that can otherwise be complex, time-consuming and expensive.

“Energy systems Catapult will provide Caldera with both qualitative and quantitative data to help validate performance and provide consumer insight.”