Caldera has developed an innovative Heat Battery that stores renewable electricity at times of high generation to be used later at times of low generation for home heating and hot water.
Energy Systems Catapult via the Energy Launchpad is helping Caldera (formerly Pumped Heat) with modelling for market insight, a digital fitness assessment and preparations for test and demonstration.
The Innovation: Energy Storage
Caldera based in Fareham, Hampshire, has developed a Heat Battery using their Warmstone innovation – a low cost and safe technology that stores excess renewable electricity as it is generated to use later as heat on demand.
The energy is stored by using electric resistive heating to raise the temperature of a block of Warmstone. High quality insulation keeps losses to a minimum until the heat is required. On demand the unit is able to provide hot water and central heating at temperatures up to 70C, suitable for even the oldest home.
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.
Analysis by Caldera found their heat battery is a:
- Lower cost solution than either heat pumps or green hydrogen
- Accommodates properties requiring high temperature water with high power outputs
- Can be retrofitted to any property with an existing wet heating system as a straight boiler replacement
- Requires no other modifications to the property, such as fitting underfloor heating.
The charge cycle uses off-peak electricity, ideally from renewable sources. While off-peak is normally at night-time, it is expected that the market will transition so that off-peak can take place at any time there is excess renewable generation. This will allow strategies to be developed in the market place for consumers to be able to buy up the lowest cost energy available.
The unit is set to charge either by a signal from a utility or by the customer. In the case of utilities having control of the unit, there will be a significant benefit to them when balancing the generation to the demand as they will be able to turn off multiple units at short notice representing huge flexibility to the grid without any noticeable impact on the customer.
The Decarbonisation Challenge
Two of the biggest challenges facing the transformation of the energy system are the variability of renewable energy and the decarbonisation of heat – with around 75% of domestic energy used for space heating and hot water. So a technology that can store renewable electricity at a time of low demand and deliver it as heat at a time of low generation should make a material contribution to enabling the widespread use of renewable generation and reduce carbon emissions.
Caldera intend to sell their Warmstone heat battery to home owners – either outright as a product or finance it through a provider as a heat-as-a-service proposition. Their analysis found it would be a commercially viable solution in off-gas grid properties that have both the space to locate a heat battery and right electrical supply. There are 1,000,000 homes in the UK using heating oil and 200,000 homes using LPG/Cylinder gas.
The challenges that Caldera want to overcome are achieving 3rd party performance verification of the product: modelling insight to establish the size of the thermal storage market; further market segmentation work to better understand the regulatory and incentive landscape; and refining the customer value proposition.
Energy Systems Catapult is home to the Energy Launchpad, which provides carefully selected innovators with tailored business incubation and acceleration support to help address barriers to growth, de-risk innovation, scale-up the business and secure investment.
Tailored support for selected SMEs utilising the Catapult assets and capabilities, and delivery partner offerings, such as business model development, energy system integration assessment, consumer insights guidance, digital fitness, market testing and validation, investor readiness, specialist advice, as well as identification for Acceleration support.
Energy Systems Catapult and its partners will deliver:
- Modelling: Whole system modelling within the UK to establish that there is a place for thermal storage and the potential size of the market which will help when fundraising.
- Energy Market Insight: Further segmentation work to analyse the market in greater detail to establish the profile of properties in the UK, their rated electrical supplies (eg. 60, 80 or 100A supply), regulatory constraints and incentives to help to identify how the real market segment sizes correspond with the overall market identified by the modelling.
- Living Lab: Exploratory work to better understand the technology and Heat as a Service propositions in preparation for when the beta units are ready for test and demonstration. Potential houses where the units will be deployed should have baseline data to compare the new technology against.
- Digital Energy Fitness Assessment: Instrumentation and data analysis of the field trial unit will establish independent verification of data as well as guidance towards final market solutions for getting data out of homes to utility providers.
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