Heat pumps or heat storage? Which is better

Part of decarbonisation initiatives involves removing gas heating from homes. Commonly heat pumps are proposed as a replacement due to their high efficiency. However, off-the-shelf heat pumps can only consume as they heat. Given the low thermal efficiency of many homes this means that heating demand is inflexible if health impacts of homes that are too cold are to be avoided.

Moving gas heating to electricity only saves emissions if electricity generation is also decarbonised. However, zero carbon generators such as wind or solar can only generate when it is windy or sunny. Therefore, to provide energy when it is not windy or sunny they must be complemented with energy storage.

Energy storage takes many forms. Batteries and pumped hydro are common examples of energy storage being considered today. Supplying heat pumps requires energy storage to be provided elsewhere to enable them to heat at all times. However, simple technologies such as heat banks combine storage and heating. These have existed for a long time and usually combine a simple resistive heating element with a dense material that can store heat, which then can be released later. Some of these devices are portable which also enables their use by people who rent. An example is here:

https://heatpac.com.au/Files/2022%20Allvalve%20Heatpac%20brochure%20LR.pdf

This project aims to model energy storage heaters, resistive non-storage heaters, and heat pumps to understand their relative cost, carbon, and comfort benefits in a high renewable energy system.