The potential for domestic hot water tanks and hot-fill appliances to help balance power systems and reduce CO2 emissions

Saker, D., Coker, P., Vahdati, M. ORCID: https://orcid.org/0009-0009-8604-3004 and Carey, C. (2014) The potential for domestic hot water tanks and hot-fill appliances to help balance power systems and reduce CO2 emissions. In: 7th international conference EEDAL 13 energy efficiency in domestic appliances and lighting, Sep 2013, Portugal, pp. 1279-1929.

Abstract/Summary

The European Union is committed to having a 20% share of renewable energy in the overall energy mix by the year 2020. Due to the variable nature of renewable energy supplies, more balancing services will be required to maintain the stability of electricity supply systems. One area attracting considerable attention is the potential to engage domestic customers in providing demand response services. In particular this includes managing electric water heater and wet appliance loads, which together in the UK account for 20% of total domestic electricity consumption. This article demonstrates a method of time shifting domestic energy use without being disruptive to occupant’s usual lifestyles or comfort. A number of dwellings using electric water heating had meters installed to characterise the diversity of usage. Further analysis estimates that more dynamic electric heater switching can reduce standing heat losses from the hot water cylinder compared to how off peak switches are currently operated. Additionally, by replacing conventional cold-fill wet appliances with a new range of hot-fill appliances, resistive heating load is shifted away from the appliance to a hot water cylinder. The utilisation of hot-fill for washing machines and dishwashers was found to reduce electricity consumption on average by 64% and 34% in each appliance respectively. Findings from this study highlight that electricity and carbon savings can be realised in a significant proportion of UK households; both through the demand response of electric water heaters and by using hot-fill appliances. The relative importance of heat source and appliance usage is examined in order to inform how much electricity can be shifted or reduced in different domestic configurations. A Markov Chain occupancy based model has been developed to simulate the aggregated load curtailment potential from electric water heaters, as well as the thermal capacity of hot water tanks that enables load on response.