Household activities underlying residential electricity demand: who does what during the evening peak?

Growing the proportion of electricity generated from renewable sources is an important goal. But periods of high energy demand are not always aligned with renewable supply, necessitating greater reliance on other sources such as fossil fuels. In Ireland, like many other countries, electricity demand typically peaks in the evening, driven largely by residential demand. Reducing or shifting household activities away from this evening peak period can thus increase the proportion of electricity generated from renewable sources. Understanding the flexibility potential of residential electricity demand requires knowing which household activities happen most during peak times, and what groups of people are most likely to perform them at those times, as well as understanding what might facilitate and motivate behaviour change. To investigate these questions, we use a behavioural science approach that is activity specific. Using a large dataset from an Irish tracking survey that adapts the day reconstruction method (Kahneman et al., 2004), we first record the time of day at which a range of activities – water heating and showering, laundry, dishwashing, and cooking, among others – take place. Focusing on the evening peak between 4 and 7 pm, we then investigate sociodemographic, household, and psychological variables associated with timing activities during this period rather than other times of day. We show that the factors associated with time of use (e.g., tariff structure, reported effort to avoid evening use, and household composition) vary by activity. We discuss the implications of our findings and note their value for demand side management mechanisms.