1.3 Trends over time

Rationale: Future demand depends on the energy intensity of end use practices and how they change. Having established methods of representing and analysing the distribution (1.1) and timing (1.2) of end uses the next step is to determine which are changing, at what rate and with what implications for CO2 emissions.

Method: This requires use of historical data sets (Anderson), tracking changing practices, e.g. occupancy patterns, appliance use, and household routines over time (Torriti), and using pseudo panels and longitudinal data to show how participation in selected end use practices changes over the life course, and to distinguish between age and cohort effects (Anable). Data sources to be used include the 1997-2001 HomeOnline longitudinal timeuse survey, the UK 2005 and 2001 Time Use surveys and historical components of the Multinational Time-Use Study; British Household Panel Survey/Understanding Society Survey (since 1991).