Estimating residential electricity and CO2 intensity of time-use activity

Corresponding to the time-use lifestyle—time allocation on daily activities—examined in the previous chapter, this chapter is devoted to understanding residential electricity/CO₂ intensities of activities (Watt/hour/person or gram CO₂/hour/person). In performing a daily activity, electric appliances are utilized an consume electricity. However, no data are readily available on residential electricity intensities.

This chapter present a bottom-up approach to fill the data gap by reconstructing the electricity/CO₂ intensities of activities based on residential energy consumption survey and time-use survey on the appliance and sharing characteristics. One person’s daily residential electricity consumption (kWh/person/day, available in energy statistics) is understood as being incurred through conducting daily time-using activities (kWh/person/day for each activity, calculated through multiplying residential electricity intensity and time use).

Because the latter bottom-up data and the former energy statistics data are independent from each other, the equation will be used to validate the estimation of residential electricity intensities for making adjustment and revision when necessary. With data on China’s CO₂ emission factor of electricity, we will extend the research in understanding the CO₂ intensities of daily time-using activities.

We will then analyse the residential CO₂ intensities and especially compare them across different daily activities. The quantitative assessment will rank daily activities and put them into high, medium and low CO₂-intensive categories.

Due to data deficiency, we assume that the residential CO₂ intensities only differ between urban and rural residents, but not against other demographic indicators. Nevertheless, because this book primarily focuses on how time use affects residential CO₂ emissions, this assumption will not cause significant problems. Residential electricity intensities are decided by electric appliance ownership and users’ behaviors, which have little to do with time-use patterns. Essentially this assumption follows the method in energy consumption decomposition studies in which the impact of one variable is examined with other variables fixed.