Estimating the residential population by building
The population distribution at the building level is used to estimate two features. On one hand, the electricity demand of the residential sector will be assessed using the local average electricity demand per capita. On the other hand, the estimated number of residents will be used to characterize the type of building ownership, based on the average family size.
To model the electricity demand at the building level, several methodologies can be used. Swan and Ugursal (2009), when reviewing modeling techniques for describing residential sector energy demand, distinguished two approaches: top-down and bottom-up. The top-down approach models the residential sector as an energy sink, and no concern is given to the individual end-uses. The bottom-up approach, on the other hand, extrapolates energy consumptions of representative individual houses to regional or national levels.
The methodology proposed is a function of data availability: 1) census population at the block group level, 2) building footprints in vector format, and 3) land use information.
The population estimation approach is based on dasymetric mapping with areal interpolation. Dasymetric mapping is a cartographic technique that allows limiting the distribution of a variable to the zones where it is present by using related ancillary information in the process of areal interpolationxe “areal interpolation” (Eicher & Brewer, 2001).
Here the goal is to disaggregate the total resident population from each census block group (source zones) to respective buildings with residential use (target zones), using ‘residential volume’ as the proxy variable. First, the Urban Atlas is used to characterize the use of each building in the Municipal map as ‘Residential’ or ‘Non-residential’. Then, the nDSM is used to impose an additional restrictive criterion: only buildings with at least one floor above ground (i.e., mean height ≥ 2.6 m) are deemed suitable for habitation and to receive resident population. Finally, this set of buildings receive a proportional (linear) share of the resident population of the respective block group based on the ratio of their volume to the total resident volume in the block group. Estimation of residents per building is rounded to integer values.