Energy usage data comes from Dublin City Council (DCC). Data can be found here. The data represents the annual residential energy usage (Kwh) by DCC small area, collected during the CSOIreland Census 2016 (dataset created on 2016-05-11).
DCC small areas geometry data sourced from CSOIreland's PxStat API, made available through their R package, csodata. Information for csodata is available here.
The interactive Leaflet map can be downloaded by clicking this link.