By 2050, a staggering 70% of the world's population is projected to live and work in cities, and two-thirds of global primary energy consumption is attributed to cities, leading to 71% of global direct energy-related greenhouse gas emissions. Smart cities will consist of sustainable infrastructures with buildings as major constituents. Buildings' energy consumption contributes to more than 70% of electricity usages, with people spending more than 90% of their time in buildings nowadays.
