For a future carbon-neutral society

it is a great challenge to coordinate between the demand and supply sides of a power grid with high penetration of renewable energy sources. In this paper

a general power distribution system of buildings

namely

PEDF (photovoltaics

energy storage

direct current

flexibility)

is proposed to provide an effective solution from the demand side. A PEDF system integrates distributed photovoltaics

energy storages (including traditional and virtual energy storage)

and a direct current distribution system into a building to provide flexible services for the external power grid. System topology and control strategies at the grid

building

and device levels are introduced and analyzed. We select representative work about key technologies of the PEDF system in recent years

analyze research focuses

and summarize their major challenges & future opportunities. Then

we introduce three real application cases of the PEDF system. On-site measurement results demonstrate its feasibility and advantages. With the rapid growth of renewable power production and electric vehicles

the PEDF system is a potential and promising approach for large-scale integration of renewable energy in a carbon-neutral future.