With the gaining of popularity of concept of distribution generation (DG) and sustainable development, DG with renewable energy (RE) sources is one of the possible ways for building energy supply in the future. The current "DC-AC-DC" route from DG to DC loads via inverters may not be rational from the viewpoint of system simplicity and energy efficiency, a review on the current electrical distribution systems should be made. This paper reviews and evaluates possibilities of using DC electrical distribution systems with increasing RE resources and DC loads. There is potential of increasing energy efficiency and power quality. Drawbacks and merits are also identified.