The growing environmental pressure resulting from the use of fossil fuels is leading mankind to make a transition from the use of traditional energy sources to that of renewable energy based clean energy. Because renewable energy has the feature of instability, it thus brings significant challenges on real-time power balance and power dispatching. Therefore, to secure the power supply, the grid needs to be upgraded by the selection of a reasonable grid structure and operation mode. In this paper, a multiple-level direct current (dc) loop grid, which would be the suitable mode for the future power grid, is suggested. Then, the high-temperature superconducting (HTS) dc power technology such as the HTS dc power cable and dc fault current limiter for the future power grid are discussed. We also report on the test and operation of a 360-m/10-kA HTS dc cable that is being built and would be used for an electrolytic aluminum plant of Zhongfu Group in Henan Province, China.