Performance of a DC-based microgrid system in Okinawa

A DC-based microgrid system involving 19 faculty houses at the Okinawa Institute of Science and Technology was established in December 2014. The main purposes of this microgrid system are to exchange energy among houses using DC and to utilize surplus energy before rechargeable batteries reach capacity. During May 2015, 41% of energy consumption by residents was supplied by this microgrid system. In that month, 170 kWh were exchanged among houses. A simulation study suggests that this system could utilize 288 kWh of surplus energy per month during the Okinawa summer and that another 1000 kWh surplus energy would be wasted and could potentially be utilized.