A storage device includes a solid state drive (SSD), a field programmable gate array (FPGA), a power sensor and a global controller. The SSD stores data and receives power through a power rail connected to a host device. The FPGA processes data read from the SSD or data to be stored in the SSD and receives power through the power rail. The power sensor is connected to the power rail and generates a measured power value corresponding to a total power consumed by the SSD and the FPGA by measuring the total power. The global controller determines one of the SSD and the FPGA as a priority component operating with a fixed performance and determines the other of the SSD and the FPGA as a non-priority component operating with a variable performance in a priority mode based on power control information provided from the host device.