An apparatus for storing energy may include: a plurality of nanowire cells electrically connected to each other; and a storage for storing electrical energy generated from the nanowire cells. Each of the plurality of nanowire cells may include: first and second electrodes disposed at an interval; and a nanowire, which is disposed between the first and the second electrodes and made of a piezoelectric material. The plurality of nanowire cells may be electrically connected, so that voltage or current may be increased. Therefore, wireless recharging of the storage connected to the nanowire cells with electrical energy may be enabled.