Wireless electric power transmission apparatus and electric power transfer system

An electric power transfer system comprising:

• a power receiver including
• a power reception antenna to receive electric power transferred by radio waves, and
• a beacon transmitter to transmit a beacon signal;
• and
• a wireless electric power transmission apparatus including
• a power transmission antenna to emit the radio waves toward the power receiver,
• a driver to cause the power transmission antenna to be directed to a direction in which the power receiver exists,
• a beacon receiver to detect the beacon signal transmitted by the power receiver, and
• a transmission signal generator to generate, when the beacon receiver detects the beacon signal, a transmission signal emitted as the radio waves from the power transmission antenna, wherein
• either one of the wireless electric power transmission apparatus and the power receiver is on sea and the other of the wireless electric power transmission apparatus and the power receiver is on land, and
• the emission of radio waves is stopped from the power transmission antenna in a case where the beacon signal is not detected, the case corresponding to a situation where either the power transmission antenna or the power reception antenna being on the sea is moved, motion of the power transmission antenna or the power reception antenna causes change in its orientation direction, and the power reception antenna cannot receive the radio waves emitted by the power transmission antenna.