To provide a means for making power supply stable continuing to supply power for a long time as much as possible because power supply is not stable due to Fukushima Daiichi nuclear power plant accident or others.

Light (electromagnetic wave) of stars arrives at the earth across the cosmic space. Therefore, the cosmic space is filled with photons. A gravity wave also comes transmitting through the cosmic space therefore the gravity wave can be thought to be a kind of an electromagnetic wave. It can be understood that solar light (electromagnetic wave) has energy because it is warm when holding a hand to the sun. Accordingly, the gravity wave has energy. Therefore, heat can be taken out when forming holes in the ground.