In Japan, the experiment, which generates power from solar panels put on the sea and in the sea, started in metropolitan area. That's because places, where can put solar panels on the land, have been decreasing recently. The experiment might be chances to pave new way of spreading renewable energy for Japan with its small land. Sumitomo Mitsui Construction Co. conducted a verification test at the place where used to be for a canoe competition in Tokyo Olympic Game. Solar panels are floating across 30 meter square on the sea. The cost for types put on sea is 20% higher than ones on lands, but cooling them by water can enhance power generation efficiency when the panels generates power in the sea because they have weakness for heat. On the other hand, solar power on the sea has some issues. One of them is salt damage. So, they are going to check if there is erosion on the devices. The panels also can be broken by the change of wave and a tide level. Solar power in the sea also can prevent the panels from getting dirty by bird's excrements and yellow sands. However, they turned out the biggest enemy is barnacles. They stuck to the panels and that causes to reduce generation efficiency. We will find solutions for these issues in the future and I believe they will be very useful for Japan with small land.