What is ocean energy?

The surface area of ​​the Earth is approximately 5.1×10 8 km, of which the land surface area is 1.49×10 8 km, accounting for 29%; the ocean area is 3.61×10 8 km, accounting for 71%. In terms of sea level, the average elevation of all land is about 840m, while the average depth of the ocean is 380m, and the volume of the entire seawater is as high as 1.37×10 9 km 3 . The endless sea, not only provides people with shipping, aquatic products and rich mineral deposits, but also contains enormous energy. In general, ocean energy refers to renewable energy sources attached to seawater, including: tidal energy, wave energy, ocean temperature energy, ocean salt difference energy, and ocean current energy. More generally, ocean energy also includes wind energy over the ocean, and ocean surface. Solar energy and marine biomass energy etc. The global ocean energy has a large amount of renewable energy. The total theoretical renewable energy of these five kinds of ocean energy is 76.6 billion kilowatts. Although the intensity of ocean energy is lower than that of conventional energy sources, ocean energy still has considerable energy flux density among renewable energy sources.