Ocean covers almost three quarters (71%) of the surface of the Earth,and nearly half of the world's marine waters are over 3000 m deep. 海洋能是一种蕴藏在海洋中的可再生能源，包括潮汐能、波浪引起的机械能和热能，海洋通过各种物理过程接收、储存和散发能量，这些能量以潮汐、波浪、温度差、盐度梯度、海流等形式存在于海洋之中。 Ocean energy is a kind of renewable energy, which is reserved in the ocean, including tidal energy,wave induced mechanical and thermal energy, ocean through a variety of physical processes for receiving, storing and distributing energy, these energy in the form of tides, waves, temperature, salinity gradient, and ocean current exists in the ocean. The ocean energy can be derived from the solar radiation and the gravitational force between the celestial bodies.海洋能来源于太阳辐射能与天体间的万有引力 海洋能是一种清洁能源，其本身对环境污染很小 Ocean energy is a kind of clean energy, which has very little pollutionto the environment. 潮汐能 tidal energy,Because of the change of the gravity of the moon, the tide phenomenon, which causes the sea level to rise and fall periodically, so the sea water fluctuation and tidal flow . 潮汐发电，世界上最大的潮汐发电站是法国北部英吉利海峡上的朗斯河口电站，发电能力24万千瓦，已经工作了30多年。潮汐发电有许多优点。例如，潮水来去有规律，不受洪水或枯水的影响；以河口或海湾为天然水库，不会淹没大量土地；不污染环境；不消耗燃料等。 但潮汐电站也有工程艰巨、造价高、海水对水下设备有腐蚀作用等缺点。但综合经济比较结果，潮汐发电成本低于火电。 Tidal power is one of the ocean power, Rance estuary Hydropower Station is the world's largest tidal power station in the northern France on the EnglishChannel power generation capacity of 24 million kilowatts, has been working for more than 30 years. tidal power has many advantages. For example, tide is regular, is not affected by the flood and drought; in an estuary or bay is a natural reservoir without drown a lot of land; do not pollute the environment; the fuel consumption. However, tidal power station also has a difficult project, such as high cost, corrosion of the water on the underwater equipment, etc.. However, the comprehensive economic comparison results, the cost of tidal power generation is lower than that of thermal power. 上述不同形式的能量有的已被人类利用，有的已列入开发利用计划，但人们对海洋能的开发利用程度至今仍十分低。 Some of these different forms of energy have been used by humans, and some have been listed in the development and utilization of the plan, but the extent of the development and utilization of the ocean energy is still very low. 海洋能至今没被利用的原因主要有两方面：一，经济效益差，成本高。二，一些技术问题还没有过关。 There are two main reasons why the ocean can not be used until now. first，the economic benefit is poor and the cost is high. second, some technical problems have not yet passed. 本文来源：https://www.wddqw.com/doc/b0b96963680203d8cf2f244c.html