How to use seawater temperature differences to produce electricity?

The ocean is the largest thermal reservoir for storing solar energy on Earth. Most of the thermal energy radiated from the sun to the earth's surface is absorbed by seawater. However, surface seawater absorbs sunlight and has a high temperature, while the Deep sea water does not see the sun and has a low temperature. There are thus temperature differences in the ocean, sometimes of the order of 20°C. This temperature difference can be used to convert thermal energy from the oceans into electrical energy for use. This method of generating electricity is called seawater temperature difference electricity generation.