Fundamentals of Renewable Energy Processes, 3rd Edition

Chapter 4

Ocean Thermal Energy Converters

4.1 Introduction

170,000 TW of sunlight fall on Earth. However, harvesting this energy is difficult because of its dilute and erratic nature. Large collecting areas and large storage capacities are needed, two requirements satisfied by the tropical oceans. Oceans cover 71% of Earth’s surface. In the tropics, they absorb sunlight and the top layers heat up to some 25 C. Warm surface waters from the equatorial belt flow poleward melting both the arctic and the antarctic ice. The resulting cold waters return to the equator at great depth completing a huge planetary thermosyphon.

Enormous power is involved. For example, the Gulf Stream,has a flow rate of of water, some 20 K warmer than the abyssal layers. A ...