Page 151 - Fundamentals of Ocean Renewable Energy Generating Electricity From The Sea

Chapter 6

Other Forms of Ocean Energy

Although the focus of this book is tidal, offshore wind, and wave energy, and
those topics have been covered in detail in the preceding three chapters, we
also recognize that there are other forms of ocean energy. These are primarily
ocean currents (specifically western boundary currents), ocean thermal energy
conversion (OTEC), and salinity gradient energy. These forms of ocean energy
are introduced and discussed in limited detail in this chapter, in which we
outline the main principles, technology types, commercial progress, potential
environmental impacts, and challenges.

6.1 INTRODUCTION
In addition to the forms of ocean energy that were discussed in detail in the
previous three chapters (tidal, offshore wind, and wave), there are three other
main types of ocean energy:
● Ocean currents
● Ocean thermal energy conversion (OTEC)
● Salinity gradients
Although these forms of ocean energy conversion are each limited to
particular environments (e.g. OTEC is limited to the tropics; see Section 6.3),
they all have significant potential for electricity generation.

6.2 OCEAN CURRENTS
Ocean current energy is the kinetic energy that resides in large-scale open-ocean
geostrophic surface currents. These currents transfer heat from tropical to polar
regions, influence weather and climate, distribute nutrients, and disperse marine
organisms [1]. Because these currents are largely driven by the winds, they
1
are actually indirect forms of solar energy. The Ocean Energy Council has
estimated that ocean currents have a globally extractable potential of 450 GW,

1. Because winds are driven by gradients in air pressure which are a result of variations in solar
energy received at the surface of the Earth.
Fundamentals of Ocean Renewable Energy. https://doi.org/10.1016/B978-0-12-810448-4.00006-9
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