Page 30 - Fundamentals of Ocean Renewable Energy Generating Electricity From The Sea

Introduction Chapter | 1 21

TABLE 1.2 Estimated Levelized Cost of Electricity (LCOE) in the United States
Capital Fixed Variable
Plant Type CF a Cost O&M O&M b Transmission LCOE$/MWh
Conventional 85 60.4 4.2 29.4 1.2 95.1
coal
Natural gas 87 14.4 1.7 57.8 1.2 75.2
Advanced 90 70.1 11.8 12.2 1.1 95.2
nuclear
Geothermal 92 34.1 12.3 0.0 1.4 47.8
Biomass 83 47.1 14.5 37.6 1.2 100.5
Wind 36 57.7 12.8 0.0 3.1 73.6
Wind—offshore 38 168.6 22.5 0.0 5.8 196.9
Solar PV 25 109.8 11.4 0.0 4.1 125.3
Solar thermal 20 191.6 42.1 0.0 6.0 239.7
Hydroelectric 54 70.7 3.9 7.0 2.0 83.5
a
Capacity factor—see Section 1.5.
b This include the fuel cost which is zero for some technologies such as wind.
Source: U.S. Energy Information Administration, Annual Energy Outlook 2015, April 2015,
DOE/EIA-0383 (2015).

1.4.1 The Nature of Ocean Energy
Many oceanography textbooks include a diagram similar to Fig. 1.14, based on a
figure first sketched by Kinsman in 1965 [19]. This figure gives an indication of
how energy is distributed across various scales of waves that occur in the ocean,
including the wind waves that everyone will be familiar with, through long-
period waves such as seiches and tsunamis, to tidal waves. Tidal waves in this
sense are long-period waves that are governed by astronomical tide generating
forces (i.e. due to the Sun-Earth-Moon system). It may surprise some people
to hear of tides discussed as waves, but in fact wind waves and tidal waves
have many characteristics in common, particularly ‘shallow water’ wind waves
and tidal waves. More details on tidal waves and wind waves are provided in
Chapters 3 and 5, respectively. However, what is most evident from Fig. 1.14
is that wind waves and tidal waves contain the most energy across the ocean
wave spectrum; indeed, globally there is about 2 TW of each (see Chapters 3
and 5) and so, theoretically, there is an equal and globally significant potential
for generating electricity from both waves and tides. Tidal waves and wind
waves each contain potential and kinetic energy, and both energy forms are
exploited in ocean energy electricity generation. For example, surface point