ETHNICITY

							                                    OCEAN ENERGY


Ocean energy is a vast renewable source. Among the many sources used to extract energy
from the ocean are waves, tides, currents, temperature differences & marine biomass.

Waves represent a potential energy, since one wave 1.8m high & 9.0m deep releases
approx. 10 kW of power in each meter of wave front. The major problem is its extreme
variability. Nevertheless, a steady source of this power exists in the trade wind regions
where waves have an average height of approx. 2.7m & a period of approx. 8 sec.

Tides have been used as an energy source in the U.S. since 1650 when a tidally powered
mill was constructed in Boston. In order to successfully harness the energy in tides, three
requirements must be met: 1) large tidal range, 2) suitable topography, & 3) timing of
power generation. Because few places meet these requirements, tidally powered plants
must be devised which provide the maximum mean high tide/low tide range for the longest
period.

Currents exist throughout the sea, but only at a few places is it feasible to tap them for
power &, even then, the energy density generally is low. Large extraction plants will,
therefore, be required. Some possible locations are: between East Africa & Madagascar
(Agulhas Current), between South America & the Caribbean (North Equatorial Current),
between Japan & South Korea (Tsushima Current), and between Indochina & Indonesia
(several Equatorial Currents).

Another potential energy source is the temperature differences between water masses,
allowing the extraction of stored heat & its conversion to electricity. This concept was first
conceived by d’Arsonval in 1881 & is currently known as Ocean Thermal Energy
Conversion (OTEC).

One major source of energy, which has been getting more attention but is still in the
experimental phase, is biomass from the ocean. Blue water ocean farms can be built to
grow & harvest kelp. The kelp can then be transformed into methane or other liquid fuels.
California kelp (Macrocystis pyrifera) is one of the fastest growing plants known, up to
one foot or more growth per day, and therefore its ability to convert sunlight into seaweed
tissue is better than most plants. Macrocystis is widespread in cool waters, occurring in
New Zealand, Argentina, Chile, Peru, and northwestern Baja California. If a commercially
viable system is devised, the implications for land-constrained (i.e. limited) countries is
certainly very promising.