The Ocean's Power
July 19, 2006 - Ken Silverstein, Editor-in-Chief - EnergyBiz
When Maine decided to enact an energy bill that would require
10 percent of its generation sources to come from renewable
energy by 2017, it knew the task would be challenging. To
get there, it will try and take advantage of one form of
green energy that gets little attention: ocean energy.
In fact, the Electric Power Research Institute, or EPRI,
has said that ocean power in Maine has the potential to
produce electricity that does not emit harmful pollutants
at a cost that is on par with wind and solar energy. And
ocean waves may be more reliable than other green energy
forms, largely because the tides are constant.
The potential is obvious: As the world's largest solar
collectors, the oceans generate thermal energy. Now the
job before scientists and engineers is to figure out how
to capture this energy and produce electricity. Sea water
is 832 times as dense as air, providing a six mile per hour
ocean current with more kinetic energy than a 217 mile per
hour wind, say experts. To bring the idea into the mainstream,
however, scientists and engineers must still show that their
work can be done on a large-scale basis.
"Ocean wave energy enables more straightforward and reliable
integration into the electric utility grid to provide reliable
power," says Annette von Jouanne, engineering professor
at Oregon State University, in a release that notes the
school is testing the viability of ocean power. "Wave energy
also offers much higher energy densities, enabling devices
to extract more power from a smaller volume at lower costs."
The World Energy Council says that ocean power could provide
as much as 10 percent of the world's electrical demand.
The catch: The technologies to allow that are not yet ready
for prime time. That said, the United States provides some
The shores off the California Coast and Washington State
could be sites for ocean power plants. Seattle-based Aqua
Energy wants to build a one megawatt facility near Washington
State that forces water through a buoy that spins a turbine
generator to create power. That so-called tidal fence uses
turnstiles that spin with tidal currents. Florida and other
areas of the Gulf of Mexico are also suitable for such development.
In the case of Maine, it has filed two preliminary permits
with the Federal Energy Regulatory Commission. Experts say
that ocean power could be generated for no more than 6.5
cents a kilowatt hour. While more expensive than coal resources,
the chief advantage would be the fact that such plants would
emit no greenhouse gas emissions.
"Harnessing the energy from Maine's big tides in an environmentally
friendly manner will reduce our dependence on imported fossil
fuels and will create jobs in the state," says Beth Nagusky,
director of Maine's Office of Energy Independence, in a
previously published news report.
Altogether, the U.S. Department of Energy says that there
are only a few hundred land-based sites in the tropics where
deep-ocean water is close enough to shore to make ocean
energy feasible. At the same time, it says ocean energy
does present environmental challenges. Tidal power plants
can impede sea life migration and can effect local ecosystems.
In Oregon, for example, they are studying the potential
affect on sea birds and marine life from electromagnetic
fields and undersea cables.
Newer technologies, however, are less problematic and don't
block migratory paths. The optimal solution is careful site
selection. That involves appropriate spacing of the plants
and choosing sites that preserve scenic shorelines.
To make ocean energy economics work, it will need to be
done on a large-scale basis. France's La Rance station is
the only industrial-sized tidal power station -- gates and
turbines are installed along dams -- in the world. The plant,
which went on line in 1966, produces 240 MW. The Annapolis
Royal Station in Nova Scotia, Canada, meanwhile, generates
about 20 MW of power using tidal power.
The United Kingdom could also be a potential spot for ocean
power. A proposed off-shore project near Lynmouth would
be capable of producing 300 kW of electricity and will become
a testing ground for other tidal turbines.
Indeed, the U.K. has announced it could host its first
large-scale ocean power project -- one that could be operational
within a few years. That announcement coincides with others.
South Korea, for example, is working on a large tidal and
wave power plant that would be able to generate 254 megawatts.
"The potential of (ocean power) is great," says Joseph
Huang, a senior scientist for the National Oceanic Atmospheric
Administration, in a news report filed by freelance writer
Carl Hoffman. "The oceans are the biggest solar collector
on Earth, and there's enough energy in them to supply a
thousand times the world's needs. If you want to depend
on nature, the oceans are the only energy source big enough
While the technologies to produce ocean energy exist, they
have a long way to go. But, the U.S. Energy Department does
have a program to assist developers and it is funding one
such ocean energy project 11 miles off the Florida coast
that would produce 120 kW. Meantime, Blue Energy of Canada
has developed six prototypes that produce up to 100 kilowatts.
The tidal fence, which acts like underwater windmills, allows
water and marine life to safely flow through.
It's clear that renewable energy will play a greater role
in bringing electric power to people all over the world.
Wind and solar energy are the most advanced forms of green
energy. But, ocean power has the greatest potential. The
key now is to get a few such facilities up and running to
demonstrate its viability.
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