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The search for renewable energy has people looking everywhere—even
underwater. In the last five years, a new renewable energy industry
has emerged as tides and waves are tapped for their inexhaustible
power to supply communities along the world’s coastlines.
Ocean energy can be produced from waves, tidal currents and off-shore
wind farms. Wave energy devices use a range of technologies to produce
power from oscillation, such as hydraulic pumps or air pistons to
drive turbines, or linear induction motors. In-stream tidal and
river energy devices are dominated by a variety of turbine designs.
Off-shore wind utilizes large wind turbines on floating or seabed
installations.
Tidal currents are attractive to energy utilities because of their
predictability. Unlike using wind and solar power for energy, the
tides are always on schedule, and just two weeks of current data
at a site can predict the currents 24 hours a day for the next 30
years. Many good tidal power sites also have different channels,
so if one channel has a slow current, energy could be harnessed
from a channel with a stronger current as the tide changes, allowing
the energy to be leveled out over a region to provide steady, predictable
power.
Throughout the world, countries are exploring ocean energy. In 2001,
the International Energy Agency established the Implementing Agreement
on Ocean Energy Systems to provide a framework for collaboration
between countries. The Parliament in the United Kingdom has strongly
endorsed ocean energy and provided significant funding for pilot
projects. The Scottish Executive and other partners allotted £14.5
million to create the European Marine Energy Centre in the Orkney
Islands of northern Scotland to allow wave and tidal technology
developers to test and validate their systems. An Irish company
using U.S.-developed technology, Open Hydro Ltd., recently demonstrated
its tidal turbine at the centre, earning the company a $12 million
contract from Nova Scotia Power to demonstrate it in the Bay of
Fundy.
The U.S. is also actively involved in exploring these new sources
of energy. In 2004, the Electric Power Research Institute (EPRI)
initiated a nationwide survey of ocean energy resources that developed
standard models for wave and tidal technologies, economic analysis,
site evaluation and studies in dozens of locations. EPRI’s
work catalyzed new projects around the country. The Federal Energy
Regulatory Commission has received more than 50 applications concentrated
in the Pacific Northwest, where there are strong waves, tides and
wind, to develop commercial ocean energy projects.
The most advanced tidal project in the U.S. to date is the Verdant
Power Company’s efforts in the East River of New York City.
Verdant installed six windmill-type turbines for a demonstration
project, but the company hopes to build several hundred more units
to provide a significant source of power to New York City. Another
ambitious tidal project of eight tidal turbine “farms,”
with the potential to construct a thousand more, has been proposed
in the Puget Sound of Washington State.
Burton Hamner is the president of Puget Sound Tidal Power LLC
in Seattle. |
