[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
dam-l Sea water irrigates crops, cools bldgs./LS
An interesting pilot in Hawaii.
Sea Water Irrigates Crops, Cools Buildings
KEAHOLE POINT, Hawaii, August 13, 1999 (ENS) - A
unique form of renewable energy is being used in
Hawaii to irrigate crops. Cold salt water from
the depths of the Pacific Ocean is being pumped into a field at the
Natural Energy Laboratory of Hawaii on the Big
Island to provide the plants with water.
The water never touches the soil or the plants
directly, but the cold pipes create condensation that waters the garden
and eliminates the need for conventional irrigation.
Chilling the roots also makes the plants perform
as they would in a perpetual spring, allowing artichokes, brussels
sprouts, roses and other non-tropical plant
varieties to bloom in the tropics.
The method is "a breakthrough for world
agriculture," says Dr. John Craven, president of Common Heritage
Corporation of Oahu which developed the
technique. "It allows us to convert the desert into a sustainable habitat,"
said Dr. Craven, holder of a degree in ocean
engineering.
Dr. John Craven (Photo
courtesy CHC)
The Common Heritage
Corporation (CHC) was established in 1990 by Dr.
Craven to develop
environmentally sustainable ocean resources. The for-profit
Hawaiian firm aims to
establish self-sufficient environmentally, economically
and culturally sustainable
communities in coastal zones and islands that have
access to deep ocean water.
Dr. Sylvia Earle, an internationally famous
oceanographer and explorer,
is a CHC board member.
The Natural Energy
Laboratory of Hawaii has a site on a lava desert near
Hawaii's Kona International
Airport, which pumps water from 2,000 feet deep to
improve the growth of plants
and shellfish. The experimental cold ocean water
garden is one of two dozen
enterprises at the state research agency.
The Natural Energy
Laboratory of Hawaii (NELH) was founded in 1974 by then
Hawaii Governor John Burns and Dr. Craven in his
capacity as Marine Affairs Coordinator of the State. Dr. Craven
continued as sponsor and chairman of the Board
until 1990, when the NELH as an independent State Corporation
was converted into an Authority under the
Department of Business and Economic Development.
Pipe carries cold sea water through strawberry
patch. (Photo courtesy Natural Energy Laboratory
of Hawaii)
The process of cold sea water condensation
irrigation creates
an environment in which nutrients are pumped up the
plants at a great rate. "The colder the root,
the tastier the
vegetables," says Dr. Craven. "When you harvest,
the plant
doesn't die; it just keeps growing."
Japan is preparing to launch a commercial
spinach-growing
operation on Okinawa's Kume Island, providing a
large-scale test of the process. That project is
expected to
pay for itself.
The Natural Energy Laboratory of Hawaii was
founded to
generate electricity from the temperature
differential between deep ocean water and the surface. After several costly
prototypes were built and tested, it appears
that at the current state of technology this method of generation is too
expensive for practical use.
Diver
examines pipes feeding
seawater from the ocean depths
to
the Natural Energy Lab (Photo
courtesy NELH)
But
the pipelines created for that project
by
Makai Ocean Engineering of
Waimanalo are now being used for the
deep
ocean water irrigation garden. The
NELH
currently pumps 16,000 gallons
of
water each minute, at 42 degrees F.
The
Hawaii Legislature has allocated $15
million to install a 55-inch pipeline that
will
pump from 3,000 feet down in the
ocean. It will triple the volume of water
for
research.
Other
uses for the cold ocean water are
being developed. Two of the biggest clam and
oyster producers in the U.S. use the NELH site to cultivate more
than 330 million shellfish larvae a year.
Air conditioning of buildings with cold seawater
is also being demonstrated at the Natural Energy Laboratory of
Hawaii. The Lab saves more than $4,000 a month
over previous costs in the cooling of its office and laboratory
building.
Analyses by Makai Ocean Engineering have
indicated that for Guam, 10,000 hotel rooms could be air conditioned
with cold seawater and that the capital payback
period for installing such a system would be approximately five to
six years.
Deep lake water, too, can be used to cool
buildings. Cornell University in New York is using a similar concept to
provide air conditioning for its campus. The
water is drawn from 270 feet beneath Cayuga Lake in a system also
designed by Makai Ocean Engineering.
© Environment News Service (ENS) 1999. All
Rights Reserved.
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
Lori Pottinger, Director, Southern Africa Program,
and Editor, World Rivers Review
International Rivers Network
1847 Berkeley Way, Berkeley, California 94703, USA
Tel. (510) 848 1155 Fax (510) 848 1008
http://www.irn.org
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::