Sea Water Irrigates Crops, Cools Buildings

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Mark Graffis

Aug 14, 1999, 3:00:00 AM8/14/99
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

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.

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

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.

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.

© [20]Environment News Service (ENS) 1999. All Rights Reserved.


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