NELHA was founded in 1974 to help develop ocean
energy when the Organization of Petroleum Exporting Countries
restricted oil production, and caused an American energy crisis.
NELHA was mandated to provide support facility for Ocean Thermal
Energy Conversion (OTEC) and related research.
OTEC is a developing technology at the NELHA site. Its location
was ideal for the production of ocean energy because it sits
on a point from which underwater land slopes sharply down under
the sea. OTEC takes advantage of the site by pumping warm surface
water and cold ocean water from depths of 3,000 feet.
OTEC use these temperature differences in three different ways
to produce energy. Open-cycle OTEC uses warm seawater as a working
fluid by boiling it at low pressure to produce steam. The steam
is then passed through a turbine that produces electricity. Cold
deep sea water is used to cool the steam at the end of the cycle
to condense the vapor back to liquid. If the hot water remains
separated from the cold seawater, it is desalinated water and
A closed-cycle OTEC uses warm seawater to heat a low-boiling-point
fluid such as ammonia. When the ammonia vaporizes it drives a
turbine to produce electricity. Cold sea water is used to condense
the vapor back to a liquid form, and it is recycled back through
A hybrid system uses both open- and closed-cycle technology to
produce electricity by using the steam technology as in an open
cycle, and also using ammonia as a working fluid as in a closed
cycle. The system recycles the liquids as in a closed cycle,
but also produces desalinated water as does the open system.
In 1979, the first closed-cycle OTEC called Mini-OTEC demonstration
produced 50 kilowatts of electricity. After eight months, the
operation shut down after the testing period.
This was the largest, most comprehensive project completed by
OTEC,” said Jan War a project manager at NELHA. There are
no running OTEC projects at this time, he said.
This was Hawaiian Electric Light Company’s first involvement
with ocean energy. The energy produced helped to provide air-conditioning
for buildings and moderate refrigeration, and is also used for
mariculture operations such as the production of algae, seaweed,
phytoplankton, and kelp. The facility also farmed lobsters, salmon,
oysters, giant clams, and abalone.
Asian bottled water companies take advantage of the deep sea
water by desalinating it and selling it for $6 per 1.5 liter
bottle in Japan.
According to War, a proposal from the Ocean Engineering and Energy
Systems International has been accepted for a 1 megawatt OTEC
power plant to be built in 2008. The energy produced by the plant
will be used to run the NELHA facility which uses between 5-6
megawatts to operate. War also said that they are also looking
into ways to produce hydrogen that could be used to fuel cars.
According to the Hawaiian Electric Web site, ocean-generated
electricity is not yet distributed to the public.
Solar Power Energy (SOPOGY), a Honolulu company, is also proposing
a project with NELHA to build a 30-megawatt facility at NELHA.
According to War, the company plans to first build a testing
site on one acre of land before the project is started.
For more information go to www.nrel.gov/otec/.