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Welcome to the family, Kumejima


The County of Hawaii has entered into a Sister City Relationship with the island of Kumejima, Okinawa, Japan. The relationship was formalized Sunday during a Ocean Thermal Energy Workshop (OTEC) at the Natural Energy Laboratory of Hawaii.

The mayor of Kumejima, Choukou Taira, and Mayor Billy Kenoi stressed economic ties rather than the traditional cultural bonds of sister city relationships.

Kumejima is an island about 50 miles east of Naha, Okinawa. Much like Hawaii Island of about 20 years ago, Kumejima’s economy is based on the visitor industry and sugar cane, known as sato kibi in Japan.

Kumejima, which has a climate and appearance similar to Kauai, also shares another similarity with HawaiiIsland, a deep sea pipeline which has allowed aquaculture to blossom on the island, which is about the same size as Molokai.

In November, public and private officials visited Kumejima to take part in an OTEC Workshop, where the possibility of a partnership between Kumejima and Hawaii Island was discussed.

This pact, which could result in the establishment of a demonstration plant at NELHA using the 55-inch pipelines already installed at the facility on Keahole Point, will be further discussed at the workshop by Japanese and American officials.

It was during this visit in November that the governments of Kumejima and Hawaii County realized that a sister city relationship would be a natural extension of the proposed natural energy partnership taking place at the time.

“We are honored to enter into this agreement with Kumejima,” Kenoi said. “The similarities between our islands are striking, including the fact that we are both outlying islands of island groups far away from their mainland countries. I think we can learn many things from each other as we both strive to break our dependence on fossil fuels.”

OTEC technology, which was successfully tested off Keahole Point in the 1970s, uses the temperature difference of deep sea and surface water to make a working fluid — in this case ammonia — to “boil.” The boiling fluid releases “steam” which is used to drive a turbine.

Intensive OTEC research is now taking place in a number of places in the world, including NELHA, where Lockheed-Martin recently blessed a facility, and at Saga University in Saga, Japan, where scientists are generating electricity using a small demonstration unit.

“OTEC has the potential to provide virtually inexhaustible, clean energy in the equatorial regions of the earth,” Kenoi said. “This is an opportunity for Hawaii Island to play a role in furthering a technology that could have worldwide implications.”


Okinawa-Hawaii OTEC experts gather at NELHA

U.S. and Okinawan technical, environmental and financial specialists in ocean thermal energy conversion (OTEC) swapped knowledge during a two-day Ocean Energy Workshop at the Natural Energy Laboratory of Hawaii (NELHA) facility.

The goal of the workshop, which ended Monday, Sept. 12, was to move OTEC further toward commercialization. Okinawa and Hawaii share a common problem—over reliance on fossil fuels—but also share a common asset in access to big temperature differences between surface and deep ocean waters.

OTEC, which was tested here in the late 1970s and found feasible by the U.S. government, uses these temperature differences to generate electricity. It is an expensive system to build, but can produce power for a band of subtropical and tropical areas around the globe. Cheap oil prevented alternatives such as OTEC from reaching commercialization.

“Our workshop sought to advance effective OTEC systems that can be demonstrated in both Hawaii and Okinawa by sharing technical, environmental and financial challenges,” said Guy Toyama of Friends of NELHA, which organized the workshop. “The Hawaii-Okinawa Task Force was formed as part of the U.S.-Japan Clean Energy Action Plan in 2009, and we’ve been working together since then.”

Okinawa, like Hawaii, is a long way from its nation’s mainland and Kumejima Island is at the most distant point. Both already use deep water pipes to support industry, such as aquaculture and water desalination.

“The next steps are farming and energy,” said Kumejima Mayor Choukou Taira. In a ceremony surrounded by Hawaiian culture, Taira and Mayor Billy Kenoi inked a sister city agreement during the workshop.

The technical specialists debated whether a demonstration or pilot plant should be built, or if incremental research and development steps would be more politically and technically feasible. The workshop participants debated that if a pilot plant were built, should it be the proposed 1megawatt size or something smaller. Commercial plants are expected to be at least 25 megawatts, with plans on the drawing board for 100 MW and located offshore.

Saga University in Japan is conducting extensive OTEC research and seeks to work with Hawaii to develop next stage facilities in Kumejima and NELHA.
Breakout sessions outlined the following challenges and considerations.

Environmental aspects that need to be considered for onshore, the team decided: Interruption or change of habitats, cultural issues, visual issues, assessment of deep-water nutrient impact, thermal issues and entrainment of organisms in the uptake pipe. Offshore issues—cable impacts, acoustic, visual and navigational impacts.

Technical considerations: No technical barriers to a 1 MW plant, but there are political ones including protecting downstream tenants from contamination.

Financial considerations for a 1 MW plant could include seeking support from the U.S. Department of Defense, a bilateral project with Japan/U.S.; or organizations like Blue Revolution Hawaii becoming a fundraiser.

Policy considerations: Need for healthy competition in the OTEC field; testing as large a scale as possible at NELHA should be entertained.

Workshops between the two countries will continue as part of the Task Force.

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