Conservation Update: Natural Energy Laboratory of Hawaii Authority Returns to Its Energy Roots
This article was featured in the January-February 2008 edition of the State Energy Program's bimonthly newsletter, Conservation Update.
by Jennifer Josey, National Renewable Energy Laboratory
Warm surface temperatures predominate in tropical climates from 0 to 23.5 degrees north and south latitudes. Cold, deep-sea currents follow the contours of the Earth's surface beneath the oceans and directly around Hawaii.
Credit: Natural Energy Laboratory of Hawaii Authority
What began as a breakthrough in a small-scale ocean thermal energy experiment 34 years ago has matured into a full-fledged commercial epicenter. In response to the oil embargo in 1974, the Hawaii Legislature established the Natural Energy Laboratory of Hawaii Authority (NELHA) on the Big Island of Hawaii to investigate alternatives.
As a state agency, NELHA combines research facilities and a technology park, as well as enterprise and free-trade zones. The complex now stretches from the seashore to the Queen Kaahumanu Highway, occupying 870 acres bordering the Kona International Airport.
NELHA has established the technical baseline for ocean thermal energy and a multiplicity of uses for cold, pure, deep seawater. And it has become a prestigious center for ocean research and world trade in aquaculture products.
But the high energy prices that afflict Hawaii—the highest in the United States—have returned, and the state now depends on petroleum more than ever. Analysts at the Hawaii Energy Office, which manages NELHA, estimate that per year, the State of Hawaii spent $4-7 billion, with the Big Island spending $750 million, to pay for oil imports.
However, the Big Island—blessed with renewable resources like geothermal, solar, ocean, hydro, and strong wind—provides abundant and diversified renewable energy potential. As a result, Hawaii business and political leaders, including Governor Linda Lingle, are once again examining the extensive renewable energy resources of the Big Island of Hawaii.
The Siren Call of Ocean Thermal Energy Conversion
Where ocean thermal energy is concerned, no place is more capable than Hawaii.
The volcanic eruptions that have been creating the Hawaii Island chain for 7 million years still continue to create new lands below sea level. The most remote island chain in the world, the Big Island, is essentially a mountain that starts 20,000 feet below the surface. As a result, pristine, deep-sea currents pass near the shore. These submarine flows perpetually transverse the globe at a snail's pace, unaffected by pollution, bacteria, or pathogens on the surface (see map).
The Big Island, relatively young in geological terms at only 800,000 years old, has a bathymetry (underwater topology) that is very steep, making access to deep sea water available a short distance from shore. At Keahole point, a distance of 8,000 feet offshore takes you to a depth of 3,000 feet, allowing access to deep ocean water with less expensive piping.
Even though deep-sea currents are frigid, the Hawaiian archipelago has a tropical climate with consistently warm year-round surface temperatures. This consistent temperature difference of 40°F enables electricity generation from ocean thermal energy conversion (OTEC).
Warm surface temperatures and cold deep-sea temperatures are available across a wide area of the Earth's equatorial oceans (see maps). Thus, OTEC taps an inexhaustible source of renewable energy. The only byproduct is reservoirs of clean, fresh water.
The possibility of producing electricity from OTEC has intrigued scientists for more than a century. French scientist Jacques d'Arsonval first proposed the concept of OTEC in 1881. Unfortunately, his experiments were not successful. Fifty years later, the first attempt to produce electricity from OTEC in Matanzas Bay, Cuba, consumed more energy than it produced.
The NELHA Mini-OTEC Barge produced the first net electricity from ocean thermal energy. These early experiments established the technical foundation for most of what the world knows about OTEC today.
Credit: NELHA
Experiments Produce Net Electricity
In 1979, scientists at NELHA (originally known as the Natural Energy Laboratory of Hawaii) successfully produced electricity from OTEC for the first time. The NELHA scientists used a closed-cycle system that takes advantage of a conventional Rankine thermodynamic cycle. This is the same cycle that is used on conventional power plants, but OTEC operates at a much lower temperature differences (40°F at Keahole Point, Kona). The NELHA Mini-Barge produced 10–15kilowatts (kW) of net electrical power.
These first successful OTEC experiments at NELHA established the practicability of the technology and outlined its challenges. For example, the cold-water pipes must be large enough to handle high volumes of cold water, making the interface with a small barge problematic.
By the same token, a sea-land interface is vulnerable to wave action near the shore and to catastrophic events such as hurricanes, tsunamis, and earthquakes. For example, an earthquake in October 2006 destroyed the interface between the sea- and land-side sections of a cold-water pipe that supplies NELHA tenants; it is still under repair.
The requirements of the OTEC energy conversion cycle dictate that temperatures and pressure conditions be closely controlled. This is because surface seawater on the warm side of the thermodynamic cycle is turned into steam by lowering pressures to almost a full vacuum, resulting in a low pressure difference across the turbine. OTEC equipment must therefore meet very high control and reliability requirements while it moves large volumes of seawater.
Closed-cycle OTEC uses the Rankine thermodynamic cycle to generate electricity, which is the same cycle used on conventional power plants.
Credit: NELHA
NELHA scientists have also experimented with open-cycle systems to document performance. Open-cycle OTEC is attractive because the condensed vapor collected is pure, fresh water, which is an extremely valuable commodity in Kona and on most tropical islands (in closed-cycle OTEC, the condensate is recycled and reused). A 1 MW open-cycle system, like the one planned to be built at NELHA, can produce 600,000 gallons of fresh water per day. However, open-cycle OTEC still faces materials and design challenges, and the technology is still classified as "under development" by the World Bank.
Costs remain a challenge for OTEC. Seventy-five percent of the cost is for installing the cold-water pipe. This pipe must reach an ocean depth where there is a surface temperature differential of 40˚ F. The costs of such an installation are high enough that they cannot be recovered with energy payments at today's prices. This leads to the pursuit of multiple uses for the cold seawater.
In 1981, NELHA scientists moved their OTEC testing equipment from the barge to dry land. Then, as oil prices began to decline during the 1980s, so did interest in OTEC experiments. By 1984, NELHA began to use the class AA seawater to aggressively pursue other economic paths.
Champions of Economic Development on the Big Island
Even though ocean energy experiments diminished during the 1980s, NELHA found a new use for cold deep seawater in aquaculture and commerce. This niche would prove invaluable to local authorities, who are continually looking for economic development opportunities that reduce the Big Island's dependence on tourism.
Multiple pipes provide water from various depths, allowing tenants to control the temperature and flow of seawater. Long blue lines indicate the deep seawater pipes and short red lines represent the surface seawater pipes.
Credit: Friends of NELHA
Channeling the Future
First, NELHA had to build the infrastructure for supplying commercial tenants with thousands of gallons of seawater 24 hours per day, 365 days per year.
Between 1980 and 1985, NELHA constructed the necessary pipes for pumping deep seawater from 2000 feet and surface seawater from 45 feet. The first of the pipes, the 12-inch deep seawater pipe, was the first to use floating materials anchored at a depth of 2000 feet. The pipes are bored through the lava rock that makes up the shores of Kona. This also allows the connection between the sea- and land-side sections of the pipe to take place underwater and not be exposed to waves and weather.
By 2005, a 55-inch deep seawater pipe was installed to pull water from a depth of 3000 feet. This pipe runs almost two miles offshore and passes over a huge underwater cliff before diving into a deep channel. The pipe is attached to the cliff with a buoyant catenary design that attaches to the undersea rock with pendant weights. This structure allows pipe movement and maintains the integrity of the underwater structure.
Onshore, a lengthy pipe infrastructure snakes over and underground throughout the complex to tenants who pay for the seawater on a per-gallon basis. These tenants are attracted to the benefits of nutrient rich, pathogen, and pollutant-free deep seawater in a controlled environment onshore.
Algae growers at NELHA take advantage of the high concentration of nutrients in deep seawater.
Credit: NELHA
Creating Business Opportunities
These tenants now include companies that grow specialty fish for export to aquariums worldwide, bottled water (popular in Japan), spirulina for North American health food stores, and fresh fish for local restaurants and markets across the Pacific.
NELHA researchers have developed breakthrough methods for breeding popular high-value species to reduce pressures on wild stock. These include species that are popular with epicures such as prawns and clams, which grow more quickly and to a larger size in cold water. But it also includes species such as abalone and halibut that inhabit deeper waters.
Companies geared toward sustainable industry development also saw the potential that NELHA had to offer. One such company, Indo-Pacific Sea Farms, Inc., is developing technologies for sustainable commercial production of reef-dwelling organisms, including giant photosynthetic clams and reef-building corals. In total, almost 30 diverse commercial and pre-commercial companies recognized NELHA's diverse potential and made the move to Keahole Point.
Tropical fish grown at NELHA have become a specialty export from the Big Island of Hawaii to aquariums around the world.
Credit: NELHA
Partial List of NELHA Tenants
NELHA's current tenant list, upward of 25 enterprises, generates $30 to $40 million for the Hawaiian economy annually.
Commercial tenants include:
- Big Island Abalone Corporation – Created the PolyGrow® culture system
- Black Pearls, Inc. – Developed specialized hatchery technologies for black-lip pearl oysters
- Cyanotech Corporation – Produces high-value microalgae-based pharmaceuticals
- Koyo USA Corp. – Bottles Hawaii Deep Seawater
Pre-commercial tenants include:
- Moana Technologies, Inc. – Perfecting shrimp farming productivity
- Pacific Planktonics – Developing methods to culture marine fish and shrimp for scale-up to commercial production
Research tenants include:
- The Oceanic Institute – Developing new aquaculture industries and markets
- University of Hawaii – Monitoring atmospheric infrasound signals
- University of California – Sampling dissolved organic nitrogen compounds from surface and deep seawater
Hawaii's initial promotion of economic development has not diminished in the last decade; in fact, the drive for external collaboration has swelled. Among the newcomers to the NELHA campus is the Hawaii Natural Energy Institute, which has discussed plans for onsite hydrogen production and storage. Sopogy, a solar thermal developer, has also leased space that will be dedicated to 7 acres of its 1 MW solar thermal collector system. Cellana, a joint company formed by Shell and Hawaii-based HR Biopetroleum, will also be located at NELHA. Cellana will grow high-lipid algae strains that are native to Hawaii or approved by the Hawaii Department of Agriculture marine algae to produce vegetable oil for conversion into biofuels.
Additional Support from the State and DOE
In 1998, the Hawaii Energy Office published the Hawaii Climate Change Action Plan, which stated that the OTEC experiments needed, "additional research, component cost reduction, and funding of a utility-scale plant to create a viable commercial technology." To facilitate these needs, the Hawaii Legislature passed new legislation allowing NELHA to expand and bring in new organizations to help supplement the cost of its experiments and expansions.
The influx of renewable energy developers to the NELHA site is being bolstered by the U.S. Department of Energy (DOE). In January 2008, Hawaii and DOE announced creation of the Hawaii Clean Energy Initiative, which lays the groundwork for Hawaii to be energy independent. The initiative is founded on the idea that Hawaii must combine its abundant natural sources with the latest renewable energy advancements to accelerate its clean energy future. In so doing, Hawaii could become a model for the world, demonstrating what can be accomplished by developing renewable energy.
In her 2008 State-of-the-State Address on January 22, 2008, Hawaii Governor Linda Lingle stated that her administration is devoted to, "a direction that encourages personal responsibility, transforms the economy, focuses on energy independence, preserves our cultural and natural resources, and enhances our overall quality of life." You can read the address online.
NELHA Timeline
- 1974: NELHA established
- 1979: 12-inch surface seawater for OTEC heat exchanger materials testing
- 1981: 12-inch deep seawater pipe installed at 2000 feet
- 1983: Aquaculture research starts
- 1983: Deep seawater used for air-conditioning research
- 1987: Hawaii Ocean & Science Technology Park
- 18-inch deep seawater pipe installed at 2000-foot depth for OTEC
- 40-inch deep seawater pipe installed at 2000-foot depth for OTEC
- 28-inch surface seawater pipe installed for OTEC
- 1989: NELHA laboratory uses deep seawater for air-conditioning
- 1992: OTEC research unit established
- 1993: Tunnels dug for 55-inch pipes
- 2000: Surface water booster pumps begin operation
- 2005: 55-inch deep seawater system begins operation
Gateway Center Reaps National Honors
NELHA has been nationally recognized with many awards for the Hawaii Gateway Energy Center, two distinctive buildings that comprise the NELHA office and a visitor center.
Completed in 2004, the Gateway was designed by Ferraro Choi And Associates, a Honolulu-based architectural firm, for distributed and renewable energy research and development.
The award-winning Gateway Center houses a visitor center and business incubator.
Credit: David Franzen
National Awards
Most notably, by 2005 the Gateway was the eighth building to be honored with the U.S. Green Buildings Council's highest award—the LEED Platinum designation. This accomplishment is particularly impressive because, although the building was constructed with a $4 million federal grant from DOE, it shares the same class with $100 million structures.
More recently, the AIA deemed the Gateway a COTE winner, making it one of the Top 10 Sustainable Architectural Projects for 2007. This award distinguishes projects that demonstrate the highest accomplishment in environmentally sustainable architecture, combining inspired design, systems analysis, and performance. The facility's use of active and passive technologies such as daylighting, a passive conditioning system, and a copper roof for heat absorption made a profound impact on the AIA award jury.
"The architecture displays obvious concern for the environment and becomes a symbol — a teaching tool for sustainability."
–Honolulu AIA Jury member.
Also in 2005, the Honolulu Chapter of the Architects Institute in America (AIA) awarded the Gateway with the 2005 Sustainable Design Award. This award, meant to emphasize that beautiful work is sustainable work, is an honor based on well-articulated aesthetic achievements, integrated strategy, and energy efficiency.
In 2006, the Honolulu AIA bestowed the Gateway with the Northwest and Pacific Region Citation Award, stating that the project, "...makes a bold — almost iconographic — statement in the landscape about renewable energy. It is a great demonstration piece and an impressive technical achievement. The architecture displays obvious concern for the environment and becomes a symbol — a teaching tool for sustainability."
What the Buzz Is All About
Designed as a thermal chimney, the Gateway is designed to capture heat by moving air through the building at a rate of 10 to 15 air changes per hour. The building's copper roof radiates heat from the sun into a ceiling plenum. As the hot air is exhausted, fresh outside air is pulled into the building from a vented under-floor plenum. Incoming air is drawn across cooling coils filled with 45°F seawater, maintaining temperatures between 72°F and 76°F without mechanical controls.
A drawing of a section through the Gateway Center shows how the building's thermal chimney cools the building by using natural convection to expel hot air. The diagram shows the coil under the floor of the building where cold seawater provides cooling. Fresh water that condenses on the cooling coils is captured and used.
Credit: NELHA
The building uses daylighting to negate the need for electric lighting during the day. The Gateway was also designed with an onsite, 20-kW photovoltaic array that provides all the energy needed on site. To conserve water, condensation is collected below the seawater cooling coils and used to flush toilets and irrigate deep-rooted landscaping.
Using Seawater for Air-Conditioning
One of the most innovative and effective uses of cold seawater used by NELHA and the Gateway buildings is cold deep seawater for natural cooling. The idea is to use the seawater for energy production, cooling, and commerce.
NELHA analysts have calculated that one of the most cost-effective uses for cold seawater is cooling a hotel, because the scale of cooling required matches closely the capacity of the cold-water pumps. The analysts calculate that in the warm climate at Kona, one hotel room requires one ton of air-conditioning load. This corresponds to 2.5 gallons per minute of cold seawater in cooling coils. Thus a 1,000-unit hotel requires 1,000 tons of air-conditioning that could be effectively served by a 2,500 GPM deep seawater cooling system.
Floating the Green Energy Zone
The warm-water intake at Keahole Point, Hawaii. Seawater pipes at NELHA are designed to have sufficient capacity to meet multiple potential uses, including electric power production, cooling for buildings, and seawater for additional commercial users.
Credit: NELHA
NELHA's plans involve creating a Green Energy Zone on the Island of Hawaii. Currently in the planning stages, this Green Energy Zone would increase tenant diversification at NELHA, create numerous high-tech jobs, and go from producing very little renewable energy to being energy self-sufficiency in a very short time.
Will Rolston, manager of the Hawaii Gateway Energy Center, is determined to see the Green Energy Zone happen. Governor Lingle is very committed to renewable energy as well, and Hawaii's administration is complementing NELHA's vision with its own by creating the Hawaii Clean Energy Initiative with DOE. "NELHA is doing an outstanding job in furthering our administration's efforts to foster the growth of renewable energy," Lingle said.
The Green Energy Zone would become the focal point for all of NELHA's renewable energy undertakings. A comingling of renewable energy, infrastructure, and economic development is already underway. The DOE National Renewable Energy Laboratory recognized this potential in 2004 and has provided funding to further advance distributed generation technologies.
With a plan in place to build roads connecting the Kona International Airport, adjacent highways, and NELHA, there is also a long-range vision to create an offshore OTEC. This new facility could produce 50-100 megawatts of electricity, millions of gallons of fresh water, and a sizeable amount of hydrogen for use in hybrid vehicles.
"NELHA is doing an outstanding job in furthering our administration's efforts to foster the growth of renewable energy."
— Hawaii Governor Linda Lingle.
Because three miles worth of pipes from the original OTEC infrastructure is already in place, NELHA's research tenants will be able to use it as a springboard for advances in renewable energy development. In fact, the 55-inch deep-seawater pipe was designed with future OTEC technology and experiments in mind.
The Green Energy Zone has also developed economic incentives for startups considering tenancy at NELHA, including fast-track permitting, tax incentives, and favorable lease arrangements. When one considers the economic benefits NELHA has to offer, it is easy to see why it is an exceptional research and commercialization facility for renewable energy.
About the Authors
Jennifer Josey, National Renewable Energy Laboratory
Jennifer Josey recently joined the National Renewable Energy Laboratory Program Support Office as a corporate communicator. Josey is a graduate from the University of Northern Colorado with Bachelor of Arts Degrees in English and communication; she is a writer and an editor.