Developing OTEC Pilot Schemes
Companies such as Lockheed Martin are working with Makai Ocean Engineering and leading the way in designing and operating pilot schemes such as these, which are demonstrating ever greater commercial and technological feasibility. The principles behind Hawaii Design Test Facility are all about making the forward steps to achieve the world’s first commercially viable 100MW OTEC power plant.
OTEC Test Facility Hawaii
In 2011, Makai Ocean Engineering completed tests of the first OTEC testing facility on the island of Hawaii, USA. The testing facility consisted of designing and building a heat exchanger which is one of the key components in OTEC technology. This is where warmer and colder water are allowed to flow in and out to warm-up and cool the low temperature liquid required in the process. Makai Ocean Engineering was perfectly placed to build this facility, leveraging from Natural Energy Laboratory of Hawaii’s (NELHA’s) existing deep seawater piping infrastructure, which is absolutely essential for this technology to work effectively.
At the NELHA, a 40ft tall tower was built, including the heat exchanger, which is the single most expensive component in this technology (small efficiency gains in the heat exchanger technology can make great leaps in lowering the cost). The tower facility supports evaporators, condensers, sea water piping and accurately allowing the ammonium fluid to flow through the system.
The funding pot unlike those that have been demonstrated in other case studies is coming from public or research bodies due to a lack of fully commercially available projects. In this case the funding has been provided by the Naval Facilities Engineering Command and the Office of Naval Research.
OTEC technology has been proven to have a minimal impact on the environment. In this case of heat exchangers, there is zero impact on the environment (the testing of the heat exchangers, involving NELHA’s state of the art deep seawater infrastructure, has been proven to have no impact on the local marine ecosystem around it).
OTE Corporation Bahamas OTEC Power Plant
To be effective, companies such as OTE Corporation are bringing together both Ocean Thermal Energy Conversion (OTEC) and Seawater District Cooling (SDC) solutions, to leverage the benefits of the infrastructure that is put in place. OTE Corporation’s current plan is to construct the world’s first two commercially viable OTEC plants in the Bahamas which would be able to generate between 5-10MWs of electricity, 24/7. OTE Corporations unique capabilities in deepwater piping means that these types of facilities will be able to support energy generation of this size and also be both technologically and commercially viable. A Memorandum of Understanding (MoU) has been signed with the Bahamas Electricity Corporation (BEC) and a preliminary Power Purchasing Agreement (PPA) with a major Pacific utility company, which means this project is a few steps closer to getting the green light.
OTE Corporation Seawater District Cooling Solution
In parallel, OTE Corporation has been selected to construct the world’s largest deep ocean Seawater District Cooling (SDC) facility, which would bring about 80-90% saving in electricity usage for air-conditioning in this world famous luxury resort. The Energy Services Agreement is in place and once again the project is closer now to getting the green light to proceed.
OTEC Economic Feasibility
From a technological perspective, the more the component parts are improved means that from a economic perspective costs are able to be reduced. This then goes a long way to make OTEC solutions more economically feasible. For example, making sure that the heat exchanger has low corrosion levels means that repair and servicing costs fall and overall profitability levels of a plant will increase.
OTEC Environmental Impact
From an environmental perspective the build process will hinge on the piping infrastructure being put in place without interrupting local marine ecosystems. The piping system is buried deep in the ocean, which means it takes water that contains high nitrate concentrations, otherwise useful to support marine life. Also a 10m diameter pipe is needed to pump enough water to support a 100MW plant. This is why the infrastructure has to be created so it doesn’t have a detrimental effect on the environment around it, which would be counterintuitive to the principles behind OTEC and also defeat the purpose of this technology. Studies are taking place to look at the impact a plant would have on the marine life around it. 3D modelling for example has been able to project the area that will be affected by an OTEC power plant and nutrient extraction levels. These studies help companies like OTE Corporation work through improving the technological solutions to mitigate these impacts.