Intermittent Renewable Energy? Not for Ocean Thermal Energy Conversion (OTEC)

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Written By: Emma Websdale

Recognized as one of the greatest threats to human and wildlife security, climate change is having profound impacts on our weather systems, habitats, agricultural production, and even our behavior. Fortunately, one of the most significant contributors to climate change, our dependency on fossil fuels, is something that we can change.

Renewable energy options pave the way to a future in which carbon emissions, released during the burning of fossil fuels, can be reduced dramatically, helping us live sustainable and healthier lives.

Some renewable energy technologies run intermittently. Others generate surplus energy that goes to waste because it cannot be stored. Because of these issues, not everyone has confidence in the dependability of renewable energy to meet our future needs. Luckily, a renewable energy technology that produces constant clean energy and comes with no energy-storage issues already exists—Ocean Thermal Energy Conversion (OTEC).

4242895085With the ocean covering more than 70% of the Earth’s surface, its energy storage potential is enormous. Over the course of 24 hours, tropical ocean waters absorb solar radiation equivalent to the amount of energy that can be produced by 250 billion barrels of oil.

OTEC is a renewable technology that taps into this enormous energy store by utilizing the temperature difference between cold deep waters and warm surface waters to produce clean energy. Because the thermal resources of the ocean are available day and night, with only relatively small variations from summer to winter, OTEC can produce clean energy 24 hours a day, seven days a week, giving it a great advantage over other important, yet intermittent, renewable energy sources.

Another major, competitive benefit of OTEC is its range of secondary services, most notably the production of fresh drinking water. By warming and desalinating (removing salt and other minerals) seawater, OTEC renders it suitable for drinking. This fresh water can also be used to support agriculture and aquaculture industries, reducing demand on local water supplies. When energy generated by an OTEC plant is not used to provide electricity for domestic purposes, it can be used to power desalination plants, ensuring that OTEC-produced energy is never wasted.

One 10-megawatt (MW) OTEC plant can provide reliable, clean energy for approximately 10,000 people, replacing the burning of 50,000 barrels of oil and preventing the release of 80,000 tons of carbon dioxide (CO2) per year into the atmosphere. When the plant’s energy is not in demand, that same 10-MW plant can produce as much as 75 million liters of fresh drinking water on a daily basis.

Onshore OTEC Plant

OTEC’s global importance is reflected in data from the National Renewable Energy Laboratory (NREL) of the United States Department of Energy (DOE), which lists 68 countries and 29 territories as good candidates for OTEC plants. Furthermore, a study performed by Dunbar identified 98 territories with access to the OTEC thermal resource (an ocean temperature differential between warm surface water and deep cold water of at least 20°C), making both floating and land-based plants appropriate to vast areas.

By converting our ocean’s abundant temperature differences into clean energy, and by helping to reduce CO2 emissions, OTEC’s 24/7 reliability is ensuring the technology’s position in the renewable-energy market.

For more information on how you can support OTE’s mission, please click here.