OTEC & Climate Change
Earths Oceans
The ocean comprises 70% of the Earth’s surface. Climate change is causing an increase in the temperature of the ocean’s currents, which are also experiencing a modification of their lanes of travel. As arctic ice melts, the volume of water impacts on ocean levels, threatening seaside cities. And, as the ocean warms, oxygen levels are decreasing in key areas, methane levels are rising in sub-arctic regions, and sea life is being threatened in dramatic fashion.
Along comes a technology that impacts on and is impacted by ocean water temperatures – OTEC – and inevitable questions arise. How will OTEC be impacted by climate change, and more importantly, how will the climate be impacted by OTEC.
Ironically, it is the former question and not the latter that has scientists excited.
OTEC involves piping nutrient-rich cold water from the deep levels of the tropical ocean, exchanging it for warm surface water. Concern is being raised about the potential for this nutrient-rich water to infiltrate the surface shorelines, causing algae blooms that starve the ocean wildlife of oxygen, and creating dead zones. However, the algae and plankton blooms pull CO2 from the air, providing oxygen to the atmosphere.
If OTEC can cause ocean algae blooms, then it can also be used to develop aquaculture and mariculture.
This problem & benefit balance appears to be miniscule in comparison to the potential benefit of OTEC development. In terms of energy potential, ocean thermal energy’s big selling point is that it is always “on,” and its always available, unlike solar that requires sunlight and wind that requires, of course, wind. And the ocean is a vast storage battery of energy, while solar and wind’s big drawback is the inability to “save up” energy.
The primary attraction to those seeking ways to mitigate the damage of ocean warming on our climate, and vice versa, is the impact of the exchange of hot and cold water on ocean thermal balance. Currently (no pun intended), the ocean is a vast circulation system, with warm water from the tropics flowing northward, where, as it cools, it falls. Drawing its way back to the tropics, where it is heated by the sun and diluted by salt-free rains. Here, it begins its journey to the arctic regions again. The process, known as thermohaline circulation, is considered to be at risk of shutting down as a consequence of global warming.
But OTEC rides to the rescue. By drawing up the cold water near the equator, and cooling the surface water, the flow of too-warm water to the arctic regions is slowed, and, as a result, the impact of cooler water on arctic ice melt and methane gas release from the permafrost below the seas inhibits the negative impacts currently experienced by out-of-balance currents.
It may be a first: drawing on the world’s energy stores actually will have a positive impact on the environment, and may be the white knight of climate change mitigation.
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