Overlooked Oceanic Sci-fi Technologies

It's been said that we know more about outer space than the oceans. Although it's impossible to compare our expertise in two environments that are so vastly different, it's certainly true that outer space has captivated the imagination far more than the ocean. Space may be our "final frontier," but there are still many emerging ocean technologies left to explore. For that reason, I'd like to highlight some developing oceanic technologies which are at least as important as the highly publicized recent progress in space exploration.

Ocean Thermal Energy Conversion

It may seem complicated at first glance, but ocean thermal energy conversion (OTEC) is simply the way of using the difference in temperature between superficial and deep water in the ocean to create electricity [1]. The two main types of OTEC systems are open and closed. A closed system uses the warm surface water to boil a gas with a relatively low boiling point, like ammonia, which then spins a turbine to generate electricity. The cold water is used to cool down the hot gas so that it can be used again. An open system takes the warm water into a container with low enough pressure that the water evaporates, which causes turbines to spin and electricity to be produced. The advantage of this system is that the steam is extremely pure water, and it can be cooled by the deep, cold water to produce drinking water as a byproduct, which has numerous applications to humans and the environment as a whole, as illustrated below.

Lumos3 via Wikipedia

Analyzing OTEC's efficiency with thermodynamics and Carnot's theorem leads to two conclusions. First, places with greater temperature differences (as shown in the map below) are better potential places for OTEC plants. Second, OTEC is quite inefficient, with more than 90% of energy wasted [2]. Unfortunately, that inefficiency, coupled with high startup costs, has been a huge obstacle to widespread implementation. In the future, we hope to see this emerge as a viable alternative energy source. Japan recently constructed the first OTEC plant at Kume Island, and the Japanese marketing group Fuji Keizai predicts a substantial growth for the technology in the coming years [3].

Obersachse via Wikipedia

Iron Fertilization

Iron fertilization (or iron seeding) is the process of inserting quantities of iron into the ocean to induce a plankton boom. The plankton boom absorbs large quantities of carbon dioxide for photosynthesis, combating climate change. Early experiments and analyses of past iron fertilization were extremely promising; however, more recent research has raised concerns about the potentially negative long term impact of iron seeding [4]. Additionally, many subsequent experiments have had underwhelming results, with some having had no results at all [5]. In fact, a recent report shows that too much iron can cause diatoms (a kind of plankton) to intake so much iron that they sink to the ocean floor, preventing the iron from being used by other species [6]. Although iron fertilization is the most controversial of the technologies on this list, it shows some promise, and if it can be shown to work on large scales, it could become a powerful weapon against climate change. The largest test of iron seeding was conducted by Russ George, who put one hundred tons of iron sulfate into the waters off the coast of Canada in late 2012 [7]. His independent action was controversial, to say the least. A substantial bloom did form, but the long term effects are not yet clear, especially because of the haphazard nature of the fertilization. Perhaps more controlled research will help determine the merits of iron fertilization for the future.

Wave Power

Wave power describes attempts to use the motion of the ocean's waves to generate electricity. Some advantages of this intuitive sounding technology are the high and untapped potential energy from waves, the consistency of power generation from waves as compared to solar and wind (90% vs 30%), and easy placement of wave power plants, as high energy waves occur across the world [8]. However, some challenges include the potential negative impact on the environment, competition with fisherman and offshore wind turbines for space, and connection to the power grid. In spite of these challenges, efforts to harness wave power are underway and we could see wave power come to fruition as a viable, clean form of alternative energy.

It's too early to tell whether or not any of these technologies will become a major part of our future in terms of combatting climate change or as an alternative energy form. They all have their own risks and promises, and only time will tell if they are successful. Although we all like to turn to the stars for answers, perhaps we should look to the sea instead.

[1] Vegas, L. A. "Ocean Thermal Energy Conversion Prime." Marine Technology Society Journal 6.4 (2002/2003): 25-35.

[2] Masutani, S. M., and P. K. Takahashi. "Ocean Thermal Energy Conversion." Marine Policy & Economics: A Derivative of the Encyclopedia of Ocean Sciences. London: Elsevier, 2010. 291-97.

[3] "Japanese Market Research Firm Forecasts Growth of Offshore Wind and Ocean Thermal Energy Conversion Power Generation." Japanfs.org. Japan for Sustainibility, 26 Sept. 2013. Web. 23 Feb. 2014.

[4] Powell, Hugh. "Fertilizing the Ocean with Iron."Oceanus Magazine. Woods Hole Oceanographic Institute, 13 Nov. 2007. Web. 20 Feb. 2014.

[5] Waller, Rhian. "Iron Fertilization: Savior to Climate Change or Ocean Dumping?" National Geographic. National Geographic, 18 Oct. 2012. Web. 20 Feb. 2014.

[6] DOE/Argonne National Laboratory. "Iron fertilization, process of putting iron into ocean to help capture carbon, could backfire." ScienceDaily. ScienceDaily, 12 June 2013.

[7] Vaidyanathan, Gayathri. "Iron Fertilization Develops a New Wrinkle." Discovery News, 17 July 2013. Web. 23 Feb. 2014.

[8] Drew, B., A. R. Plummer, and M. N. Sahinkaya. "A Review of Wave Energy Converter Technology." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 223.8 (2009): 887-902.