Techdiplomacy

The relatively constant flow of ocean currents carries large amounts of energy that can be collected and used to generate electricity. Ocean waters move continuously. Ocean currents flow in complex patterns affected by the wind, water salinity and temperature, topography of the ocean floor, and the earth’s rotation. The ocean currents are driven by wind and solar heating of the waters near the equator, though some ocean currents result from density and salinity of water. These currents are relatively constant and flow in one direction, compared to the tidal currents closer to shore. Some examples of ocean currents are the Gulf Stream, Florida Straits Current, and California Current. While ocean currents move slowly, they carry a great deal of energy because of the density of water. Water is 800 times denser than air, so for the same surface area, water moving 12 miles per hour exerts about the same amount of force as a constant 110 mph wind. Ocean currents contain a substantial amount of energy. It has been estimated that taking just 1/1000th, of the available energy from the Gulf Stream would supply Florida with 35% of its electricity. The United States and other countries are researching ocean current energy, including Japan, China, and some European countries; however, marine current energy is at an early stage of development. There are no commercial grid-connected turbines currently operating; to date, only a small number of prototypes and demonstration units have been tested. Some of these technologies have been developed for use with tidal currents in near-shore environments; these near-shore tidal current energy technologies are not analyzed in the OCS Alternative Energy Programmatic EIS. The most likely scenario would be, energy would be extracted from ocean currents by using submerged water turbines similar to wind turbines. These turbines would have rotor blades, a generator for converting the rotational energy into electricity, and a means of transporting the electrical current for incorporation into the electrical grid. Also, there would need to be a way to keep the turbines stationary, such as concrete caissons, pile driven foundations, or cables anchored to the sea floor. Additional components might include concentrators (or shrouds) around the blades to increase the flow and power output from the turbine. In large open areas with fast currents, it would be possible to install water turbines in groups or clusters to make up a marine current “farm”, with a predicted density of up to 37 turbines per square kilometer. Space would be needed between the water turbines to eliminate wake-interaction effects and to allow access by maintenance crews and their vessels. Alternatives to water turbine designs have been proposed, including having a barge moored in the current stream with a large cable loop to which “parachutes” are fastened. The parachutes would be pushed by the current, then closed on their way back, forming a loop similar to a large horizontal water wheel. For ocean current energy to be utilized successfully at a commercial scale, a number of potential technical challenges need to be addressed, including: • avoidance of cavitations (bubble formation); • prevention of marine growth buildup; • reliability; and • corrosion resistance. Ocean current energy technology project planning will need to consider species protection (including fish and marine mammals) from injury from turning turbine blades. Consideration of shipping routes and present recreational uses, such as fishing and diving, will be required when considering where to locate the turbines. Other considerations include risks from slowing the current flow by extracting energy. Local effects, such as changes of estuary mixing resulting in temperature and salinity modifications, might affect species in estuaries.

This is not an overnight fix for our energy needs. However, in time, with more research, this could become a viable form of renewable energy. What do you think? Comment on this or any other post, you’ll start a lively conversation. See you around the galaxy…