Ocean Turbines

Covering more than 70% of the Earth’s surface, the ocean is the world’s largest untapped, renewable energy resource. It produces both mechanical energy from its tides and waves and thermal energy from the sun’s heat. As new technologies are developed, ocean resources will be able to meet many of the world’s energy needs. Experts estimate that 0.2% of the ocean’s untapped energy could power the entire world. The value proposition for ocean power is twofold. First, ocean power technologies have been practiced for hundreds of years. They are based on well-understood principles derived from hydrodynamic physics and mechanical and electrical engineering. As such, the capital and energy cost paths for ocean power technologies are relatively predictable. Second, ocean energy is an abundant, predictable and renewable resource. Tides and marine currents are 832 times denser than the air flowing over wind turbines and are predictable up to the minute at least 100 years in advance. Ocean energies are guaranteed to deliver high output indefinitely. Of all the renewable energy technologies, tidal power is the most predictable, reliable and dispatchable (the ability of a given power source to increase and/or decrease output quickly on demand). Twice a day, the gravitational pull of the moon causes water to flow in from the ocean on strong flood tides and flow out again on equally powerful ebb tides. Tides occur reliably, independent of weather and climate change and they follow predictable lunar orbits known many years in advance. There are two ways of creating tidal power: tidal dams and ocean currents. Dams are based on using an “at a bay” or estuary with a large tidal range. Power is generated primarily at ebb tides as the barrage creates a significant head of water, much like a hydroelectric dam. Tidal turbines take advantage of fast-flowing ocean currents to create energy. The most prolific tidal turbines are horizontal axis turbines that in many ways are analogous to wind turbines. The main difference is size. Tidal turbines generating 1 MW of power can be up to one-third the size of a wind turbine with a similar generating capacity. Waves caused by wind blowing over the surface of the ocean carry tremendous energy. The total power of waves breaking around the world’s coastlines is estimated at 2-3 million megawatts. Ocean wave energy is captured directly from surface waves or from pressure fluctuations below the surface. The prevailing technology is point absorbers, which resemble offshore buoys that measure environmental data except they are larger. Their popularity is due to their ability to absorb energy from oncoming waves in all directions. Wave action could power as much as 10 percent of the world’s electrical demand someday. Ocean thermal energy is created when the sun’s heat warms the surface water, while the deep ocean water remains cold. In tropical regions, the surface water can be more than 40 degrees warmer than the deep water. Ocean Thermal Energy Conversion (OTEC) is a method for generating electricity by taking advantage of this vast temperature difference. There are three types of electricity conversion systems:closed-cycle, open-cycle, and hybrid. Closed-cycle systems use the ocean’s warm surface water to vaporize a working fluid, which has a low-boiling point, such as ammonia. The vapor expands and turns a turbine. The turbine then activates a generator to produce electricity. Open-cycle systems actually boil the seawater by operating at low pressures. This produces steam that passes through a turbine/generator. Hybrid systems combine both closed-cycle and open-cycle systems. OTEC has been used successfully in Hawaii since 1974. ((18 OCT 2010))




Sea God







Give this job to the people who build ocean oil rigs. And let’s see some results.

If they can put a man on the moon, they can build an ocean turbine. So let’s not hear any excuses.




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