Category Ocean Energy

Tidal Currents

Should tidal currents be discussed as part of tidal power or as a special type of marine current? The horizontal to and fro current due to the tidal phenomenon may be tapped in rivers as well as in estuaries or bays. It has thus seemed more logical to treat it separately here; tapping tidal current power has received recently more attention even if it has been a provider of mechanical energy in earlier times (tide mills).

Considering tidal currents, rather than tides themselves, poses new problems both from an environmental point of view and of that of power production. Considera­tions are in order because over the last two or three years there has developed (again) a real interest in tapping such currents for electricity production.

Robert Gordon University (UK) professors Bryden, Grinst...

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Marine Currents

There is no arguing that ocean currents represent an enormous energy potential. To harness it, there has been no shortage of proposals. Some projects envision tur­bines that are fixed on the seabottom, others would place them in the current itself, allowing several turbines to be attached at different depths to a single cable. As dis­tances to the consumer might be, in some instances, too great, industrial complexes were proposed in the middle of the ocean and the manufactured product would then be brought by ship to the continent.

A Canadian concern after testing six prototypes decided to construct a 2,200 MW ocean current energy conversion plant in the Philippines using a Davis Hydro Tur­bine...

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Marine Biomass Conversion

Little new has been reported in the area of marine biomass conversion even though the increase in algal biomass has caused serious concern to coastal regions, and in particular to resort towns. This is in opposition to the considerable progress made with biomass utilization for other purposes than electricity production.

Experts hold that the marine biomass conversion holds promise, has a future but predict that its development will be rather on a regional level, and on a modest scale.

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Ocean Thermal Energy Conversion

Sometimes referred to as thalassothermal energy [conversion], commonly desig­nated as OTEC. The OTEC uses the difference of temperature prevailing between different ocean waters layers to produce electrical power. Statisticians eager to im­press the amount of energy available stress that in the waters between the tropics the quantity of heat stored daily by the surface water layers in a square kilometer equals the burning of 2,700 barrels of oil.

The pilot projects of Arsene d’Arsonval and Georges Claude have been abun­dantly and repeatedly described; they date back to the first half of the last cen­tury.[50] Following the oil crisis of 1973, there was a new flurry of interest for OTEC and “Mini-OTEC” and “OTEC-1” were launched respectively in 1979 and 1980...

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Wave Power

The number of patents taken out on wave power activated machines is stunning, and they go back well over two hundred years. Probably the first to be taken out was by Girard, father and son in 1799 and proposed to take out mechanical energy using a raft. In the twentieth century buoys and lighthouses used wave-generated electricity. In the USA several attempts were made in California (San Francisco, Capitola, Pacifica). The power is provided by the onslaught of a breaking wave, which can be captured in a reservoir, accessible by way of a converging ramp, and connected with a return channel at the exit of a low pressure turbine. Power can also be generated by means of devices set directly in motion by the wave itself.[37]

Though diffuse, available power is impressive: there is more power rep...

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Marine Winds

Of all the ocean energies, marine winds have known the most important develop­ment during the last decades. They are a “renewable” which was easy to harness and which required only relatively modest capital investments. Sites are abundant, and a judicious choice permits to dampen the objections voiced because of the noise they cause. Marine wind “farms” have been implanted in numerous locations partic­ularly in Northern and Western Europe. However environmental-linked objections are being raised, spurring engineers to devise new approaches.

Most of the ocean energies require engineering developments to be harnessed and produce electricity, except the marine winds and the tides...

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Tidal Power

Anyone who has ever watched tides roll in on the coasts of Normandy or Brittany, on the estuary of the Severn River or in the Bay of Fundy, cannot help but be awed by the force that is unleashed. The phenomenon had, of course, already been observed in Classical Times and this power was put to work on rivers such as the Tiber River in Rome, the joint estuary of the Tigris and Euphrates rivers even much earlier. Tide mills on the Danube may date from later periods. Mechanical power was sought to grind grain, to power sawmills, to lift heavy loads.[3] [4] [5]

These tide mills are of course not different from run-of-the-river mills, except that they include an impounding basin where the water brought in by the incom­ing (flood) tide is stored: At ebb tide the water is released but has to pass ...

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Poseidon to the Rescue: Mining the Sea for Energy—A Sustainable Extraction

1.1 Energy From The Ocean

The first sources of ocean energy that come to mind are the hydrocarbons. From timid extraction operations hugging the coastline and shallow depth wells, not too difficult to cap, giant steps have been made, to the point that platforms have been erected, far out at sea, and oil is obtained from ever-greater depths. The value of methane has become more apparent during the last half-century and gaso-ducts—gas-pipelines—cross ever longer water and land expanses, just as oleo – ducts, the oil carrying pipelines, do. However, with the urgent need to reduce green­house gas emissions, the love affair with gas and oil has considerably tapered down.

The ocean bottom has also yielded coal from mines accessible from land or at sea: Scotland, Taiwan and Japan, for instan...

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