Dynamic tidal power

Dynamic tidal power or DTP is an untried but promising technology for tidal power generation. It would involve creating a long dam-like structure perpendicular to the coast, with the option for a coast-parallel barrier at the far end, forming a large 'T' shape. This long T-dam would interfere with coast-parallel tidal wave hydrodynamics, creating water level differences on opposite sides of the barrier which drive a series of bi-directional turbines installed in the dam. Oscillating tidal waves which run along the coasts of continental shelves, containing powerful hydraulic currents, are common in e.g. China, Korea, and the UK.

The concept was invented and patented in 1997 by Dutch coastal engineers Kees Hulsbergen and Rob Steijn.

A short video explaining the concept was completed in October 2013 and made available in English on YouTube and in Chinese on Youku.

A DTP dam is a long barrier of 30 km or more which is built perpendicular to the coast, running straight out into the sea, without enclosing an area. Along many coasts of the world, the main tidal movement runs parallel to the coastline: the entire mass of the ocean water accelerates in one direction, and later in the day back the other way. A DTP dam is long enough to exert an influence on the horizontal tidal movement, which generates a water level differential (head) over both sides of the dam. The head can be converted into power, using a long series of conventional low-head turbines installed in the dam.

Estimates of the maximum head difference that can be obtained from a variety of dam configurations are based on numerical and analytical models. Field information from measured water level differences across natural barriers confirms the creation of significant head. The (maximum) head difference is more than what would be expected in stationary flow situations (such as rivers). The maximum head difference reaches values up to a few m, which can be attributed to the non-permanent character of the tidal flow (acceleration).

It is estimated that some of the largest dams could accommodate over 15 GW (15000 MW) of installed capacity. A DTP dam with 8 GW installed capacity and a capacity factor of about 30%, could generate about 21 TWh annually. To put this number in perspective, an average European person consumes about 6800 kWh per year, so one DTP dam could supply energy for about 3 million Europeans.

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Wikipedia