Tidal power / Energia mareomotriz

Uma turbina submersa que gera energia elétrica das correntes de marés entrou em funcionamento na Grã Bretanha.

Estimativas dizem que há cerca de 15 Gigawatts de energia potencial mareomotriz no Reino Unido.

A turbina SeaGen foi projetada e fabricada pela empresa de Bristol (Inglaterra) Marine Current Turbines (MCT).

"A melhor maneira de ter uma idéia a respeito é imaginar um moinho de vento submarino", diz a empresa. Há grandes massas de água se movendo pela Terra pela ação gravitacional exercida pela Lua. A vantagem da energia das marés é que elas são previsíveis, constantes, ao contrário dos ventos.

O custo de instalação destas turbinas é de US$ 6 milhões por megawatt de capacidade geradora, em comparação com US$ 4,6 milhões das eólicas offshore. O custo deverá cair à medida que a produção aumentar.

An underwater turbine that generates electricity from tidal streams was plugged into the UK's national grid today.

Tidal streams are seen by many as a plentiful and predictable supply of clean energy. The most conservative estimates suggest there is at least five gigawatts of power in tidal flows around the country, but there could be as much as 15GW.

SeaGen was designed and built by the Bristol-based tidal energy company Marine Current Turbines (MCT).

"The best way to think of it is an underwater windmill," said Martin Wright, managing director of MCT. "There are big masses of water moving on the Earth's surface as a result of the gravitational attraction of the moon.

Tidal generators harvest the energy of these moving streams with the added advantage that the resource is, unlike wind, predictable.

"The cost of installing the marine turbines is £3m for every megawatt they eventually generate, which compares to £2.3m per megawatt for offshore wind. The costs will drop if the technology is more widely adopted.