An
offshore example
The kind of installation that can fit the
requirements of being capable of placing its output into the national grid and being
economically viable in other respects is indeed a large animal. A typical example is an
offshore wind farm currently being proposed for a location in the Irish Sea, some 22km
south-east of Dundalk on the east coast of Ireland by a company called Oriel Windfarm
Limited.
The
proposal is that this project will comprise of 55 turbines built on the seabed in 30m of
water. Each tower will extend 160m from the mean sea level to the tip of the uppermost
turbine blade. This makes the total height of each wind turbine equal to around half that
of the Eiffel Tower in Paris, or a full 80m higher than the top of the cross on the dome
of St. Paul’s Cathedral in London. The foundations alone, which will comprise, for
each tower, of a massive concrete structure resting on the seabed, are a major feat of
engineering in themselves. The full wind farm will cover an area of 28 square km., or the
equivalent of no less than 5,900 soccer pitches. One reason for all this space is the
requirement that each turbine is not affected by any of its neighbours. The laws governing
the conservation of energy are as applicable here as anywhere else. When wind energy is
trapped by a turbine it loses a lot of its potential to be useful for another tower
immediately downwind of the first one. For this reason the layout of a wind farm is of
some importance to its overall effectiveness.
When
complete the wind farm described here will generate power of between 250 and 330 mW
(megawatts) or enough to cater for the electricity requirements of approximately 250,000
average Irish households. It will cost around €500 million.
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