ON THE MARCH

摘要

It looks like Guy Maunsell's abandoned and rusting defence towers, which have benignly broken the flat line of the horizon line off the north Kent coast since 1942, might have some competition on their hands. This month, 12 miles off the Kent and Essex coasts in the Outer Thames Estuary, the foundations will start to be sunk for the £3bn London Array offshore wind farm. Covering an area of 100km2, the 175 turbines — each weighing 1,400 tonnes and rising a total of 175m above sea level to the tip of its three 60m radius rotor blades — will make their presence felt where sea meets sky. With first energisation and power output set for November 2011, each turbine will have a yearly offset of 2,ooot of carbon and have a generative capacity of 3.6MW, meaning that by the time the second phase of the London Array goes online in the last quarter of 2012, its total generative capacity will exceed 1GW - enough to meet the electricity needs of 750,000 homes and displacing 1.9m tonnes of carbon dioxide each year.