Vattenfall, a Swedish energy company, has for years been doing preliminary work for what would be one of the world’s largest offshore wind complexes, in the North Sea off eastern England.Now, there are questions about whether this project will ever be built. Last month, Vattenfall said it would halt the first of three phases of the wind farm complex, the Norfolk Offshore Wind Zone, which is projected to provide power for about four million homes in Britain.Vattenfall blamed rapidly escalating costs for equipment and construction expenses, which they said had climbed as much as 40 percent over the past few quarters. The estimated price tag for the three phases has risen to 13 billion pounds, or about $16.6 billion, from £10 billio …
