According to figures from greenfield investment monitor fDi Intelligence, the sector has seen a 336% jump in the first four months of 2009 compared with the same period in 2008.

Investors may have been encouraged by new regulation in the sector brought in by the new administration, which guarantees federal-level tax credits for renewable energy investors until 2013. Recent investments include German energy giant E.ON’s 109-­turbine wind farm in Corpus Christi, Texas, to be completed by the end of 2009.