Suzlon Wind Energy Corporation, the US-based subsidiary of Suzlon Energy, has extended its contract with PPM Energy of Portland, Oregon, US to add 300 MW of wind turbine capacity.According to a release issued by Suzlon to the BSE today, the original agreement was for delivery of 300 MW turbine capacity in 2008 and 100 MW of capacity in 2009, but now has been extended to include an additional 300 MW in 2009 for a total of 700 MW over two years.Following the additional requirement, the order has now become one of the largest single contracts in the history of Suzlon and the US wind energy industry, the release added.