German engineering giant Siemens said Thursday it has won a 1.5-billion-euro ($2.0-billion) contract to supply wind turbines to a huge offshore wind park being built off the Dutch coast. Siemens said in a statement it will deliver 150 wind turbines with a capacity of four megawatt for a wind power plant located in the North Sea, 85 kilometres (53 miles) above the coast of Groningen. With an installed capacity of 600 megawatt in total, the "Gemini" wind park will yield 2.6 terawatt hours (TWh) of electricity per year and supply clean energy for one and a half million people after being fully commissioned. "For Siemens this is the first order for an offshore wind power plant in Dutch waters," the German company said in a statement. And the 15-year service and maintenance agreement for the Gemini project "is the largest service order ever for Siemens Energy Service," the statement said.