The Estate, which owns most of the seabed off Britain's shores, regularly leases out its land to wind farm projects but has never invested in the turbines.
With a capacity of 7.5 megawatts, the Crown has gone for the biggest yet.
"This is not something we've ever done before and I think it will raise quite a few eyebrows," Ben Barton, the company's offshore manager for wind farms said.
Speaking at an energy conference in Aberdeen, Barton said the Crown Estate had decided to make the investment to help overcome turbine supply difficulties, which he said were a key constraint to the construction of off-shore wind farms.
The turbine will be built by the London-listed wind turbine maker Clipper Windpower and will be fully operational by 2010, Barton said, with all the power generated to be sold to the national grid.
The Crown Estate is looking at areas in north-east England as a possible site for the project, he said.
The company also said it was seeking initial expressions of interest from firms wishing to be considered for developing 100 MW or more capacity in Scottish waters.