To be eligible for the contract, wind farms can only use floating turbines. These must be at least ten miles from the mainland and inhabited islands, in water at least 300 feet deep.
Developers must also demonstrate the capacity to later develop an offshore project of 100MW or greater.
Proposals for the initial 30MW must be submitted to the commission by May 1, 2011.
State legislation passed last April required the PUC to issue the offshore RFP.
The commission may authorise one or more power purchase agreements (PPAs) for the 30MW.
Its selected developer will enter into a PPA of up to 20 years with one of two utilities, Central Maine Power or Bangor Hydro.
There are currently no utility-scale floating wind farms, although a number of concepts are in development.
Norwegian energy company Statoil recently announced it is considering Maine, alongside Norway and Scotland, as a test site for the commercial potential of floating wind turbines.
Statoil has said it will choose one of the three locations by 2011, according to Bloomberg.
The company is already testing a floating 2.3MW Siemens turbine off the coast of Norway, at a depth of 220 metres.