The ETI plans to design, construct and install the pilot at a relatively near-shore site with wind speeds of up to 10m/s at 60- to 100-metre water depth.
The floating demonstrator will operate for at least two years to show it can generate high levels of electricity and be maintained without using specially designed vessels.
The ETI will commission a test site and ask project participants early next year to provide a 5-7MW offshore wind turbine that can be installed on the floating platform.
David Clarke, ETI CEO, said: "We expect there is likely to be a considerable global market for floating wind turbines which can be developed in the UK."
The ETI is a public-private partnership between six global industrial companies and the UK government. It has announced investments of £43 million in offshore wind.