High Voltage Partial Discharge (HVPD), SgurrControl, 2-B Energy, and Ocean Resource have received the funds, which will be specifically targeted at the design and installation of turbines.
Dutch turbine company 2-B Energy, which is developing a two-bladed turbine, has received £2.7 million. The first prototype will be installed in the Netherlands before testing at the Methil site, near Fife, Scotland.
The 2-B turbine has a 6MW capacity and a rotor diameter of 140-metres. It uses a lattice structure rather than a traditional tower.
Decc said it believes the turbine could reduce CoE by up to 35%, a reduction on the 45% figure claimed by Scottish Enterprise in 2012. Scottish Enterprise is also helping to fund the scheme.
The next highest award — £900,370 — will go to HVPD to develop monitoring technology to detect faults in HVDC cables.
SgurrControl's £667,000 is to help fund a control system to reduce stress on turbine blades, while Ocean Resource is developing an offshore turbine that is assembled onshore and towed to the site using tugs.