The energy regulator has announced there will be a grace period to begin claiming the subsidy after the 31 March 2017 deadline.
After that date, large-scale projects will only be able to apply for the government's new contracts for difference programme.
Ofgem said the grace periods should stop there being an "investment hiatus" during the transition period between the two schemes.
Offshore developers wishing to apply for the RO scheme up to 12 months after the closing date must supply Ofgem with a notice of intent by 9 November 2014. They must also provide evidence that the project can go ahead.Developers will need to have planning permission and a grid connection offer from a network operator to qualify. They must also prove they have enough resources to commission the project.
Eligibility is restricted to renewable projects expected to enter commissioning on or before the end of March 2017.
Ofgem has also allowed Scottish offshore wind demonstration projects to apply for an 18-month grace period.