Ewing said it was right the Conservative majority government should implement its election manifesto, but pointed out the Conservative's pledge was to "end any new public subsidy" for onshore wind, not cut existing ones.
The Renewables Obligation has been in place since 2002 and was originally planned to be phased out in 2017, to be replaced by the Contracts for Difference. Rudd announced last week the subsidy would be closed a year earlier, in 2016.
Ewing said: "When a government sets a consistent policy, the government must be consistent."
There "needs to be clarity" beyond 2020, the Scottish minister said, echoing what was said in the opening session of the day.
Ewing announced that the Scottish Parliament will take over responsibility from the UK Crown Estate of the waters around Scotland, and added that the "complex" marine consenting processs would be simplified.
He encouraged the deployment of floating offshore wind, arguing it makes sense to develop the technology for the deeper waters around Scotland.