Abbott is on about "direct action" still isn't he? Thats not an ETS unless hes changed it a LOT. The Carbon tax was always a carbon price moving to a market based mechanism, in which polluters pay for the CO2 they emit. Thats not the way Direct Action works.
Direct Action gives $$$ to those who reduce (or at least don't increase) their CO2 output. Last I heard it was unlikely those increasing their output would be penalised. This is all tax dollars being directly given to industry, in a one way flow of money.
Under direct action, it would be utterly pointless to pay subsidies. All you would be doing is giving people money then taxing it back out of them to pay for the scheme.
Under the Carbon Tax / ETS, polluters pay extra tax to the govt, and some of that is returned to the taxpayer via the subsidies.