 GREEN energy firms ready to start work on schemes supported by a new UK Government incentive have been hit by a last-minute delay to its launch.  Suppliers and installers of renewable energy systems were infuriated by news that the Renewable Heat Incentive (RHI) was to be postponed.  Industry figures say projects which would have helped achieve dramatic cuts in Scotland s carbon emissions are being threatened by political dithering   and claim some firms may even go out of business.  The incentive had been due to come on stream when a last-minute announcement from the Department of Energy &amp; Climate Change (DECC) threw plans into turmoil.  We were dismayed and insulted by the email we received,  said Richard de Silva, director of Greenflame Technology in Kincraig.  They talk of understanding our frustration but it s people s livelihoods that are at stake here.  He said the uncertainty was creating mistrust among customers considering installing renewables like woodfuel boilers, solar thermal systems and heat pumps. The RHI for both domestic and commercial systems was originally due to be launched in april. a review saw the launch dates split, with incentives for commercial schemes to be introduced on October 1, and domestic in autumn 2012.  a DECC spokesperson said:  The European Commission state aid approval for the RHI will be subject to a reduction in the large biomass tariff. This means we now need to change the regulations   we hope to open the scheme before the end of November.