The supplier obligation (now termed the Carbon Emissions Reduction Target) has been set over three year cycles precisely to allow the Government to reflect on its successes and to evolve the scheme so that it only pulls through the most energy efficient products with the most potential to provide for household sector carbon emissions reductions. The measures eligible for each phase are subject to full public consultation. The consultation on the April 2011 to December 2012 extension of the Carbon Emissions Reduction Target, concluding on 14 March 2010, does though specifically ask whether the Government should introduce up front sunset clauses for products when they reach a certain level of market penetration.
An independent assessment is commissioned at the end of each three year phase of the Supplier Obligation (now termed the Carbon Emissions Reduction Target), building on the cost-benefit assessment undertaken and published at the launch of each scheme. Independent analysis of the three year supplier obligation scheme ending March 2008 showed it to have been extremely cost effective in delivery—that for every £1 added on to GB household bills to pay for the obligation, benefits equate to an average saving of £9 per household bill over the lifetime of the measures. Equally, the present supplier obligation, the Carbon Emissions Reduction Target, is believed to be highly cost-effective, with expected annual benefits (net of costs) of around £649 million for the lifetime of the measures, with around £228 benefits per tonne of carbon dioxide saved in the traded sector and £153 benefits per tonne of CO2 saved in the non-traded sector.