Ministers extended the limit before the deadline of November 27th, which is the date on which the Energy Bill is sent to receive Royal Assent.
It is hoped the feed-in tariffs, in which householders or groups who generate their own energy would be paid by big energy suppliers, will be in place within 16 months.
Mr O'Brien said: "Our ideal target is for the scheme to go live in April 2010, so that it can be aligned with the financial year of the renewables obligation."
Energy Secretary Ed Miliband met representatives from the large energy providers earlier this week, ahead of the December 1st deadline when the firms must prove to Ofgem they are not over-charging pre-payment meter customers.
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