I think it is a slow down rather than a cancellation scenario. But jobs will be lost in the insulation industry I would imagine.
Oh goodness - Green Deal - a property owner takes out a loan to improve the energy efficiency of the property. The measures have to be assessed as effective (approved software is used by a licenced person - a Green Deal Assessor). The cost of the loan is paid back by the electricity company deducting a small amount from the bills over 20 (I think) years and passing it on to the body that made the original loan. There is a "golden rule" that your energy bills (gas plus electric) will be no higher than they were before.
However the bills may not be any lower in the short term. But if energy prices rise, the savings will become significant.
If you sell the house the green deal charge passes to the new owner.
The problem is that (without me being super tedious listing all the ins and outs, which are considerable) the cost of managing all this, and hence the cost of the loans, is going to be about 7% pa.
So many householders would be better off, if they need a new boiler for instance, in adding the cost of this to their mortgage.
That is as simple as I can make it.
If anyone needs insulation or a new boiler the best thing is to first check out with their energy company (and other energy companies) whether they are entitled to anything free, or subsidised, under the many current ECO schemes. (see the links on the energy saving tips thread)