I don't see how this strategy, welcome though it is in principle (the green taxes should certainly be levied through general taxation), is going to counter Labour's plans for a price freeze in conjunction with a major review of the whole business.
The whole energy pricing thing is bizarre. I've never really understood how it can be in the interests of energy companies to promote "green energy" or energy conservation. They want to sell power, and it's bad news for them if people are using less. The free insulation thing is simply part of a business plan to have private customers using less of their power so that higher-rate business customers can use more.