Chris Huhne, British secretary of state for energy and climate change, said London was focused on the "easy wins" like better insulation, improving fuel efficiency of new cars and building more gas- and renewable-fired energy technology.
Making the British economy green in the short term, he said, is progressing. Long-term costs, however, could range from a $1.5 billion benefit to a $31.4 billion benefit.
"Every bit of progress we make is one more step away from import dependency, away from price volatility and from the emissions that threaten our way of life," he said in a statement. "Our national economic interest is to be found in a cost-effective transition to low carbon, to an economy that is more resilient, innovative and efficient."
He said the British economy cut emissions by 25 percent of 1990 levels but more work is needed.
If there are no transformations in the British economy, he said, fossil imports will increase from 2007 of 23 percent of the overall energy mix to 88 percent by 2050. Without a move away from fossil fuels, British consumers can expect to pay $7,355 per year on energy costs by 2050.