but some of the success has been due to oneoff factors such as the dash for gas reductions in nonc greenhouse gases in the s and the recent recession rather than explicit climatechange policies the pace of decarbonisation of the power sector has been slow and the spread of renewable energy technologies limited implicit carbon prices vary across sectors and should be harmonized to increase the cost efficiency of policy the unevenness partly reflects the way in which policies have proliferated and overlap and a simplified structure would be desirable