Business Green: Carbon credits will cost just $15 (£9.44) per ton during the first phase of the cap-and-trade scheme proposed as part of the Boxer-Kerry climate change bill that is currently working its way through Senate committees. That is the conclusion of a new model devised by industry analyst firm Point Carbon, which predicts that the average price for emission allowances under the scheme during the initial 2012 to 2019 period will not rise above the average price floor set by the …