 Duke Energy Corp. confirms that the four partners in the Constitution Pipeline have agreed to abandon the 124-mile project designed to carry natural gas from shale fields in Pennsylvania to New York and New England. Although Constitution did receive positive outcomes in recent court proceedings and permit applications, the economics associated with this greenfield project have since changed in such a way that they no longer justify investment, says Duke spokeswoman Tammie McGee. The delays and legal challenges have since driven up the costs by close to 40. 